Effect of twinning and sex on carcass weight and composition in lambs - McCoard SA; Koolaard J; Charteris A; Luo D (Proceedings of the New Zealand Society of Animal Production, 2010)
Lamb producers are being provided with strong incentives to gain better control over the growth performance of their animals. These incentives are driven by increased demand for lean product of consistent quality, rigid market specifications, and significant penalties when carcasses do not meet the criteria imposed by processors. Feed conversion efficiency is enhanced whenthe ratio of lean to fat deposition is improved (Sillence, 2004). This is an important consideration for producers due to rising costs of generating high quality feed. Hence, increasing the proportion ofcarcasses that meet market specifications can improve the profitability of a lamb-production enterprise.

Effect of white clover containing high or low concentrations of water-soluble carbohydrate on metabolic indicators of protein degradationin the rumen of dairy cattle - Higgs RJ; Cosgrove GP; Burke JL; Lane GA; Pacheco D; Fraser K; Death AF; Ford JL (Proceedings of the New Zealand Society of Animal Production, 2010)
White clover has high nutritive value, but contains excess protein relative to energy, leading to the wasteful excretion of nitrogen (N) by animals. Five cycles of divergent selection has resulted in white clover lines having high (HS) or low (LS) concentrations of water-soluble carbohydrate. A grazing trial was carried out to evaluate the effect of this selection on protein utilization, using skatole and indole concentrations in the milkfat as metabolic indicators for nitrogen utilisation in the rumen. Skatole and indole arise in the rumen from the degradation of the amino acid tryptophan, and rapidly accumulate in milkfat of lactating animals fed diets rich in soluble and degradable protein. Skatole and indole concentrations were both significantly (P <0.001) lower in cows fed HS clover (356 and 84 ng/g milkfat for skatole and indole, respectively) compared to those fed the LS white clover diet (800 and 420 ng/g milkfat, respectively) suggesting protein utilisation of the HS clover was improved. Although not statistically significant in this short-term study, the trends to lower concentrations of milk urea-nitrogen and urinary-N, and the nitrogen:creatine ratio for the HS clover were in the direction expected and warrant further investigation under longer-term feeding.

Effects of birth rank and yearling lambing on long-term ewe reproductive performance - Morel PCH; Wickham JL; Morel JP; Wickham GA (Proceedings of the New Zealand Society of Animal Production, 2010)
This experiment investigated the effects of differing nutritional levels on yearling pregnancy loss, and the live weight and survival of their offspring to weaning. Yearlings were offered either Medium or Ad-libitum levels of herbage from four days prior to breeding (P-4) until P145. Nutrition during pregnancy had no effect on pregnancy loss or lamb live weight from Day 0 of lactation (L0) until L55. Lambing percent was higher (P <0.05) in the Ad-libitum treatment compared to the Medium treatment. Single born lambs were heavier (P <0.05) than twin born lambs at L0 and at L55. Ad-libitum treatment yearlings were heavier (P <0.05) than Medium treatment yearlings at L55. Modelling of the live weight trends indicated that from P-4 until P145 the pregnant yearlings in the Medium and Ad-libitum treatment groups consumed 8.1 and 14.4 kg DM/kg of lamb live weight at L55. This indicates that the greater yearling live weight gain in the Ad-libitum group utilised more herbage during the yearling’s first winter without any increase in the performance of their offspring. The extra 9 kg gained by the yearlings fed Ad-libitum may have positive effects on future performance as they will gain a suitable live weight for breeding as a two year old earlier.

Effects of restricted fetal nutrition in utero on mTOR signaling in ovine skeletal muscle - Sciascia Q; Pacheco D; Bracegirdle J; Berry C; Kenyon PR; Blair HT; Senna Salerno M; Nicholas G; McCoard SA (Proceedings of the New Zealand Society of Animal Production, 2010)
High prolificacy (twins and triplets) is a desirable trait in sheep under intensive management systems. However, multiple-born lambs have lower birth weights resulting from placental insufficiency (McCoard, 1997), and carryover detrimental effects on lean deposition, feed efficiency, and lifelong performance compared to singletons (Greenwood et al., 1998; De Blasio et al.,2007), suggesting differential nutritional programming in utero.

Effects of road transport, including stationary periods on environmental conditions and physiological responses of sheep - Stewart M; JR Webster; Matthews LR; Rogers AR (Proceedings of the New Zealand Society of Animal Production, 2010)
Livestock transport exposes animals to challenging environmental conditions that can result in welfare compromise. During road transport, sheep can be exposed to a high temperature in combination with a high humidity, expressed as a temperature-humidity index (THI), that can lead to thermal stress (Fisher et al., 2002; Fisher et al., 2004). In practice, these conditions can result in mortalities. Lambs are particularly susceptible. Extreme conditions are more likely to occur on journeys where there is little air movement through the stock crates. For example, during an inter-island ferry crossing, when vehicles carrying livestock are parked inside the hull of the ferry rather than on the outside deck (Fisher et al., 2004).

The efficacy of a herbal drench treatment on internal parasites in lambs - Hutton P; Scott I; Schreurs NM; West DM (Proceedings of the New Zealand Society of Animal Production, 2010)
Internal parasites reduce live weight gains and are a cause of diarrhoea in growing lambs (Macchi et al., 2001). A challenge to organic sheep production is the control of internal parasites without intervention using synthetic chemicals. Whilst in conventional sheep production systems anthelmintic resistance to synthetic chemicals is increasing (Pomroy, 2006). The development of an effective herbal worm drench that can be commercialised will allow the organic sheep sector to develop and may offer an alternative for conventional systems.

Evaluation of sensors for monitoring rumen pH, temperature and pressure - Lin X; Pacheco D; Kemp PD; Waghorn GC; Cosgrove GP (Proceedings of the New Zealand Society of Animal Production, 2010)
Electronic intra-ruminal sensors and telemetry offer new opportunities for remote monitoring of the rumen environment. Sensors capable of measuring pH, temperature and pressure were subjected to laboratory and intra-ruminal evaluation in rumen-fistulated cows offered baleage indoors or hay with pasture outdoors. Each bolus underwent a testing sequence consisting of i) bench-top calibration against certified devices, ii) testing in the rumen to validate sensor measurement against actual measurement, and iii) monitoring the rumen environment of cows under contrasting feeding conditions for periods up to 72 hours. Bolus efficacy was evaluated from the accuracy of temperature and pressure measurements, stability of pH measurements over several days and the data capture rate being the actual number of data transmissions received as a proportion of the number expected based on transmission frequency setting. Intra-ruminal records show clear relationships of pH with diet and feeding bouts, whilst temperature records indicated drinking. Pressure changes were more difficult to interpret but may indicate satiety. These devices provide non-disruptive monitoring of rumen parameters and would be useful for studies of nutritional manipulation and rumen digestion efficiency, and for monitoring aspects of animal health.

Factors affecting dressing-out percentage of lambs - Litherland AJ; Dynes RA; Moss RA (Proceedings of the New Zealand Society of Animal Production, 2010)
The trial objective was to determine if hot carcass dressing out percentage (DO%) calculated as hot carcass weight/live weight, differed with either lamb pre-slaughter live weight (SlLW) or total tissue depth over the 12th rib (GR) and to identify other factors altering DO%. Data from ten experiments showed that SlLW only accounted for small, and measured GR moderate, amounts of variation in DO%. DO% was increased; by increasing the pre-slaughter fasting time; by increasing pasture allowance and by feeding more digestible forages such as clover, chicory or plantain versus grass based pasture. Similar trends occurred with the relationship between GR and DO%. At the same SlLW wether lambs had a lower DO% than female lambs but at the same GR there were no gender differences. At the same SlLW and GR, faster growing lambs had a lower DO%. While many factors significantly altered DO% including SlLW or GR, large amounts of variation in DO% remained unexplained.

Factors influencing gestation length and interval from foaling to conception in mares managed on a commercial Thoroughbred studfarm - van Rijssen JD; Gee EK; Rogers CW; O'Brien JR (Proceedings of the New Zealand Society of Animal Production, 2010)
The gestation length of mares is typically accepted as 335 to 342 days, but may range from 300 to 400 days. Most studies examining factors that may affect gestation length have been conducted in the Northern Hemisphere where foaling management may be markedly different from routine management in Australasia, where foaling takes place outdoors at pasture, and mares are kept at pasture year-round.

Genetic analysis of incidence of clinical mastitis in New Zealand dairy cattle - Jury K; Lopez-Villalobos N; Spelman RJ; Arias J; Heuer C (Proceedings of the New Zealand Society of Animal Production, 2010)
The aim of the study was to estimate breed and geneticeffects on the incidence of clinical mastitis (CM) in New Zealand dairy cattle. Records of CM collected during seasons 2005-06 to 2008-09 from 53,419 cows of different breeds including Holstein-Friesian (H-F), Jersey (J) and Crossbed (HF x J), were analysed. Clinical mastitis was coded “1” for cows that presented at least one event of CM at any day at risk during the season and “0” for cows without CM. Genetic parameters and breed effects for the incidence of CM were estimated with a repeatability animal model across breeds using restricted maximum likelihood methodology. The cumulative lactation incidence of CM was 11% in92,961 lactations. Heritability and repeatability for incidence of CM were 0.015 ± 0.003 and 0.070 ± 0.005, respectively. Jersey cowshad 2.9% less incidence of CM than H-F cows. Heterosis effect of H-F x J was minus 11.7% of the average of the parental breeds. Results from this study confirm previous estimates ofgenetic parameters for CM. Sire variation and breed and heterosis effects were significant and can be exploited in a breeding program to improve resistance to CM in New Zealand dairy cattle.

Genetic and environmental relationships between liveweight change over the summer in Perendale ewes and the lifetime live weight profiles of their progeny - Sumner RMW; Morris CA; Hickey SM; Sheppard AM (Proceedings of the New Zealand Society of Animal Production, 2010)
Multi-generation data from 1985 to 2002 were analysed from a 200-ewe Perendale flock to investigate genetic and environmental relationships between ewe pre-mating liveweight change and live weight of their progeny at birth, weaning, and 1, 2, 3, 4 and 5 years of age. The flock was managed at Whatawhata Research Centre and then at Winchmore Research Station, with selection for either increased or decreased wool bulk at one year of age. A total of 162 rams were used in a single-sire system. Numbers of resulting dam-offspring pairs ranged from 3,510 for progeny birth weights, to 369 for daughter 5-year-old live weights. Genetic and environmental correlations of progeny trait on dam trait, and the derived genetic (bG) and environmental (bE) regressions, were obtained from a restricted maximum likelihood animal model with a relationship matrix, after adjustment for known fixed effects. The bG estimates were all non-significant, with 14 of the 20 estimates tending to be negative. Three of the 20 estimates of bE were significant, with values ranging from 0.7 to 1.3% of mean progeny weight per kg dam gain. The estimated environmental relationships were of insufficient magnitude to impact on the flock’s productivity in the short term.

Identification of novel wool keratin intermediate filament genes in sheep skin - Yu Z-D; Gordon SW; Wildermoth JE; Wallace OAM; Nixon AJ; Pearson AJ (Proceedings of the New Zealand Society of Animal Production, 2010)
Keratin intermediate filament (KIF) genes encode key proteins for hair and wool formation. A total of 17 expressed human KIF genes involved in hair formation are annotated. However, to date, only eight wool KIF genes have been reported. In this study, six new cDNA sequences (KRT32, KRT33B, KRT34, KRT39, KRT40 and KRT82) representing previously unreported wool KIFs were identified using a contiguous ovine sequence library constructed primarily from ESTs. The expression of three other KIF genes (KRT36, KRT84 and KRT87) was confirmed by PCR using sheep skin total RNA. The analogue of human KRT37 (type I) was unable to be identified, while KRT87 (type II) was present in sheep but not in humans. Therefore 10 type I and seven type II KIF family members have been identified in sheep in comparison to 11 and six KIFs in the human. These 17 KIF genes are likely to represent the complete or near-complete set involved in wool formation. The annotation of these genes will facilitate investigation into their patterns of expression in wool follicles and their roles in the determination of fibre attributes.

Improving the power of activity-based heat detection using additional automatically captured data - Harris BL; Hempstalk K; de le Rue BT; Jago JG; McGowan JE (Proceedings of the New Zealand Society of Animal Production, 2010)
The purpose of this study was to determine the current performance of activity monitoring devices on New Zealand pasture-based farms and investigate the potential for improved detection using additional automatically captured data. The data consisted of heat events that were assigned from pregnancy diagnosis and mating records, and from milk progesterone levels collected twice weekly during mating period. Daily milk production, milking order, milk flow rate and milk conductivity records were also collected during the mating period. The best single predictor of oestrus was 24 hour milk yield difference (P <0.01) for Herd 1 and normalised milking order (P <0.01) for Herd 2. The normalised pedometer data was the next best predictor of oestrus in both herds (P <0.01). A linear logistic regression model was fitted within each herd. The best model included normalised milk production, milking order, milk flow rate and pedometer variables. Machine learning models with balanced bagging were also fitted to the data. The machine learning models provided a better fit than traditional statistical models. Pedometer data can aid in the detection of cow oestrus, however the power of detection improves significantly with the addition of milk yield, milk flow and milking order data.

Influence of conditioning temperature on pellet quality and the performance and nutrient utilisation of broilers fed maize- and sorghum-based diets - Abdollahi MR; Ravindran V; Ravindran G; Wester TJ; Thomas DV (Proceedings of the New Zealand Society of Animal Production, 2010)
Improved performance of broilers offered pelleted diets is thought to be due to improved nutritional value, decreased feed wastage, lowered energy expenditure during ingestion and decreased ingredient segregation (Behnke, 1994). The influence of pelleting, however, depends on the conditioning temperature used. While moderate thermal treatment of broiler diets improve the nutritional value, high conditioning temperatures can destroy vitamins and heat-labile amino acids, reduce the availability of starch by the formation of resistant starch and lower the availability of lysine through the Maillard reaction (Silversides & Bedford, 1999). Published data on the influence of conditioning temperature on the performance and nutrient utilisation of broilers are limited. The objectives of the present experiment were to compare the interaction between two grain-based diets and conditioning temperature on the performance and nutrient utilisation of broiler starters and on the quality of pellets.

Influence of management techniques on the levels of mastitis in an organic dairy herd - Thatcher A; Petrovski KR; Fraser K (Proceedings of the New Zealand Society of Animal Production, 2010)
n 2001, Massey University set up its Dairy Cattle Research Unit (DCRU) as a system comparison between organic and conventional farming. It is the only comparative grassland-based open grazing dairy study in the world. The DCRU was split into two similar farmlets; an organic unit of 20.4 ha carrying about 46 cows (2.27 cows/ha) and a conventionally farmed unit of 21.3 ha carrying about 51 cows (2.39 cows/ha). Each of the two units is managed individually according to “best practice” for its particular type of management system. No attempt is made to replicate on one farm what is done on the other. The project has been described in detail by Kelly et al. (2006).

The influence of sheep and cattle on the grazing preference of red deer - Foote SA; Nicol AM; Ridgway MJ (Proceedings of the New Zealand Society of Animal Production, 2010)
Two experiments examined the effect of sheep and cattle on the grazing preference of red deer. In the first experiment deer initially showed a significant (P <0.01) preference to graze on areas of ryegrass/white clover previously grazed for six weeks by cattle (77% of observations) rather than by sheep (23% of observations). However, 14 days later, deer grazing was equally distributed between cattle- and sheep-grazed areas (52% and 48% of observations respectively). In a second experiment deer, on pastures grazed by deer, showed no preference to graze close to cattle (48% of observations) or sheep (52% of observations). The strong but shortlived preference of deer for areas previously grazed by cattle cannot be explained by botanical composition, because although cattle-grazed areas contained a higher percentage of clover (22% with cattle, 16% with sheep), this difference was maintained for the later observation period when there was no difference in deer grazing preference. We conclude that any short-term preference shown by deer to graze with cattle rather than sheep is more likely to be due to their respective faeces/urine than their respective presence.

Influence of whole maize feeding on the performance of broiler starters - Singh Y; Wester TJ; Ravindran G; Ravindran V (Proceedings of the New Zealand Society of Animal Production, 2010)
Feed represents the major cost of poultry production, constituting up to70% of the total. Feeding of whole grains to poultry has received much attention in recent years as an alternative management practice to reduce the feed cost through savings in the cost of grinding and handling and processing of grains. This mode of feeding has not only shown positive effects on the performance but it also meets the consumer demands for a “natural” feeding system and improved animal welfare (Gabriel et al., 2007).

Intracellular concentrations of free amino acids are reduced in skeletal muscle of late gestation twin compared to single fetuses - Pacheco D; Treloar BP; Kenyon PR; Blair HT; McCoard SA (Proceedings of the New Zealand Society of Animal Production, 2010)
A cost-effective way toincrease productivity measured as kg lamb weaned per ewe, from sheep farming is to increase lambing percentage. However, late fetal and early neonatal twin lambs have reduced body weight (McCoard et al., 2000) and ~20% less skeletal muscle mass than singletons (McCoard et al.,2001) with carryover effects on post-natal growth performance (Afolayan et al.,2007; De Blasio et al.,2007), and thus profits. Increased knowledge of the impact of nutrition and other environmental factors on the mechanisms regulating fetal growth, in particular skeletal muscle growth, is essential in order to develop new strategies to enhance meat production performance.

Investigation of N isotopic fractionation in dairy cows using milk samples collected at the morning and afternoon milkings - Cheng L; Dewhurst RJ; Larkin J; Buckley F; Thackaberry C; Nicol AM; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2010)
Conversion of feed protein into milk protein is a basis of sustainable dairy production systems from both economic and environmental perspectives. This project addresses the need for rapid screening tools to support nutritional and breeding strategies to improve the efficiency of converting feed into milk protein. The approach is based on the phenomenon of N isotopic fractionation, whereby N sinks become relatively enriched or depleted in 15N, as a result of differential incorporation during various biochemical reactions. Macko et al. (1986) showed that N isotopic fractionation was related to the deamination and transamination of amino acids. Sick et al. (1997) conducted a feeding experiment with rats and found that plasma protein was enriched and plasma urea was depleted in 15N relative to the diet. Furthermore, Robbins et al

Jim Peterson: – A career in reproductive biology - Back P; Smith JF; Welch RAS; Macmillan KL; Ledgard AM; Peterson AJ; Tervit HR (Proceedings of the New Zealand Society of Animal Production, 2010)
Our collaboration was both long and successful with a total of 39 publications as co-authors over a period of 32 years. Our first paper was in 1973 and our last in 2005. The collaboration was successful because it combined Jim’s unique and pioneering ability to develop hormone assays with my knowledge and experience in reproductive physiology. It resulted in a number of seminal papers containing new knowledge that was then used by workers nationally and internationally to increase the understanding of hormones, their effects and interactions.

Lack of effect of hot summer conditions in Canterbury on milk production of dairy cows - Laird FC; Barrell GK (Proceedings of the New Zealand Society of Animal Production, 2010)
The occurrence of hot weather in Canterbury over 90 days during the 2008/2009 summer provided an opportunity to investigate the effects of climatic heat challenge on milk production by cows on commercial dairy farms in that region. An analysis of daily milksolids production and the peak temperature-humidity index (THI) recorded on each previous day was conducted for 13 farms in mid-Canterbury using data from 1 December 2008 to 28 February 2009. There were 19 days when dry bulb air temperature exceeded 27°C and the THI was 72 or higher, conditions at which heat stress has been suggested to occur in dairy cows. However, there was no significant inverse relationship between THI and milksolids production (P ranged from 0.193 to 0.897) on any of the farms using either all the data or only the data for days on which THI exceeded 72. With relative humidity being strongly inversely related to dry bulb temperature in Canterbury summers, THI values rarely exceed 75 in this region. As there were no discernable effects on productivity of these dairy cows during the episodes of hot weather, it is also unlikely that there would be any animal welfare concerns that could be attributable to climatic heat challenge in these conditions.

Management and exercise of Thoroughbred yearlings during preparation for yearling sales in the North Island of New Zealand - Bolwell CF; Rogers CW; Firth EC; French NP (Proceedings of the New Zealand Society of Animal Production, 2010)
A cross-sectional survey was conducted to describe the management and exercise regimen at stud farms during preparation for the 2008 national yearling sales. A total of 1,166 yearlings were included in the survey, representing 82% of those offered at the Karaka sales in 2008. Ninety-two percent of farms (69/75) used a combination of both pasture turnout and stabling during yearling preparation, with most farms (47/75; 63%) giving yearlings access to pasture for >12 hours per day. Controlled exercise was performed on 80% (60/75) of stud farms, with most (54/60; 90%) farms exercising at walk. Management practices appeared to be relatively homogeneous across the farms surveyed. The provision of free exercise at pasture and controlled exercise were common practices during a sales preparation.

Marbling produced in yearling heifers of Angus origin finished over a medium-term period on a high energy pasture - Wall AJ; Rosenvold K; Archer JA; Dobbie P; Scott I; Stevens DR; Littlejohn RP (Proceedings of the New Zealand Society of Animal Production, 2010)
This study provides baseline information on the level of marbling that can be produced from yearling heifers of Angus origin when finished over a medium-term, 169 day, period on a high energy pasture. Two groups of heifers were tested, which included 30 Angus x Jersey heifers and 26 straight-bred and cross-bred (mainly Hereford x and Friesian x) Angus heifers. The daily live weight gain of the heifers during finishing averaged 788 g/d and did not differ between the two groups of heifers studied (P >0.05). At slaughter, the carcass weights of the Angus x Jersey heifers were lighter than the group of straight-bred and cross-bred Angus heifers (P <0.05). Nevertheless, both groups produced average striploin marbling scores of 2 on the Japanese Meat Grading Association 12 point scale (P >0.05), with 39% of the cattle achieving scores ≥2. The high level of variability in marbling across both groups of heifers indicated that the average level of marbling achieved could be further improved by using some predictor of marbling performance to select animals to be finished in the pasture-based system. All of the heifers produced very tender beef with average shear force values <5 kg F.

Measurement of sole thickness and distance to distal phalanx using a portable ultrasound machine - Laven LJ; Margerison JK; Laven RA (Proceedings of the New Zealand Society of Animal Production, 2010)
Using a high specification ultrasound machine, with the ultrasound transducer applied to the sole surface, Kofler et al.(1999) were able to estimate sole and soft tissue thickness in claws from bovine cadavers. These ultrasound estimates were significantly correlated with measurements, made using mechanical callipers,of the same parameters in claws after sectioning. Moreover, Kofler et al.(1999) demonstrated that it was possible to image the internal structures of the bovine claw in the live animal and also reported the use of a portable ultrasound. They did however state that the images were of lower quality, due to the poorer resolution of the transducer, and were more difficult to obtain. In contrast, van Amstel et al.

Methods of delivering salt to cattle - Costall DA; Betteridge K (Proceedings of the New Zealand Society of Animal Production, 2010)
Urine from farmed livestock contributes significant quantities of nitrate nitrogen (N) to water bodies, resulting in elevated phytoplankton and nuisance plant growth. Heavily nitrate-contaminated groundwater can impair animal and human health. Ammonia and nitrous oxide also emit from urine patches, especially in anaerobic soil conditions (Ledgard and Luo, 2008). Several N leaching mitigation treatments are being evaluated in the Lake Taupo catchment (Ledgardet al., 2007) with salt, fed as a diuretic to cows during winter, showing most promise in modelling research (Bryantet al., 2007). This is probably because leaching losses from urine patches decrease exponentially as the load of N in urine patches decreases (Ledgard, 2001).

Milestones in genetic prediction for applied livestock improvement - Garrick DJ (Proceedings of the New Zealand Society of Animal Production, 2010)
Realised rates of genetic improvement depend upon structural, technological, economic and cultural factors. The potential nature and rate of genetic improvement of livestock has largely been dictated by accuracy of the predicted genetic merit of selection candidates. Major milestones in predicting merit include the use of objective measurements rather than visual appraisal; adjustment of measured performance for nongenetic factors; use of aggregate measures of economic merit for multiple trait selection; combining of information from all available sources of relatives and traits; and properly accounting for previous selection. Despite these advances, use of pedigree and performance information has major limitations. Genomic technologies can trace inheritance of chromosome fragments and with knowledge of the fragment values can improve accuracy of prediction in young selection candidates. Current genomic methods perform more poorly with real than with simulated data, and predictive abilities erode when applied to target animals not closely related to the population used to quantify fragment values. Several strategies are being investigated to improve genomic predictions, but in the meantime the principal benefit of the technology has been to increase accuracy of predicted merit of young selection candidates for routinely measured traits. In some cases this has reduced the generation interval.

Natural variation in levels of Immunoglobulin A in bovine milk - Carpenter EA; Hurford DR; Hickey SM; Morris CA (Proceedings of the New Zealand Society of Animal Production, 2010)
Bovine milk has been reported to contain low levels of Immunoglobulin A (IgA) in comparison to human milk (0.1 g/L vs 1.0 g/L, respectively) (Butler, 1999). However, analysis of milk collected from cows vaccinated to induce antigen-specific IgA secretion in milk (Hodgkinson, et al., 2007) has demonstrated that the IgA response of individual cows is variable, with a ~10-fold range in the IgA production by individual vaccinated cows at peak lactation (E.A. Carpenter, Unpublished data). Approximately 10% of these cows are classified as “high milk IgA producers”, defined by Wagter et al.(2000) as those cows with a milk IgA concentration greater than one standard deviation above the group mean.

On-farm ewe lamb mating outcomes from feeding practices before mating and during pregnancy - Stevens DR (Proceedings of the New Zealand Society of Animal Production, 2010)
Farmers in southern New Zealand identified areas where knowledge was needed to improve the outcomes from mating ewe lambs at seven months of age. Anecdotal evidence suggested that ewe lambs growing rapidly at mating were less likely to become pregnant. Farmers recorded ewe lamb live weight in March and late May, and pregnancy diagnosis data. Data analysis showed no relationship between liveweight gain and number of ewe lambs pregnant. Farmers retained their original views that liveweight gain before and during mating should be below 100 g/d. Feeding levels in late pregnancy were considered to influence ease of lambing and lamb survival. The amount of feed offered to ewe lambs in late pregnancy on eight farms was compared to tailing percentage and lamb mortality. Feed offered to single bearing ewe lambs in late pregnancy ranged from 0.75 to 1.6 kg dry matter/d. Late pregnancy feed allowance and lamb mortality were unrelated. Analysis of winter liveweight gain data from both on-farm studies and survey results over two years showed that winter liveweight gains of 10 to 14 kg, including conceptus weight, minimised lamb losses (P <0.05). Farmers changed management practices to improve winter liveweight gain, and improve the accuracy of late pregnancy feed allocation.

An overview of the New Zealand Thoroughbred industry - Fennessy PF (Proceedings of the New Zealand Society of Animal Production, 2010)
The New Zealand thoroughbred industry is internationally-competitive in terms of performance; however, the current economic situation means that the foal crop is declining. Stakes have increased in recent years but increasing costs that are common to all primary industries are also a key issue for the breeding and racing industry.

Phenotypic relationship between milk protein percentage and reproductive performance in three strains of Holstein Fresain cows in Ireland - Yang L; Lopez-Villalobos N; Berry DP; Parkinson T (Proceedings of the New Zealand Society of Animal Production, 2010)
The relationship between milk protein percentage and fertility in seasonal calving, dairy cattle in Ireland was quantified using a total of 584 lactation records, collected over a five-year period from experiments comparing three strains of Holstein-Friesian cows under three different feeding systems. Logistic regression analyses showed that increased protein percentage during early lactation was positively associated with the probability of a cow becoming pregnant to its first service (P <0.05). Similarly, protein percentage during the lactation had a positive (P <0.01) association with overall pregnancy rate. The results suggest that negative energy balance in early lactation or during the whole lactation causes a shortage of glucose to the udder, this restricts the synthesis of milk protein in the udder and causes a lower milk protein percentage. During negative energy balance there is also a concurrent reduction of IGF-І, LH and oestradiol secretion, which consequently delay ovarian follicular development, and hence impairs reproductive performance. In conclusion, cows with higher milk protein percentage during early lactation have a greater likelihood of becoming pregnant earlier in the breeding season, and have a higher conception rate.

Potential benefits of low replacement rate for dairy herd production and profit - Lopez-Villalobos N; Holmes CW (Proceedings of the New Zealand Society of Animal Production, 2010)
The effects of different replacement rates on the genetic gain for lactation yields of milk and milksolids (fat + protein) per cow and farm profit per hectare were evaluated using a simulation model. Three levels of replacement rate were simulated 15, 19 and 27%, by varying the levels of involuntary culling, such as with low fertility, and voluntary culling based on production worth. The effect of selection of replacements based on breeding worth was also evaluated. In the base year, farm profit was higher for lower replacement rates. Annual genetic gain in average herd breeding values for milksolids after 20 years of using bulls of high breeding worth was higher at higher replacement rates. However, farm profit at Year 20 was still higher for a herd with a low replacement rate than for a herd with a high replacement rate. A herd with a 15% replacement rate in combination with selection of replacement heifers based on breeding worth, achieved the highest gain in breeding values for milksolids and achieved the highest farm profit at Year 20. These results demonstrate that low replacement rate in combination with selection of high breeding worth heifers can achieve high genetic gain in both milksolids and farm profit.

Prediction of herbage dry matter intake for dairy cows grazing ryegrass-based pastures - Baudracco J; Lopez-Villalobos N; Holmes CW; MacDonald KA (Proceedings of the New Zealand Society of Animal Production, 2010)
A model that combines theoretical and empirical equations was developed to predict daily dry matter intake (DMI) for Holstein-Friesian (HF) cows grazing ryegrass-based swards and offered differing levels of concentrate supplementation. An upper limit to potential herbage dry matter (DM) intake at grazing was set, which is the lower of three limits set by either physical (rumen fill), metabolic (energy demand) or grazing restrictions. Potential herbage DMI at grazing and the herbage allowance were then used to predict herbage DMI, of cows fed only pasture, using an empirical algorithm. If supplements are fed, substitution rate was predicted to calculate actual herbage DMI. An independent dataset, with individual herbage DMI measurements (n = 1,147) of three strains of lactating HF cows, was used to validate the model. Data within strains were averaged for every month of lactation, allowing 27 data points for validation. The fitness of the model was satisfactory, with a relative prediction error (RPE) of 0.083 and a concordance correlation coefficient (CCC) of 0.74. Herbage DMI was simulated for HF cows of different genotypes fed different levels of concentrate supplementation at different herbage allowances. The model successfully predicted herbage DMI of grazing cows under different combinations of nutritional, physiological and genetic variables.

Preference of lambs for novel pasture herbs - Pain SJ; Hutton PG; Kenyon PR; Morris ST; Kemp PD (Proceedings of the New Zealand Society of Animal Production, 2010)
There is strong evidence that sheep show a preference for some plant species over others (Parsons et al.,1994; Concha & Nicol, 2000; Foster et al., 2002; Rutter, 2006; Corkran, 2009). Differences among ruminant species in forage selectivity, offers a unique opportunity to manipulate utilization of pastures. Recently, increased milk yields and higher weaning weights of lambs have been shown to occur, when grazing a mixed herb sward containing chicory (Cichorium intybus), red and white clover (Trifolium pratenseand T. repens) and plantain (Plantago lanceolata) (Golding, 2008).

Preliminary examination of sport horse competition data for genetic evaluation - Creagh FE; Hickson RE; Rogers CW (Proceedings of the New Zealand Society of Animal Production, 2010)
A sport horse can be defined as a horse which participates in one of the three equestrian disciplines represented at Olympic level. These disciplines are dressage, eventing and show jumping. There are approximately 5,000 horses registered for equestrian sport in New Zealand (Rogers & Firth, 2005). Despite the relatively small size of the New Zealand equestrian sport population, the New Zealand industry has been successful in International sport with the production of predominantly show jumpers and event horses for the export market (Rogers, 1993; Rogers & Firth, 2005).

Preliminary investigation of milk production in Angus heifers exposed to different nutrition in utero - Peterson SW; Jenkinson CMC; Hickson RE; Morris ST; Blair HT; Kenyon PR (Proceedings of the New Zealand Society of Animal Production, 2010)
Milk yield (MY) and composition were measured on one day in Weeks 7, 9 and 11 in 17 offspring of Angus cows fed for high (1.2 kg/d; HB) or medium (0.5 kg/d; MB) liveweight gain (LWG) for 10 days before insemination and medium (0.5 kg/d; MA) or low (0.01 kg/d; LA) LWG during gestation. Mean MYs in the progeny were; Week 7: 5790 ± 420 g/d, Week 9: 7418 ± 447 g/d, Week 11: 6244 ± 392 g/d. Better feeding before mating had little effect on MY or milk crude protein (CP%) in the progeny but tended to reduce the milkfat% (Week 9; HB (n = 8) 3.50 ± 0.17% versus MB (n = 8) 3.74 ± 0.22%) (P <0.19), casein (Week 11; HB 2.59 ± 0.03% versus MB 2.68 ± 0.04%) (P = 0.11) and lactose (Week 11; HB 5.18 ± 0.13% versus MB 5.42 ± 0.05%) (P = 0.075). Better feeding of the dam after artificial insemination did not significantly increase MY of the progeny (Week 9; MA (n = 9) 7972 ± 378 g/d versus LA (n = 8) 6794 ± 826 g/d) (P = 0.23), or milkfat%, decreased CP (Week 9; MA 3.22 ± 0.07% versus LA 3.41 ± 0.08%) (P <0.09) and casein% (at Weeks 7 and 9 identical values of MA 2.52 ± 0.06% versus LA 2.69 ± 0.07%), but increased lactose% after the peak of lactation (Week 11 MA 5.42 ± 0.06% versus LA 5.15 ± 0.14%) (P <0.08). Feeding before and after conception may affect the nutrition of the grand generation

Preliminay examination of training and racing milestones in a subset of Standardbred horses - Tanner JC; Rogers CW; Bolwell CF (Proceedings of the New Zealand Society of Animal Production, 2010)
The Standardbred (harness racing) industry is the second largest equine industry in New Zealand. In 2004 it had a total contribution to the country’s gross domestic product of $327 million (IER, 2004). Of the 22 countries that participate in harness racing, New Zealand is ranked tenth based on the number of individual horses to race per season, and on the number of races run per season (Harness Racing New Zealand, Personal communication). However, despite the economic contribution of the Standardbred industry in New Zealand there has been little documentation of the structure and demographics.

The prevalence of limb deformities in New Zealand Standardbred foals and the influence on racing success - A preliminary investigation - Stowers NL; Erdtsieck B; Rogers CW; Taylor TB; Firth EC (Proceedings of the New Zealand Society of Animal Production, 2010)
Within the New Zealand racing industry, breeders and purchasers of racehorses seek foals with good conformation as racing and breeding prospects. There is a perceived association between correct conformation and the duration and success of racing careers (Welleret al., 2006a). However, to date there has been limited data on the effect of limb deformities on any parameters of racing success (Morley & Townsend, 1997, Andersonet al., 2004).

Productive and reproductive performance of Uruguayan Holstein and Urugyayan Holstein x New Zealand Holstein Friesian cows in a predominantly pasture-based system - Periera I; Laborde D; Carriquiry M; Lopez-Villalobos N; Meikle A (Proceedings of the New Zealand Society of Animal Production, 2010)
The performance of Uruguayan Holstein (UH) and UH x New Zealand Holstein Friesian first cross (UHNZHF) cows was investigated over 1 year using 62 cows offered predominantly native pasture. Accumulated 305 day yields of milk, fat, protein and milksolids (fat+protein) were not affected by the strain. The UH cows produced 0.5 L/d more milk than UH-NZHF cows at Day 240 of lactation (P <0.05). Fat and lactose percentages were greater in UH-NZHF cows (3.72 vs 3.44% and 5.02 vs 4.94%, respectively, P <0.0001). Protein percentages tended to be greater in UH-NZHF cows (3.31 vs 3.27%, P = 0.08). The UH cows were 49 kg heavier (569 vs 520 kg, P <0.001) and required a greater energy requirement for maintenance. The UHNZHF cows produced more milksolids per kg of BW0.75, (P <0.01). Pregnancy rates tended to be greater in UH-NZHF cows (87 % vs 71%, P = 0.08) and were greater when the first 40 days of service were considered (61 vs 35%, P = 0.04), which may be related to a differential energy partitioning according to strains.

Review of pork-quality studies in New Zealand - Morel PCH; Purchas RW; Wilkinson BHP (Proceedings of the New Zealand Society of Animal Production, 2010)
This paper presents data published between 1990 and 2009 on pork quality in New Zealand. The characteristics considered are pale, soft and exudative (PSE), dark firm and dry (DFD), boar taint, intramuscular fat (IMF%), chemical composition aspects such as fatty acids profile and flavours other than boar taint. Over the years the incidence of PSE has been reduced from 40% to 6%. The percentage of DFD pork was always below 7%. A level of 2.0% of IMF% is considered as a minimum with respect to palatability. Between 1990 and 2009, reported values for IMF% ranged from 0.98% to 3.36% and tended to decreased over time. Skatole and androstenone are the two major compounds responsible for boar taint. In New Zealand, males are slaughtered “entire”. In 1996 only 19% of them were below the European Community threshold for boar taint. Results from different feeding experiments show that the fatty acid profile, selenium content and flavours other than boar taint, of pork can easily be changed. Overall pork from New Zealand pigs is of a high quality, but the incidence of boar taint is of concern.

Role of the New Zealand Society of Animal Production in fostering collaboration - Archer JA (Proceedings of the New Zealand Society of Animal Production, 2010)
When you sign up for a year as President of the New Zealand Society of Animal Production, you should make an attempt to understand who the Society really is, and how the members are best served by the Society. If you go back through previous Presidential Addresses some recurring themes come up around this issue of who is the Society Membership and what should the Society be doing to best serve the membership? The fact that we frequently re-visit this question shows that it is pertinent. It also proves the words of Abraham Lincoln true when he said “Books serve to show a man that those original thoughts of his aren’t very new at all”

Ryegrass to lucerne-effects of dietary change on intake,milk yield and rumen microflora bacteria of dairy cows - Woodward SL; Waghorn GC; Attwood GC; Li D (Proceedings of the New Zealand Society of Animal Production, 2010)
The value of legumes for milk production has been attributed to higher intakes by cows and a higher nutritive value compared to ryegrass. However, abrupt changes in diet can adversely affect production, even when the change is to feed with a higher feeding value. A 13-day indoor experiment compared the responses of 12 cows that were changed from ryegrass to lucerne (Medicago sativa L.) (L) on Day 4, with 12 cows remaining on ryegrass (R). Immediately after the change to lucerne there was a 24% decrease in milk yield; this was temporary, as from four days after the change these cows averaged 20% more milk than those fed ryegrass (L = 15.7, R = 13.1 kg milk/cow/d; P <0.001). The temporary decrease in milk yield was not due to decreased intake as lucerne-fed cows had higher intakes (L = 16.5, R = 14.8 kg dry matter/cow/d; P <0.001). Only small differences in the rumen microbial populations were apparent on the day diets changed. The temporary decrease in milk yield was more likely associated with a change in metabolism of the resident bacteria. Improved understanding of the microbial consequences of an abrupt dietary change will enable better management decisions to be made on-farm.

Simulated impacts of increased nitrogen retention in dairy cows on nitrate leaching from grazed pasture - de Castro J; Bryant JR; Burggraaf VT (Proceedings of the New Zealand Society of Animal Production, 2010)
The intensification of grazing land has increased the amount of nitrogen (N) entering waterways, reducing their quality and clarity. Between 60 and 90% of the N ingested by grazing cattle is excreted in urine and dung (Haynes & Williams, 1993), providing the major source of nitrate leached from grazed pasture. Reducing the N content of urine can therefore have a major impact on nitrate leaching, which can be achieved by reducing dietary N or improving N partitioning in the animal. Some techniques that improve N partitioning have been evaluated. These include dietary manipulation and the use of metabolism modifiers (Di & Cameron, 2000).

Suitability of the Happy Factor decision support model as part of targeted selective anthelmintic treatment in Coopworth sheep - Greer AW; McAnulty RW; Logan CM; Hoskin SO (Proceedings of the New Zealand Society of Animal Production, 2010)
The suitability of the Happy Factor decision support model as the determinant of a targeted selective treatment regime incorporated into an automated weighing and drafting facility was evaluated in a Canterbury environment. One hundred and twenty, six-month-old Coopworth lambs naturally infected with gastrointestinal parasites were weighed and faecal sampled every two weeks for eight weeks. Individual performance targets during each two week period were calculated using the Happy Factor decision support model. Lambs that did not reach their performance target were automatically drafted out and subsequently treated with anthelmintic. Those deemed to benefit from treatment had significantly greater faecal egg count (FEC) than their untreated counterparts at Week 4 only, were lighter on Weeks 2 and 8, but had lower liveweight gains on all four occasions. Overall, the system provided a rapid and reliable method of identifying and separating poorer performing individuals, which were not necessarily those with a high FEC or those that were lighter. Furthermore, the optimum treatment threshold was determined to be 0.74, which is greater than previously published values of 0.66 for Scottish Blackface sheep. This suggests that validation of an optimum Happy Factor treatment threshold for each environment and/or animal genotype may be required.

Use of novel pasture species to reduce methane emissions from New Zealand grazing ruminants - Roca FJ; Hutton PG; Pain SJ; Kenyon PR; Morris ST (Proceedings of the New Zealand Society of Animal Production, 2010)
In New Zealand, methane (CH4) accounts for approximately 38% of greenhouse gas emissions. The majority of this methane, approximately 98%, is from ruminants (Waghorn & Woodward, 2006). New Zealand’s ruminant production industry relies heavily on a pasture-based system and depends on efficient utilisation of pasture. Variation between plant species in their nutritional and chemical composition provides an opportunity to manipulate rumen fermentation patterns and increase the utilization of pastures, while potentially reducing ruminant livestock CH4emissions. Preliminary findings are reported from a pilot study which investigated the effects of nutritional composition of a range of forage species on the short-term in vitro production of CH4.

Variation in feed conversion efficiency in Holstein-Friesian heifer calves - Carnie KR; Davis SR; MacDonald KA; Waghorn GC; Obolonkin VV; Spelman RL (Proceedings of the New Zealand Society of Animal Production, 2010)
Feed conversion efficiency (FCE) is a measure of an animal’s ability to convert feed into product and is a major determinant of profitability in livestock production. This study evaluated two determinants of FCE in Holstein-Friesian heifer calves, growth rate and residual feed intake (RFI). The improvement in FCE, measured as feed intake per unit of liveweight gain (kg/kg), associated with increased growth rate is well known (see Archer et al., 1999). It is measured when the energy costs of maintenance are relatively small compared to the energy intake that is partitioned into growth of animal tissues or lactation.

Wool characteristics in the Meat and wool New Zealand Central Progeny Test flocks - Craven AJ; Ashby MG; Scobie DR (Proceedings of the New Zealand Society of Animal Production, 2010)
The Meat and Wool New Zealand Central Progeny Test programme (CPT) was established to demonstrate the relative breeding merit of leading sires in the New Zealand sheep industry. Here we describe the wool grown over the summer by the 2007 born one-year-old ewes within the CPT. Within fleeces, staple strength varied between farms as shown by the mean difference of 23 N/ktex in offspring of the link sire. Staple strength correlated positively with midside fibre diameter (r = 0.26), medullation (r = 0.23) and negatively with fibre curvature (r = -0.61). Staple strength was similar on anterior (74 ± 24 N/ktex) and midside (75 ± 24 N/ktex) body-sites, but was weaker on the hindleg (64 ± 21 N/ktex; P <0.001). Overall mean staple strength was 72 ± 20 N/ktex, while individual fleeces ranged from 19 to 121 N/ktex. Ten percent of fleeces measured below 45 N/ktex leaving them prone to excessive fibre breakage during processing. Some fleeces varied up to 40 N/ktex across body-sites. Even within one flock, offspring of individual sires differed by a mean of 29 N/ktex, suggesting a consistent weakness of wool in the progeny of some highly ranked sires which will negatively affect processing and end-product performance.

Yearling lambing performance and primary cause of lamb death - Young EA; Yuan JV; Everett-Hincks JM (Proceedings of the New Zealand Society of Animal Production, 2010)
As a result of increasing on-farm costs, farmers are aiming to increase the number of saleable lambs by lambing yearling ewes. This study investigated lamb survival rates in lambs born to yearlings from birth to three days of age. Data were collected from six recorded flocks in 2007 and 2008, involving 880 yearling ewes giving birth to 557 single and 756 twin lambs. All lambs were weighed at birth and at weaning. Lambs that died within the first three days of life were subject to post-mortem to determine the primary cause of death. Mean lamb survival to three days of age was 80% and survival to weaning was 72%. There were significantly less twin lambs born alive, than single lambs (90%, CI 88% - 92%, cf. 95%, CI 93% - 96%, P <0.05). Twin lambs had a higher death rate due to starvation/exposure, (6.3%, CI 5.3% - 7.4% cf. 2.8%, CI 2% - 3.8%, P <0.05) than single lambs. Dystocia did not differ significantly between single and twin lambs (6% cf. 10% respectively; P >0.05). Mortality in the first few days after birth is higher in yearlings than in flock ewes and higher in twins than singles.

Amino acid flow at the abomasum in twin-suckling ewes at pasture and the effect of a fishmeal supplement - Madibela OR; Gibbs SJ; Sykes AR; Laporte-Uribe J; Zhao J (Proceedings of the New Zealand Society of Animal Production, 2009)
Fourteen twin-suckling ewes with rumen and abomasal cannulae grazed a ryegrass/clover sward (C; n = 7) or the same sward but with a 500 g/h/d protein supplement (S; n = 7). The trial was designed as a cross-over with two 14 day adaptation periods followed by two five day sampling periods (Days 43-48 and 63-68 after lambing). All ewes were treated with anthelmintic 14 days after lambing. Flow of amino acids (AA) at the abomasum and dry matter (DM) intake were measuredduring both periods using intra-ruminally infused markers. Diurnal variation in AA flow peaked between 12:00 and 15:00 h and was greatest in the supplemented ewes. Flows of AA were increased by supplementation; Essential AA, +16 %; 128 to 148 g/d, Sulphur-AA, +21.2 %; 3.3 to 4.0 g/d, Branched-chain AA, +15.9%, 47.8 to 55.4 g/d. There was evidence for a lower faecal egg count in supplemented animals, being 670 vs 46 epg, respectively, in C and S groups, (P = 0.08) 21 days after anthelmintic treatment. This work provides information on the extent of enhancement of the supply of amino acids associated with ability to limit the peri-parturient increase in faecal egg count and provides a basis for the development of supplements.

Background effects on ewe lambing and weaning performance in well recorded breeding flocks - Amer PR; Sise JA; Jopson NB; Bray AR (Proceedings of the New Zealand Society of Animal Production, 2009)
Results of analyses of Sheep Improvement Ltd. (SIL) data (27 flocks and 128,203 lambings) showed a substantial impact of ewes being scanned pregnant but failing to rear a lamb (wet-dry), on weight of lamb weaned at the next lambing. Compared to ewes that reared a lamb at the previous lambing, 'wet-dry' ewes had 0.3 to 0.5 less lambs born per ewe lambing, lamb survival rates were lower by 60 to 70 percentage points and weaning weights up to 0.5 kg lighter per lamb weaned. These effects compounded into 30 to 40 kg less weight of lamb weaned per ewe. The failure to rear part of a litter, such as one lamb of a set of twins, had less effect on performance at next lambing and weaning, than loss of the whole litter. Those ewes that previously gave birth to three lambs weaned 4 kg less lamb weight than ewes that previously gave birth to singles, after allowing for their higher genetic drive for prolificacy. A modest but significant effect of previous litter size was observed on weight of lamb weaned within each litter size category. Lamb survival was observed to be 2% lower (P <0.01) for twin ewes that had failed to rear one of their two lambs, compared with those that had reared both in their previous lambing.

Bioactive plants inhibit bacteria that cause lactic acidosis in ruminants : Brief Communication - Hutton P; Durmic Z; Ghisalberti E; Duncan R; Carson CF; Riley TV; Vercoe PE (Proceedings of the New Zealand Society of Animal Production, 2009)
Lactic acidosis may become an animal welfare issue in New Zealand if the level of concentrates used in the feed ration increases. Lactic acidosis develops in ruminants because of the excessive production of lactic acid by starch degrading bacteria in the rumen after animals are introduced to grain–based diets containing large amounts of starch. It is important that lactic acid is converted to volatile fatty acids in the rumen rather than being absorbed into the bloodstream. Rumen bacteria that ferment starch to lactic acid are capable of rapid cell reproduction and, when starch is freely available, produce lactic acid at a higher rate than lactate is fermented to volatile fatty acids by lactate-using bacteria.

Breed effects for lactoferrin concentration determined by Fourier transform infrared spectroscopy - Lopez-Villalobos N; Davis SR; Beattie EM; Melis J; Berry S; Holroyd SE; Spelman RJ; Snell RG (Proceedings of the New Zealand Society of Animal Production, 2009)
A calibration equation based on partial least squares using Fourier transform infrared spectroscopy (FTIR) data was derived to predict concentration of lactoferrin (Lf) in bovine milk. The concordance correlation coefficient of the calibration equation was estimated at 0.81 using 246 milk samples collected in the 2003-04 season from second-parity crossbred cows during late lactation. The calibration equation was then used to predict the concentration of Lf (pLf) in 9,742 milk samples from 814 Holstein-Friesian (HF), 955 Jersey (J) and 842 crossbred HF x J cows sampled on average 3.7 times during the 2007-08 season. A repeatability animal model was used to obtain breed effects and estimates of variance components for pLf. Concentrations of pLF (mg/L milk) were significantly (P <0.001) different between breed groups (HF = 163 ± 3.8, HF x J = 175 ± 5.0 and J = 193 ± 6.3). Heritability and repeatability of pLf concentration were 0.16 ± 0.036 and 0.35 ± 0.012, respectively. These results confirm previous studies showing that Lf concentration in milk can be predicted using FTIR spectroscopy and that there are significant breed differences and animal variation that can be exploited in a breeding program.

Breeding and selection goals and animal welfare - Fisher MW; Webster AJF (Proceedings of the New Zealand Society of Animal Production, 2009)
Contemporary concerns with animal welfare are increasingly being expressed through reference to the Five Freedoms, paraphrased as animal needs. However, in addition to providing for the needs of livestock, breeding animals to suit the environment, especially in extensive farming systems, is an inherent quality of good stockmanship. Although most farm animal breeding goals are directed at increasing productivity, some, for example resistance to disease or ease of giving birth, also contribute to enhanced animal health and welfare. Increasingly societal expectations are shaping the practices of animal rearing and management, and more recently breeding. It is suggested that those responsible for breeding and selection acknowledge the potential animal health and welfare consequences, both positive and negative, of breeding goals. In so doing that they be prepared for the need to articulate those goals in terms of animal health and welfare, or the need for relevant animal husbandry skills and resources. Subsequently, where necessary they incorporate animal welfare objectives into their breeding programmes. In addition, animal welfare interests need to be aware of the limitations of relying solely on the Five Freedoms, or needs of animals, and acknowledge the wider aspects of good animal husbandry which contribute to animal welfare.

Current and future impact of DNA technologies on the New Zealand sheep industry - McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2009)
DNA technologies are already widely used in the New Zealand sheep industry. Parentage determination in extensively managed flocks is currently the most widely used test. Increasingly, these tests are being supplemented by the use of performance markers, either by themselves or in conjunction with parentage. Commercial single marker tests currently available in New Zealand include: two for meat yield, two for prolificacy, parasite resistance and production, lamb survival, footrot, scrapie susceptibility, and several monogenic trait tests including: microphthalmia, horns, and spider lamb. However, the future is likely to be some form of 'genomic selection' where the test explains a major, perhaps majority, of the genetic variation in an animal. This technology depends on the creation and use of high density SNP (single nucleotide polymorphism) probe chips. In New Zealand dairy cattle it is expected to increase the rate of genetic gain by 50 to 70%. A similar chip has been created for sheep and New Zealand animals are currently being genotyped. If successful the expectation is that industry release will occur in late 2009. New Zealand sheep industry delivery will be as breeding values created using a blend of DNA and existing Sheep Improvement Ltd. information.

Dairy cows and horses do not select oaten hay based on its greenness : Brief Communication - Pain SJ; Revell DK (Proceedings of the New Zealand Society of Animal Production, 2009)
Domestic and export markets for oaten hay are driven largely by estimates of the quality of hay produced. This assessment is commonly based on the plant of origin and subjective criteria, such as colour, or 'greenness', and general appearance as judged by an observer. However, subjective measures such as these are not always reliable indicators of an animal's response to a hay when offered, in terms of its intake and ultimate performance. Understanding the role of specific plant characteristics that... Continued

Delaying the time of morning grazing improves milk production in winter - Acosta GA; Rossi JL; Ayala Torales A; Acosta A (Proceedings of the New Zealand Society of Animal Production, 2009)
Herbage dry matter content and water-soluble carbohydrate influence cow intake and production. Delaying the time of grazing may increase the dry matter and water-soluble carbohydrates content of herbage and increase grass consumption and milk production. This study determines the cow response to early (8:00 h) and late (11:30 h) offer of winter pasture (Lolium multiflorum) for primiparous cows 120 days in lactation. Herbage dry matter content, grazing time and daily herbage dry matter intake increased when the time of grazing of the winter pasture was delayed (140 vs 171 g/kg dry matter (DM), 71 vs 110 minutes and 2.7 vs 4.8 kg DM/cow/d respectively; P <0.05) while the increment in the water-soluble carbohydrates content of the herbage was not significantly different between treatments (53 vs 75 g/kg DM; P = 0.09). As a consequence of the higher daily herbage dry matter intake of cows grazing winter pasture late in the morning, daily milk and milksolids production was higher than pasture offered early in the morning (29.2 vs 31.0 L/cow and 2.05 vs 2.19 kg/cow respectively; P <0.05).

Developments in the sheep meat industry: Genetic evaluation of meat yield - Jopson NB; Newman S-AN; McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2009)
Sheep Improvement Ltd. has a 'MEAT' Goal Trait Group which is used to select animals on their genetic merit for meat production. Breeding values are calculated for weight of carcass lean, carcass fat and carcass weight. These breeding values are estimated from live weight and ultrasonic eye muscle dimension data, with the option of incorporating computed tomography (CT) measurements. This served the sheep industry well while carcasses were graded on the basis of carcass weight and GR tissue depth. However, deregulation in the meat industry has seen individual meat processors developing carcass grading systems which not only improve estimates of lean and fat, but also estimate retail yield within individual cuts. SIL have developed a 'MEAT YIELD' module in response to these changes which estimates breeding values for lean weight in the shoulder, loin and hindleg primal cuts. Meat yield data collected from surplus slaughtered progeny are added to live weight and ultrasonic eye muscle data to predict the breeding values. Slaughter progeny should be randomly selected to avoid biasing the meat yield data. This module is likely to be developed further as additional grading systems are implemented, and equations to translate data into standardised measurements will be required.

Differential passage of rumen bacterial populations to the abomasum in sheep : Brief Communication - Laporte-Uribe J; Gibbs SJ (Proceedings of the New Zealand Society of Animal Production, 2009)
Ruminant microflora and fauna enable the degradation of otherwise poorly digestible feeds and are a principal source of metabolisable protein (Faichney, 1996). Rumen outflow, which is dependent on many factors including the physical characteristics of the diet and the level of feed intake, carries both nutrients and microorganisms to the abomasum. The proportional contribution of the various sub-populations of microorganisms to the total pool of abomasal protein is still poorly defined (Dewhurst et al., 2000). It is therefore possible that differences in motility or microhabitat between subpopulations may generate differential retention of certain groups.

DNA methylation events associated with the suppression of milk protein gene expression during involution of the bovine mammary gland : Brief Communication - Singh K; Swanson K; Couldrey C; Seyfert H-M; Stelwagen K (Proceedings of the New Zealand Society of Animal Production, 2009)
During lactation, prolactin activates STAT5 (Signal Transducer and Activator of Transcription), which binds to conserved DNA sequence motifs in promoters of milk protein genes to stimulate their expression (Liu et al., 1997). At drying-off, mammary involution is characterised by a rapid decrease in milk protein gene expression (Goodman & Schanbacher, 1991), including ?S1-casein (Singh et al., 2008). The ?S1-casein promoter features... Continued

Do objective measurements or subjective assessments explain more of the variation in strong wool auction prices? - Sumner RMW (Proceedings of the New Zealand Society of Animal Production, 2009)
Auction prices of a total of 74,134 lots of wool in the strong wool segment of the New Zealand wool clip sold between 1 July 2005 and 30 June 2007, were analysed by multiple regression analysis to estimate the proportion of variation in wool price explained by four objectively measured characteristics and by subjective assessments of length and colour with up to five additional codes. The objective characteristics were vegetable matter content, mean fibre diameter CIE Y (brightness), and CIE Y-Z (yellowness). Changes in the New Zealand dollar exchange rate were adjusted for by covariance against the exchange rate of the US dollar on the day of the auction. The residual standard deviation for the objectively measured characteristics was 22.2 c/kg clean, explaining 80.2% of the variation in price. In contrast, the residual standard deviation for the subjectively assessed codes identifying "outlier" lots in terms of characteristics deemed to be important by scourers and processors was 21.4 c/kg clean, explaining 81.6% of the variation in the auction price. It will thus benefit wool growers to prepare their wool such that lots conform to the recommended best practice guidelines rather than for them to conform solely to objective specifications.

The effect of concentrate supplementation on milk production during an extended lactation in grazing dairy cows : Brief Communication - Phyn CVC; Kay JK; Roach CG; Kolver ES (Proceedings of the New Zealand Society of Animal Production, 2009)
Extended lactation systems where cows are milked for longer than 300 days, provide an opportunity for farmers to use the lactation potential of genetically superior cows, reduce calving and mating costs, even-out labour requirements, and/or build herd size by retaining non-pregnant cows. However, depending upon cow genetic strain and nutrition, milk production can be reduced in an extended lactation system relative to a 'normal' lactation of 260 to 300 days (Kolver et al., 2007; Grainger et al., 2009). Winter-feeding levels are potentially important... Continued

The effect of fasting on live weight in hogget wethers and pregnant mature ewes : Brief Communication - Burnham DL; Morel PCH; Kenyon PR; Morris ST; Stafford KJ (Proceedings of the New Zealand Society of Animal Production, 2009)
Withholding of food and water, or fasting, of sheep for up to 24 hours is a practice commonly employed in the agricultural industry and research sectors. Farmers routinely fast sheep before shearing, pregnancy scanning and transport. Further, with relatively large numbers of animals involved in some experiments, duration of weighing and manipulation time can vary, which may interfere with a comparison of live weight measurements. The determination of the rate of liveweight loss will allow live weights to be corrected to... Continued

The effect of feed restriction during peak lactation on milk production parameters : Brief Communication - Kay JK; Phyn CVC; Williams YJ; Roche JR; Burke CR; Meier S (Proceedings of the New Zealand Society of Animal Production, 2009)
Adverse weather conditions that reduce pasture growth and/or quality can place the lactating dairy cow under periods of transitory nutritional stress. Previous research that has focused on the effects of feed restrictions in a pasture-based dairy system have imposed feed deficits either pre-calving (Roche, 2007), immediately post-calving for five to six weeks (Bryant & Trigg, 1979; Roche, 2007) or up to a 23% restriction in dry matter intake (DMI) (Bryant & Trigg, 1979). All experiments reported an immediate reduction in milk production; however, the longer-term effects varied depending on... Continued

Effect of management change on methane output within a sheep flock - Cruickshank GJ; Thomson BC; Muir PD (Proceedings of the New Zealand Society of Animal Production, 2009)
The introduction of an emissions trading scheme means farmers are likely to incur some form of carbon tax on methane emissions. Consequently, it is important to explore management options that could reduce methane output per unit of product sold. A computer model was developed to test a range of management strategies on methane production, relative to farm output. These included changing ewe live weight, conception rate, scanning percentage, ewe and lamb survival, ewe culling rates, lamb growth rate, hogget lambing and ewe culling age. The dataset used to develop the model contains 6,000 ewe and 8,100 lamb records collected over 8 years. The reference flock used in the model comprised 1,000 ewes plus replacements, 1,378 lambs scanned, 989 lambs sold and 288 replacements kept. The carbon cost was 15.99 kg of methane per lamb sold. Three of the most significant influences on methane production per lamb sold were increasing ewe cull age from 5 to 6 years (4.6% reduction), increasing ewe scanning percentage from 160% to 180% (7.8% reduction) and hogget lambing (11.7% reduction). Effects were not completely additive. The model allows methane output to be estimated for any defined production system and quantifies the most effective management changes to minimise methane production on an individual farm or across the wider industry.

Effect of sex on colour and pH of chilled lamb loins : Brief Communication - Bain WE; McLean NJ; Young EA; PL Johnson (Proceedings of the New Zealand Society of Animal Production, 2009)
With more chilled lamb being exported from New Zealand, there is interest in factors affecting the quality of the chilled product. Two key factors are ultimate pH and the redness of the meat when on display for sale. The possible effect of the sex of the lamb on these quality traits is of interest to the industry (Meat and Wool New Zealand, 2006). A number of studies have reported non-significant differences between ewe and ram lambs at moderate carcass weights of approximately 18 kg, for pH and colour measured within 24 hours post-slaughter... Continued

Effect of water soluble carbohydrate concentration of ryegrass on the partial preference of sheep for clover - Allsop ARC; Nicol AM; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2009)
A trial was carried out to determine whether grass cultivar or water soluble carbohydrate (WSC) concentration would influence the partial preference of sheep for clover and ryegrass. Six mixed age Coopworth ewes were housed in individual pens and once a day offered swardlet monocultures of white clover adjacent to one of three perennial ryegrass cultivars. One swardlet of each grass cultivar was shaded and the other left un-shaded in order to create differences in WSC concentration. WSC concentration did not differ among ryegrass cultivars but was lower in shaded (210 g/kg dry matter (DM)) than non-shaded (230 g/kg DM) ryegrasses. Neutral detergent fibre was significantly higher in the un-shaded (439 g/kg DM) than non-shaded (422 g/kg DM) ryegrass (P <0.01). The total number of bites from clover swardlets fed adjacent to shaded grass swardlets was 21% greater (P = 0.026) than when fed adjacent to non-shaded grass swardlets. Sheep took a significantly lower proportion of bites from clover when paired with un-shaded (44%) than shaded (55%) ryegrass (P = 0.03). There were no significant effects of ryegrass cultivar on any aspect of the preference tests. The results of this work support the hypothesis that partial preference for clover can be manipulated by altering the WSC concentration of companion ryegrass by shading but not, in this case, by ryegrass cultivar.

The effect of weaning at 10 or 14 weeks of age on liveweight changes in the hogget and her lambs : Brief Communication - Mulvaney FJ; Morris ST; Kenyon PR; West DM; Morel PCH (Proceedings of the New Zealand Society of Animal Production, 2009)
Kenyon et al. (2004) revealed via a survey, that a major reason why New Zealand farmers do not breed ewe hoggets (7-9 months old) is perceived detrimental effects on two-tooth breeding live weight, resulting in reduced two-tooth reproductive performance. Kenyon et al. (2008) confirmed this by showing hoggets that lambed had reduced two-tooth live weight and condition score at breeding. A potential means of minimising any potential negative effects on... Continued

Effects of birth weight on survival in twin born lambs - Morel PCH; Morris ST; Kenyon PR (Proceedings of the New Zealand Society of Animal Production, 2009)
Lamb survival to weaning decreases as litter size increases (single > twin > triplet > quads), with birth weight being a major factor affecting survival. The purpose of the present study was to investigate the effects of birth weight (BWT) and related traits on survival in twin born lambs. Data from a total of 3,834 twin lambs born to mixed aged ewes were analysed. For statistical analysis the lambs were allocated according to birth weight (BWT) within litter to three groups (Light = Lightest lambs within pairs, Equal = Lambs of similar weight within pairs and Heavy = Heaviest lambs within pairs). The survival rates differed (P <0.05) between Light, Equal and Heavy (80%, 89% and 83%, respectively). BWT was positively related (P <0.001) to survival in the Light group, but not in the other two groups. The smaller the difference in BWT between siblings, the higher the likelihood of the Light lambs surviving. Therefore, reducing the difference in BWT within a set of twins will have the potential to increase overall lamb survival.

Effects of high potassium on in vitro fermentation pattern and C18 fatty acid metabolism of pasture grass - Sun XQ; Dewhurst RJ.Gibbs SJ (Proceedings of the New Zealand Society of Animal Production, 2009)
The effect of high potassium concentration on rumen fermentation and fatty acid biohydrogenation (BH) were investigated in a 6 hour in vitroincubation. A pasture grass sample with 26.3 g/kg dry matter (DM) of potassium was used as control. Supplemental levels of 10, 20 and 30 g/kg DM of potassium were added as potassium chloride. Results showed that high potassium concentration had no significant effects (P >0.05) on pH, molar concentrations of total or individual volatile fatty acids (VFA), concentrations of C18:0, C18:1 trans 11, C18:1 cis 9, C18:2n-6, or BH of C18:2n-6after incubation. However, concentration and BH of C18:3 n-3were significantly (P <0.01) affected by potassium supplementation. Both the 20 and 30 g/kg DM supplementation significantly (P <0.05 and P <0.01, respectively) decreased the concentration but increased BH of C18:3n-3. This preliminary study indicates that high concentrations ofpotassium alter rumen fatty acid metabolism. Further studies are needed to confirm this and investigate the possible causal mechanisms.

Effects of sub-clinical endometritis on ovarian follicular activity in postpartum dairy cows - Back PJ; Ledgard AM; Beaumont S; Berg MC; Peterson AJ; McNatty KP; Green MP (Proceedings of the New Zealand Society of Animal Production, 2009)
The effects of sub-clinical endometritis (scEndo) on ovarian follicular activity in pasture-fed dairy cows were determined. The uterine-health status of lactating dairy cows (n = 169) was assessed on day (D) 21 (± 3 days) postpartum by Metricheck. In a sub-population (n = 47; 32 clean, 15 scEndo), Metricheck assessment was repeated on D42 and uterine cytology undertaken on D21 and D42 [scEndo = polymorphicnuclear (PMN) cells >18%]. Follicular activity was assessed by ultrasound on D42 and D63. Metricheck evaluation revealed that the proportion of cows with scEndo was 15/169 (8.9%) and 4/47 (8.5%) on D21 and D42 respectively. Irrespective of the method used to determine scEndo, dominant (P <0.001) but not subordinate (P >0.1) follicles were larger and grew faster on D63 than on D42. Based on the D21 Metricheck but not the %PMN classification, dominant follicles of scEndo cows were larger and grew faster (P = 0.02) than those in clean cows. No overall effect of uterine status was found on the subordinate follicles, although these tended (P = 0.06) to be larger on D63 than on D42 but only in clean cows. Thus early postpartum scEndo appears to modulate the subsequent size of the dominant follicle. However, it remains to be determined whether this affects the subsequent fertility of these cows.

Exploring the relationships between plant chemical composition and nitrogen partitioning in lactating dairy cows fed ryegrass-based diets - Vibart RE; Koolaard J; Barrett BA; Pacheco D (Proceedings of the New Zealand Society of Animal Production, 2009)
Data from experiments in which cows consumed ryegrass-based diets were used to evaluate the effects of plant constituent concentrations and nutrient ratios on the partitioning of nitrogen (N) secreted into milk and excreted as waste products (urine + faeces). The data set used from 32 publications with 170 treatment means, was derived from studies where freshly-cut or grazed pasture comprised more than 70 % of the total diet on a dry matter basis. The objectives were to identify suitable predictors of N partitioning, both across and within studies, and to examine the relative weight these predictors have on the partitioning of dietary N. Total excretion of N (g/d) and urinary N (g/d) were best predicted by the single predictor crude protein concentration, but better relationships were obtained by adding water soluble carbohydrate (WSC) and neutral detergent fibre concentrations to the models. Although significant across studies, no single plant constituent variable was selected using the meta-analytical approach. The most reliable predictions of N in waste products and urine required measures of N intake for urinary N excretion, or in combination with total OM intake for total N excretion.

Factors associated with frequency of lameness in dairy cattle managed in pasture based systems with the addition of supplementary feeds : Brief Communication - Diaz-Lira CM; Margerison JK; Lopez-Villalobos N; Gibbs SJ (Proceedings of the New Zealand Society of Animal Production, 2009)
Lameness is one of the main welfare problems of New Zealand dairy herds (Chesterton et al., 2008) and contributes directly to cow culling, treatment costs, production losses and reduced economic efficiency (Kossaibati & Esslemont, 1997). The incidence of lameness can be high, affecting as many as 60% (Vermunt, 2004) of cows annually, but can vary from between 5 and 55% (Clarkson et al., 1996) according to differing observation techniques and... Continued

Feeding birdsfoot trefoil (Lotus corniculatus) reduces the environmental impacts of dairy farming - Woodward SL; Waghorn GC; Watkins KA; Bryant MA (Proceedings of the New Zealand Society of Animal Production, 2009)
An indoor feeding experiment using 16 late lactation Friesian dairy cows measured effects of increased proportions of birdsfoot trefoil (Lotus corniculatus; Lotus) in the diet on the partitioning of nitrogen (N) between milk, faeces and urine. Cows were housed in metabolism stalls for 12 days and fed diets containing 0%, 15%, 29% or 45% Lotus (% Lotus dry matter (DM) per DM intake (DMI)) with the remainder perennial ryegrass pasture. Increasing the proportion of Lotus in the diet did not affect DMI but increased milk (P <0.001) and milksolids yields (P <0.01). The percentage of N intake partitioned to milk increased from 16% (0% Lotus) to 21% (45% Lotus) (P <0.01) with an increasing proportion of Lotus in the diet. The percentage of N intake excreted as faecal N also increased from 29% (0% Lotus) to 38% (45% Lotus) (P <0.001) while the percentage excreted as urinary N was reduced from 49% (0% Lotus) to 34% (45% Lotus) (P <0.01). Partitioning of N towards faeces has a favourable environmental impact since faecal N is largely retained in soils whereas urinary N is subject to volatilisation as ammonia, losses as nitrous oxides (a greenhouse gas) and leaching into groundwater.

Genetic and phenotypic parameter estimates for growth, yield and meat quality traits in lamb - Payne GM; Campbell AW; Jopson NB; McEwan JC; Logan CM; Muir PD (Proceedings of the New Zealand Society of Animal Production, 2009)
The Meat and Wool New Zealand Central Progeny Test has evaluated 143 sires from terminal and dual purpose breeds for meat yield and growth. Meat quality traits, including pH, fat and meat colour (CIE L*, CIE a*, CIE b*) have also been measured. This paper determines genetic variation in these quality traits and their correlations with growth and meat yield. Progeny were drafted for slaughter at a threshold live weight of 34 kg at weaning and 36 kg for subsequent slaughters. Fat colour, eye muscle meat colour and meat pH were measured 24 hours post-slaughter, with meat colour measured after a 30 minute bloom. Heritabilities and genetic correlations between traits were calculated from the measurements. Data were analysed with a linear mixed model in ASReml. Results showed significant variation among sires for meat quality. Heritabilities were moderate for most meat quality traits: fat colour (CIE b* 0.42), initial meat colour (CIE L* 0.29, CIE a* 0.19) and pH (0.12). Relationships between meat quality and yield/growth showed that meat CIE L* had a positive genetic correlation with weaning weight (0.42). Simulated index selection for growth rate and meat yield predicted a small increase in meat lightness and decline in fat yellowness (0.231 and -0.227 units per generation and unit selection intensity, respectively).

Genetic parameters for colour stability of chilled lamb : Brief Communication - McLean NJ; PL Johnson; Bain WE; Greer GJ; Dodds KG (Proceedings of the New Zealand Society of Animal Production, 2009)
An increasing proportion of New Zealand lamb meat is shipped to the European Union market as chilled rather than frozen product, with 29% exported as chilled product in 2005/06 (Meat and Wool New Zealand, 2006). New Zealand's lamb export markets are located such that the chilled product travels large geographical distances via freighted shipping, taking six to twelve weeks to reach the destination. Once chilled lambs arrives at its destination it is further processed and packaged to specification for retail sale. Shelf life and colour stability are particularly important for this... Continued

Genetic parameters for primal cut meat yield traits in sheep - Jopson NB; McEwan JC; Logan CM; Muir PD (Proceedings of the New Zealand Society of Animal Production, 2009)
Lamb carcass grading is changing from classification on carcass weight and tissue depth (GR) to yield grading systems such as VIAscan®. Under the VIAscan® system, farmers receive information on the percentage lean meat yield from the hindleg, loin and shoulder primal cuts, and payments are based on these measurements. Genetic improvement programmes for meat have concentrated on producing age-adjusted breeding values for carcass lean and fat weight from live weight and ultrasonic eye muscle measurements. This has worked well for grading using carcass weight and GR, but does not quantify differences in yield between meat cuts. Carcass and VIAscan® yield data collected for the Meat and Wool New Zealand Central Progeny Test were analysed to determine heritabilities and genetic and phenotypic correlations for meat yield traits. The dataset contained around 6,600 progeny from 143 terminal sire or dual purpose rams. Data were analysed using linear mixed models in ASReml. The results showed significant variation between sires for lean yield traits. Heritabilities for age-adjusted lean weight in the hindleg, loin and shoulder were 0.40, 0.37 and 0.42, respectively. Genetic correlations for age-adjusted weight of lean by carcass region were all high (range 0.94 to 0.96), but were lower (0.62 to 0.85) when adjusted to constant carcass weight.

Genetic parameters for somatic cell score in dairy goats estimated by random regression - Apodaca-Sarabia CA; Lopez-Villalobos N; Blair HT; Prosser CG (Proceedings of the New Zealand Society of Animal Production, 2009)
The objective of the study was to estimate genetic parameters of somatic cell score (SCS = log2 of somatic cell count / 1000) in New Zealand mixed-breed dairy goats using a random regression model. The dataset comprised 37,051 herd-test records of somatic cell counts (SCC) from 3,688 does kidding between 2000 and 2007 distributed in 47 herds. The mixed model included the fixed effects of contemporary group (herd-year-month of kidding), lactation number (1st, 2nd and 3rd), and the covariables day-of-month, proportion of Saanen, Nubian, Alpine and Toggenburg breeds, heterosis, and a second-order orthogonal polynomial of days in milk across all data and for each lactation number. The random effects included a second order random regression polynomial for the additive animal effect and the doe permanent environmental effect within parity and doe permanent environmental effect across parities. The residual variance was assumed heterogeneous, with different residual variances for each of the nine months of lactation. Estimates of heritability increased from 0.12 to 0.25 from the beginning to the end of the lactation and estimates of repeatability ranged from 0.46 to 0.59, also increasing from the beginning to the end of lactation. These results show that genetic improvement can be achieved in SCC by including SCS in selection index.

Identification of potential impacts of New Zealand dairy housing systems on dairy cow welfare : Brief Communication - Arnold NA; Verkerk GA; Gregory R; Matthews LR (Proceedings of the New Zealand Society of Animal Production, 2009)
Although housing of dairy cows is not acommon management practice in New Zealand, it is becoming increasingly used for a variety of reasons. Potential benefits from dairy housing have been identified as pasture protection, effluent management, cow health and welfare, supplementary feed management and increased production (Dexcel, 2005). Laven and Holmes (2008) further explored potential health and welfare issues associated with increased use of housing for dairy cows in New Zealand. However, there is to date very little empirical research... Continued

Investigating marbling and its relationship to meat quality in New Zealand pasture fed lamb - Young EA; Bain WE; McLean NJ; Campbell AW; PL Johnson (Proceedings of the New Zealand Society of Animal Production, 2009)
This is the first report of marbling in New Zealand pasture finished lamb. Marbling and meat quality data were collected on 1,056 loins from pasture finished lambs. Marbling was subjectively assessed on loin cut surfaces, using a five point visual scale (1 = Low, 5 = High), and objectively assessed using computer tomography (CT) scanning. Tenderness was objectively measured on loins that had been frozen. Corresponding loins from the lambs with the fifty highest (High) and fifty lowest (Low) subjective marbling scores were taste panelled after chilled storage. The average subjective scores were 2.94 and 0.94 for the High and Low groups respectively, with the objectively measured CT fat percentages 8.0% and 10.0% respectively, both significant differences (P <0.001). Loins from the High group were significantly (P <0.01) more tender than loins from the Low group as assessed objectively, however, this difference was not detected by the taste panel when assessing texture. The taste panel did not detect any significant differences in juiciness, flavour or odour between the two groups. Our findings suggest that this level of marbling in pasture fed, New Zealand chilled stored lamb is insufficient to influence meat quality as assessed by a taste panel.

Lancorp Farming Lecture: 'Clean, green and ethical' animal reproduction: extension to sheep and dairy systems in New Zealand - Martin GB; Durmic Z; Kenyon PR; Vercoe PE (Proceedings of the New Zealand Society of Animal Production, 2009)
In this paper, we present our approach for 'clean, green and ethical' (CGE) management in small ruminants and dairy cattle, in a context that is relevant to New Zealand livestock industries. We will focus in particular on reproduction and nutrition aspects, with several possibilities for CGE management: 1) control of the timing of reproductive events by using socio-sexual signals (the 'male effect') to induce synchronised ovulation in females; 2) 'focus feeding' - short periods of nutritional supplementation that are precisely timed and specifically designed for each event in the reproductive process; 3) 'nutritional pharmacology' - a term that reflects the possibility of using forages containing 'bioactive' compounds to improve rumen health and efficiency with environmental benefits through the reduction of methane emissions from ruminants; 4) maximizing offspring survival by a combination of management and nutrition; 5) genetic selection for fertility, fecundity and temperament. These tools involve novel ways of manipulating the endogenous control systems and production of animals. Ultimately, the CGE tools can be cost-effective, increase productivity and, at the same time, greatly improve the image of meat and milk industries in society and the marketplace.

Management of weanlings on commercial Thoroughbred stud farms in the North Island of New Zealand - Stowers NL; Rogers CW; Hoskin SO (Proceedings of the New Zealand Society of Animal Production, 2009)
The feeding of concentrates to growing thoroughbred horses in New Zealand is common practice, despite the availability of pasture all year round. Whilst the sale of young stock is the primary focus of the majority of the breeders in the Thoroughbred industry, there is still limited data on the production process and the optimal strategy to grow horses to their maximum athletic potential. To obtain data on the management of Thoroughbred weanlings a face-to-face survey was conducted on 46 stud farms in the northern and central regions of the North Island during the 2007/08 breeding season. Analysis was based on location and size of the breeding operation. Prior to weaning, 87% of foals were exposed to concentrate feed and all weanlings received concentrates. Weanlings received 47 ± 2 MJ of digestible energy (DE) and 563 ± 40 g of crude protein (CP) per day from concentrate initially. This increased to 64 ± 6 MJ DE and 683 ± 54 g CP immediately before yearling preparation. The data collected indicated that management of weanlings is generally consistent between regions and across farm sizes with weanlings receiving large quantities of concentrate feed whilst at pasture.

Maternal environment as a regulator of birth weight and body dimensions of newborn lambs - Sharma RK; Jenkinson CMC; Blair HT; Kenyon PR; Parkinson TJ (Proceedings of the New Zealand Society of Animal Production, 2009)
The present research study was undertaken to investigate the effect of maternal uterine environment on birth weight of lambs. Embryos were transferred within, and reciprocally between, Suffolk and Cheviot sheep to establish four groups of pregnancies: Suffolk in Suffolk (SinS; Large control), Suffolk in Cheviot (SinC; Restricted uterine environment) Cheviot in Suffolk (CinS; Luxurious uterine environment) and Cheviot in Cheviot (CinC; Small control). Birth weight and other morphological characteristics of lambs such as head width, head length, crown-rump length, heart girth, fore leg length, hind leg length and femur length were recorded within 24 h of birth. Various placental parameters were also recorded at lambing. Birth weight of SinC lambs (5.04 ± 0.20 kg) was significantly (P <0.05) lower than SinS lambs (5.93 ± 0.19 kg). All of the body dimensions were also significantly (P <0.05) reduced in SinC compared with SinS lambs. However, neither birth weight nor other morphological parameters were significantly different (P >0.05) between CinC and CinS lambs. Among placental parameters, cotyledon number was significantly (P <0.05) lower in CinS (57.48 ± 6.27) than SinS group (74.17 ± 5.88). These results indicate that a restricted maternal uterine environment affects birth weight probably via alteration to placental characteristics.

A new generation meat program in Australia within the Co-operative Research Centre for Sheep Industry Innovation - Pethick DW; Jacob RH; McDonagh MB; O'Halloran WJ; Ball AJ; Hopkins DL (Proceedings of the New Zealand Society of Animal Production, 2009)
The Information Nucleus flock (INF) is the central focus of the Co-operative Research Centre (CRC) for Sheep Industry Innovation. It is made up of eight sheep flocks across Australia that are genetically linked by the use of common sires. The objective of the INF is to measure a range of biological and production parameters and to produce heritability estimates and genetic correlations for a range of new traits. Approximately 100 sires are mated annually by artificial insemination to 5,000 ewes across the sites. Sires from various breeds are joined to Merino and crossbred ewes. Each year 2,000 progeny are evaluated for a wide range of meat production and consumer-relevant traits. Some of these traits are new and novel, such as the content of iron, zinc and omega-3 fatty acids. Their measurement is designed to ensure lamb maintains its marketing edge as a healthy, nutritious meat so that it is the consumer's preferred choice of meat. This paper will provide an overview of the program and highlight specific areas that are novel with respect to sheep meat.

An option for managing triplet bearing ewes on extensive properties - Thomson BC; Muir PD (Proceedings of the New Zealand Society of Animal Production, 2009)
Heavier ewe live weights and the trend toward composite genetics has resulted in an increasing proportion of triplet bearing ewes within a flock. On some extensive properties, triplet lambs have much lower survival rates. This work examined the effect on lamb survival and the profitability of shifting scanned triplet ewes to an intensive property for lambing. Scanned triplet bearing ewes on a large extensive property were allocated to two groups; Intensive (150 ewes) and Extensive (770 ewes). Intensive ewes were transported to a smaller downland property prior to lambing and the Extensive ewes remained on the farm and were managed normally. Weaning percentages were higher under intensive management (222% lambs weaned/ewe present at weaning) than under extensive management (171%). The intensive property also had higher lamb weaning weights per ewe (58.2 vs 47.2 kg lamb weaned/ewe scanned). Differences in survival between the properties suggest there is a significant potential to reduce death rate in triplet lambs. Returns on feed consumed were modelled using Farmax® and were 21.1 and 17.1 c/kg dry matter consumed over the trial period on the respective properties. In addition, removal of the triplet bearing ewes from the extensive property freed up resources which could be used to improve the performance of other stock.

Parasite-related traits in lambs sired by resistant or resilient Romney sires : Brief Communication - Wheeler M; Morris CA; Devantier BP (Proceedings of the New Zealand Society of Animal Production, 2009)
Finding methods of dealing with increasing levels of anthelmintic resistance is important to the New Zealand sheep industry. Genetic selection within the sheep population for animals that are less reliant on anthelmintic therapy is one approach, and AgResearch has bred selected lines of Romneys over recent decades. These have included lines for resistance and for resilience (Bisset et al., 2001). The resistant line, selected for low faecal egg count (FEC) in lambs, was established in 1979. The line selected for increased resilience in lambs was set up in 1994. Resilience is the ability of animals to maintain acceptable health and growth under high parasite challenge, with minimal need for anthelmintic treatment. We report results here from a study to evaluate sires from these two long-term breeding lines, with progeny measured for weaning weight (WWT) and faecal egg count (FEC) at weaning.

Presidential Address 2008: Where are we going and who’s driving? - Dewhurst RJ (Proceedings of the New Zealand Society of Animal Production, 2009)
I come to the 2008 Presidential Address in the unusual, but not unique, situation of preparing to leave New Zealand and move to a new research leadership position overseas. I hope that this will give me an even better platform from which to make some constructive and objective comments about the direction of our research and livestock industries. I will take the approach recommended by a previous research director of... continued

Prevalence and identification of systemic markers of sub-clinical endometritis in postpartum dairy cows - Green MP; Ledgard AM; Berg MC; Peterson AJ; Back PJ (Proceedings of the New Zealand Society of Animal Production, 2009)
The prevalence of sub-clinical endometritis (scEndo) and identification of serum markers of scEndo was investigated in pasture-fed, postpartum dairy cows. Mixed age lactating dairy cows (n = 169) were examined for uterine health status on day (D) 21 postpartum (± 3 days) by Metricheck classification. On D42 in a subpopulation (n = 47; 32 clean, 15 scEndo) Metricheck assessment was repeated and uterine cytology undertaken on D21 and D42 [scEndo = polymorphicnuclear (PMN) cells >18%]. Uterine bacteriology, as well as haematological, biochemical and milk parameters were also measured. The prevalence of scEndo was 15/169 (8.9%) and 4/47 (8.5%) cows on D21 and D42 respectively. A high incidence of self-resolving scEndo (11/15, 73%) was revealed. Numerous species of pathogenic bacteria were isolated from both scEndo and clean cows. Despite the uterine infection being sub-clinical, systemic markers were detectable as on D21 and D42 haematological and biochemical parameters differed. Irrespective of the scEndo classification method used, the mean blood neutrophil concentration was higher (P <0.05) and plasma albumin lower (<0.05) in scEndo cows compared to clean cows. Milk fat and protein % also differed (P <0.05) between scEndo and clean cows. The monitoring in early lactation of these markers could aid identification of scEndo, thereby preventing potentially detrimental effects on subsequent fertility.

Quality of chilled-never-frozen versus chilled-frozen-thawed lamb : Brief Communication - Wiklund E; Farouk MM; Stuart A; Cartwright S; Penney N; Rosenvold K (Proceedings of the New Zealand Society of Animal Production, 2009)
Chilled lamb currently attracts a premium price over frozen accelerated conditioning and ageing (AC&A) lamb in New Zealand's traditional lamb markets. AC&A lamb is fully frozen within 48 h of slaughter (Hagyard, 1979). The price differential between chilled-never-frozen (CNF) and AC&A frozen lamb is due to CNF lamb having more reliable tenderness, less drip loss and longer colour display life than AC&A lamb. There is no clear evidence that the eating quality of CNF lamb is superior to... Continued

Rates of genetic progress being achieved throughout the New Zealand ram breeding industry - Amer PR (Proceedings of the New Zealand Society of Animal Production, 2009)
Changes in the rate of genetic progress in the New Zealand sheep industry since 1990 are linked to structural aspects of breeding scheme design and to major industry sheep breeding initiatives. Data was sourced from the December 2007 SIL-ACE genetic evaluation for 140 recorded Dual Purpose flocks and 62 recorded Terminal Sire flocks. Genetic trends in both of these flock types approximately doubled after the introduction of Sheep Improvement Ltd. and there was a further incremental increase of similar magnitude after the introduction of the Central Progeny Test and SIL ACE. Substantial variation in the magnitude of genetic trends was observed across flocks within and between breeds. Large numbers of flocks average less than 50 cents gain in index per year, while significant numbers of flocks are achieving in excess of 150 cents gain per year. Flocks with higher rates of genetic gain tended to be using superior rams introduced from other flocks, while flocks with lower rates of genetic gain tended to be repeatedly using older sires of lower genetic merit. The implications of these results for industry sheep genetic improvement initiatives are discussed.

Real time in situ measurement of rumen methane concentration in the rumen of cattle : Brief Communication - Laporte-Uribe J; Gibbs SJ (Proceedings of the New Zealand Society of Animal Production, 2009)
Methane dominates agricultural greenhouse gas emissions in New Zealand (Leslie et al., 2008). Research efforts in New Zealand to date have been directed toward prediction of emissions, most often using the rumen gas marker sulphur hexafluoride (SF6) (Lassey et al., 1997) to predict methane emissions in grazing livestock. However, the errors associated with this method necessitate the use of multiple day sampling programmes and large numbers of individuals to overcome... Continued

Realities of clip preparation for strong wool from adult sheep - McDermott AK; Sumner RMW (Proceedings of the New Zealand Society of Animal Production, 2009)
There has been debate about the usefulness and profitability of varying standards of clip preparation, and the timing and frequency of shearing. This paper takes a modelling approach to gauge the relative economic value of adjusting these factors to modify the style of wool. Although adult fleeces were used as the basis for the analyses presented, the model can be used to handle all types of wool. The model shows that shearing in spring, when wool colour is best, increases wool revenue. There may however, be conflict with the overall management of the ewe flock. Similarly, shearing twice a year will yield higher wool revenue, but provides a lower net margin from wool because of higher shearing costs, but with possible management benefits. Skirting levels can have a greater impact on wool revenue of twice-yearly shorn fleece wool as second shorn oddments are primarily downgraded on length with little change in yellowness. If the grower is supplying to a specified contract, the price differential associated with clip preparation may be substantively greater than those apparent in the auction.

Relationship between blood phylloerythrin concentration and gamma-glutamyltransferase activity in facial eczema-affected cattle and sheep - Morris CA; Hickey SM; Phua SH (Proceedings of the New Zealand Society of Animal Production, 2009)
Phylloerythrin (PLE) is a photo-dynamic compound, a natural breakdown product of chlorophyll. Its concentration and relationship with gamma-glutamyltransferase (GGT) were determined in animals seriously affected with facial eczema (FE). Seven commercial cattle herds (n = 1,455) and one experimental sheep flock (n = 597), each containing clinically affected animals, were monitored. On a pooled within-farm basis, mean PLE concentration was significantly higher in clinical FE cases than in non-clinical animals in cattle (28.7 vs 16.0 relative units, P <0.001), and in lambs (0.282 vs 0.024 µg/ml, respectively, P <0.001). PLE concentration rose in some, but not all, animals when GGT activity exceeded ˜600 IU/L in cattle and ˜400 IU/L in lambs (Reference GGT range in normal (unchallenged) animals: 0 to 40 IU/L, cattle; 32 to 70 IU/L, sheep). A heritability for PLE concentration was estimated in cattle (0.19 ± 0.07), and phenotypic and genetic correlations with LogeGGT were 0.37 ± 0.02 and 0.92 ± 0.09, respectively. In the lambs the phenotypic correlation between LogeGGT and PLE was 0.32 ± 0.04. Thus PLE is a partially inherited trait, and is associated with visible signs of FE, especially above GGT thresholds of ˜600 IU/L in cattle and ˜400 IU/L in lambs.

Responses to selection for pubertal traits in Angus cattle over 23 years - Amyes NC; Morris CA (Proceedings of the New Zealand Society of Animal Production, 2009)
Selection to change age at puberty over 23 years was monitored in Angus cattle in a Ruakura study. A foundation herd was divided in 1984 into four lines: a control unselected line, and lines selected for high age-at-puberty (Age+), low age-at-puberty (Age-), and high scrotal circumference (SC), with the last two lines being merged later. Age at puberty (first oestrus, AFO) was determined in heifers from observations of first behavioural oestrus date; puberty was determined in bulls from SC records from 8 to 13 months of age. Selection for AFO was applied mainly to bulls, using the genetic correlation between AFO and SC from our data (-0.25 ± 0.09). Puberty records from 6,473 weaned calves were analysed, using restricted maximum likelihood methods to determine genetic changes achieved by line. Realised heritability estimates were 0.26 ± 0.03 (standardised AFO), and 0.40 ± 0.04 (individual SC records; repeatability over ages, 0.68 ± 0.01). Averaging over recent year's data, Age- line heifers had lower AFO than Age+ line heifers by 69 days (19%; 1.33 phenotypic standard deviations), and bulls had larger SC by 3.0 cm (9.9%; 1.17 phenotypic standard deviations). Correlated responses in pregnancy rate favoured Age- over Age+ females at all ages.

Retrospective examination of the breeding efficiency of the New Zealand Thoroughbred and Standardbred - Rogers CW; Gee EK; Vermeij E (Proceedings of the New Zealand Society of Animal Production, 2009)
To describe the industry structure and breeding efficiency of the Thoroughbred and Standardbred populations in New Zealand retrospective reproductive data for the 1989/90 to 2004/05 breeding seasons were obtained from online industry databases and collated for analysis. Data were examined using descriptive statistics, and Kaplan-Meier survival analysis. From 1989/90 to 2004/05 breeding season there was a 36% and 37% reduction in the national broodmare herd and 45% and 40% reduction in foal crop for the Standardbred and Thoroughbred populations, respectively. During this period the number of sires decreased but there was an associated increase in the mean number of mares served by a sire. The mean end of season fertility was 77.9 ± 0.3 % for Thoroughbreds and 86 ± 0.2 % for Standardbreds. The commercial life of a stallion was estimated to be 3 and 4 years for Thoroughbred and Standardbred sires, respectively. Shuttle sires were younger, and covered larger books of younger mares than other sire categories. Expensive and shuttle sires cover larger books of younger mares and therefore may have an advantage compared to low or medium priced sires in producing larger numbers of potentially successful progeny.

Seasonal variation in venison drip loss and tenderness : Brief Communication - Wiklund E; Stuart A; Dobbie PM; Littlejohn RP (Proceedings of the New Zealand Society of Animal Production, 2009)
Venison is a high quality product with several attributes attractive to consumers. It is tender, has low fat content, has a favourable fat composition and has high levels of minerals (Hoffman & Wiklund, 2006). However, New Zealand venison processors have indicated a seasonal variation in the amount of drip. Poor colour stability can also be a problem, sometimes even in vacuum bags when it can occur after extended storage of chilled product. The purpose of this study was to determine seasonal variation in drip loss and tenderness in... Continued

Sheep Improvement Limited (SIL) - the first 10 years: Introductory remarks - Newman S-AN (Proceedings of the New Zealand Society of Animal Production, 2009)
Garrick et al. (1992) defined the six major components of performance recording schemes designed for genetic improvement on a national scale as committed buyers, motivated breeders, database, genetic technology, animal breeding research, and extension. The major factor determining the effectiveness of a national scheme is the way that each of these components is matched to industry needs and... Continued

SIL - progress over a decade - Young MJ; Wakelin R (Proceedings of the New Zealand Society of Animal Production, 2009)
In the 10 years that Sheep Improvement Ltd (SIL) has been operational, the system has continued to develop to meet the needs of breeding flock owners and their ram buying clients. New traits have been added to the evaluation. More flocks are using across-flock evaluations, but there is the opportunity to grow this significantly. The language of SIL is well accepted by industry and offers the most likely path to integration of DNA based genetics into the sheep industry. While a large proportion of rams used by the New Zealand sheep industry come from SIL flocks, a significant section of the industry are still not comfortable with SIL figures when purchasing rams. Greater penetration into the ram buying industry and further into the meat processing industry are challenges for SIL and its collaborators. SIL must maintain and enhance its relevance to industry. This means focused research that addresses key issues and a significant extension effort to increase the proportion of industry that has confidence in using SIL and related technologies.

SIL-ACE - Increasing access to genetic information for sheep farmers - Young MJ; Newman S-AN (Proceedings of the New Zealand Society of Animal Production, 2009)
SIL-ACE is a large-scale, across-flock, across-breed genetic evaluation carried out bi-monthly by SIL. Goal trait groups considered include Growth, Meat (carcass merit), Wool, Reproduction and Resistance to internal parasites. The SIL-ACE dataset comprises over 330 flocks and 3.2 million animals. Leader lists for top-rated 200 sires are published on the www.sil.co.nz website. These comprise the top 5 to 10% of sires for each index or goal trait group considered. Visual depictions of flock connectedness are also provided. Breeders obtaining within flock reports based on the SIL-ACE genetic evaluation, can use a percentile bands table as a scale to judge the merit of animals they are considering for selection. Developments underway will lead to other traits being added to the SIL-ACE evaluation such as lamb survival and ewe performance, resulting in more powerful selection tools to better target genetics suited to a particular users needs.

A simulation model to partition ewe efficiency into component traits for genetic analysis - Sise JA; Shackell GH; Byrne TJ; Glennie SF; Amer PR (Proceedings of the New Zealand Society of Animal Production, 2009)
Ewe efficiency is extremely topical in the New Zealand sheep industry. This paper describes a stochastic simulation model which facilitates partitioning of a defined ewe efficiency equation into its component genetic traits. It accounts for, and simplifies, the complex and sometimes unfavorable interactions among components of ewe efficiency. The model tracks simulated genetic effects, inherited from the ewe's sires, in breeding ewes and their lambs for key performance recorded traits. The traits simulated are weaning weight, mature weight, number of lambs born, lamb survival, and longevity. Ewe efficiency is defined as the difference between value of lambs weaned and ewe and lamb costs, rather than as a ratio. Output value in NZ$ for the efficiency equation is computed on a ewe by ewe basis, as a function of number of lambs born, lamb survival and weight of lamb weaned, with each of these components partly influenced by one or more genetic effects inherited from simulated sires of the breeding ewes. Preliminary results from the model have identified litter size, ewe longevity, maternal lamb survival, and maternal weaning weight as being important drivers of ewe efficiency. The relative balance of their importance is influenced by farm production levels and environment.

Strategically reducing time on pasture: Dairy cow intake, production, welfare, and excretory behaviour - McLeod KLM; Clark CEF; Glassey CB; Gregorini P; Costall DA; Betteridge K; Jago JG (Proceedings of the New Zealand Society of Animal Production, 2009)
In wet spring conditions, cows are often stood off pasture reducing their pasture intake. However, studies indicate that despite reduced grazing access, pasture intake and milk production can be maintained. This study restricted daily grazing access to eight hours in early lactation to determine the effect on pasture intake, milk production, and urination distribution. Forty-eight Holstein-Friesian cows were allocated to three duplicated treatments. Cows had access to pasture for either four hours after each milking (2x4), eight hours between milkings (1x8), or for 24 hours, excluding milking times (Control). When not grazing, the 2x4 and 1x8 treatments were stood off on a bark pad. The 1x8 cows ate less pasture (10.9 kgDM/cow/d; P <0.05) than the Control (13.6 kgDM/cow/d), but the 2x4 intake (13.0 kgDM/cow/d; P = 0.46) was not different to the Control. The 1x8 and 2x4 cows produced less milk (20.2 and 21.5 kg milk/cow/d respectively; P <0.05), relative to the Control (23.3 kg milk/cow/d). Urinations on pasture and races were reduced (P <0.05) from 90% (Control) to 62% (1x8) and 65% (2x4) of total urinations. Eight-hours grazing per day should be offered as two four-hour periods to maintain cow pasture intakes, although milk yields are reduced. Corresponding changes in urination distribution may have environmental benefits.

Trans-Tasman genetic evaluation of sheep - spreading the net wider - Young MJ; Newman S-AN; Apps R; Brown DJ (Proceedings of the New Zealand Society of Animal Production, 2009)
At the instigation of local breed groups, Sheep Improvement Ltd. (SIL) and Sheep Genetics (SG) exchanged flock data and conducted genetic evaluations on the combined dataset. Results from each system show only modest changes in breeding values compared to analyses of their respective within country datasets. Correlations of breeding values (BVs) were 96 to 100% for weaning weight, autumn live weight, ultrasonic muscle, ultrasonic fat, fleece weight and number of lambs born. Correlations between BVs generated by the two systems from the same datasets were less strong but still good at 69 to 89%, for most traits. This was attributed to differences in parameters used by the two analysis systems and to some measurements being taken at different ages. The weakest correlations occurred for ultrasound scan traits at 14 to 65% since SG adjusts these to constant 'carcass' weight but SIL does not. It is concluded that the best option for breeders seeking superior genetics internationally is to facilitate data exchange and have analysis and reporting done within their own country.

Understanding the interaction of prolactin and leukaemia inhibitory factor signalling during the switch from lactation to involution : Brief Communication - Singh K; Vetharaniam I; Prewitz M; Dobson J; Stelwagen K (Proceedings of the New Zealand Society of Animal Production, 2009)
The molecular mechanisms involved in involution of the bovine udder, a process which underpins lactation persistency, are poorly understood. During rodent lactation, STAT5 is activated in response to prolactin (PRL) to stimulate milk protein production (Liu et al., 1997). At the onset of involution, STAT5 is rapidly inactivated (Schmitt-Ney et al., 1992), and STAT3 is activated by leukaemia inhibitory factor (LIF) to... Continued

Urinary nitrogen excretion from cows at different stage of lactation grazing different ryegrass cultivars during spring or autumn - Pacheco D; Lowe K; Burke JL; Cosgrove GP (Proceedings of the New Zealand Society of Animal Production, 2009)
The effects of season (spring or autumn) and stage of lactation (early or late) on the partitioning of dietary nitrogen (N) between milk and urine were measured in experiments in which cows grazed forages with putative differences in the ratio of water soluble carbohydrates (WSC) to crude protein (CP). Sixty cows (n = 30 for each stage of lactation) grazed one of three forages during spring and autumn. Forage treatments consisted of a 'standard' perennial ryegrass (STG) and two ryegrasses with high WSC concentrations: a perennial 'high sugar' ryegrass (HSG), and an annual ryegrass (IRG). In spring, grass type had a significant effect on the estimated urinary N excretion. Both the HSG and STG resulted in greater N excretion compared to the IRG, due to the low CP concentration in this forage in one of the grazing periods. In autumn, cows grazing STG excreted less urinary N than both HSG and IRG. In both seasons, cows in early lactation secreted more N into milk but were not different in N excretion. In early lactation cows, the extra N in milk was only a small proportion of the potential N intake arising from higher CP content in autumn grasses.

Using an existing intake model to demonstrate relationships between herbage allowance, hunger drive, days in milk and actual intake in grazing dairy cows - Gregorini P; Romera AJ; Beukes PC; Rossi JL; MacDonald KA (Proceedings of the New Zealand Society of Animal Production, 2009)
A sheep intake model was adjusted for dairy cows and used to illustrate intake in relation to inherent hunger, days in milk (DIM), and herbage allowance. Intake is predicted by an exponential function of pregrazing herbage mass, stocking density and hunger drive (k). In adjusting the model, k was re-parameterised using a data set of n = 1,198; it was then adjusted to represent intake decline from peak to end of lactation. This adjustment resulted in splitting k into a and b. Parameter a represented inherent hunger and b its persistence during lactation. The re-parameterised model was tested against an independent data set (n = 287). The square root of mean prediction error was 1.57, indicating good prediction accuracy. Data from three different cow strains, New Zealand-70 and -90 and North American-90 (n = 210, 293 and 271, respectively) were used to reestimate a and b, and to illustrate inherent hunger drive. a and b differed (P <0.01) between strains. Then, with the adjusted and re-parameterized models, the interaction effect of herbage allowance, strain, and DIM on intake were simulated. The adjusted model offers an easy-to-use tool to compare, interpret and illustrate feeding scenarios.

The variation in methane emissions from sheep and cattle is not explained by the chemical composition of ryegrass - Hammond KJ; Muetzel S; Waghorn GC; Pinares-Patino CS; Burke JL; Hoskin SO (Proceedings of the New Zealand Society of Animal Production, 2009)
A data base of over 3,000 ruminant methane emission records from individual animals used to compile New Zealand's greenhouse gas inventory, shows substantial variation in CH4 yields (g/kg dry matter intake (DMI)) within and between forage types. Multiple regression analyses were undertaken using datasets from sheep and cattle fed fresh ryegrass to determine the extent to which variation in CH4 yields could be explained by ryegrass chemical composition. Methane was measured using the SF6 marker dilution technique with sheep and cattle, and also directly by respiration calorimetry from sheep. Data from sheep showed a similar average CH4 yield from both techniques, but there was more variation in SF6 data (23.4 ± 5.73) than from calorimetry (23.1 ± 2.89). Cattle CH4 yields averaged 19.1 ± 3.70 g/kg DMI. Multiple regression analysis of sheep data showed pasture chemical composition accounted for <2% of the variation determined by SF6 and 20% of the variation from calorimetry. Only 13% of the variation in yield from cattle was explained by ryegrass composition, so the majority of variance (>80%) was not explained. We suggest the variation in CH4 emissions is affected by digestive characteristics of individual animals, and interactions with forage physical and chemical components.

Variation of wool between and across the fleeces of composite-breed strong wool sheep in New Zealand - Craven AJ; Ashby MG; Wildermoth JE; Cox NR; Scobie DR; Nixon AJ (Proceedings of the New Zealand Society of Animal Production, 2009)
Many farmers in New Zealand have moved towards using composite-breed sheep flocks to increase the meat production and fecundity of their stock. We aimed to determine whether flocks with a wider genetic base had greater between and within-fleece variation than single-breed flocks. Wool from seventeen body sites of sheep from five flocks of diverse genetic background (Romney, Coopworth, and crosses with Texel, Finnish Landrace and East Friesian breed lines) were compared. Both mean fibre diameter and mean fibre curvature differed between flocks (P <0.001), and across the body (P <0.01). While fibre diameter was more consistent, fibre curvature was more variable across the finer fleeces of flocks with some Finnish Landrace influence. Wool was shorter in Texel crosses, resulting in more consistent length across body sites. Our data suggests that composite-breed sheep exhibit increased within-fleece variation of some wool traits and decreased variation of others. Of most significance was that the extent of wool variation across body sites varied considerably between sheep, regardless of their genotype. In general, there was little association between wool traits with respect to this across-fleece uniformity. Fleece uniformity can be assessed by sampling across the anterior-posterior axis. Selection of stock with more uniform fleeces for specific traits may aid the production of wool better specified to satisfy differentiated niche markets.

Are serum amyloid protein levels in milk an indicator of mastitis infection in New Zealand dairy goats ? - Hodgkinson AJ; Kivits LJ; Molenaar AJ; McDougall S; Prosser CG (Proceedings of the New Zealand Society of Animal Production, 2008)
The incidence of clinical mastitis in dairy goats is low at less than 5% per lactation (Bergonier et al., 2003), however, there is a recognised need in the industry for a simple, practical and reliable means for the detection of sub-clinical mastitis. In goats, conversely to cows, somatic cell counts (SCC) are not a reliable indicator of infection. Bacteriological cultures can be used to identify glands with subclinical infection, but this approach involves specialized sampling. Serum amyloid A (SAA) is a family of acute phase proteins that is produced in response to infection and inflammation. Levels of this protein in milk have been ...Continued

Artificial insemination of red deer (Cervus elaphus) hinds late in the breeding season - Quinn-Walsh EC; Wellby M; Ridgway MJ; Barrell GK (Proceedings of the New Zealand Society of Animal Production, 2008)
Red deer hinds in New Zealand typically conceive around April, however they have spontaneous ovulatory activity extending until September. There is little experience with mating late in the potential breeding season and there is some evidence that they may not be able to achieve pregnancy at this time of the year. The present study determined whether red deer hinds are capable of becoming pregnant following an induced ovulation in August. Ten adult red deer hinds were treated with intravaginal progesterone-releasing devices (CIDRs) and equine chorionic gonadotrophin during May prior to set time artificial insemination or were untreated, non inseminated controls. Ovulation and pregnancy were monitored by measurement of plasma progesterone concentration and rectal ultrasonography, respectively. This procedure was repeated in August. The progesterone data showed that the control hinds experienced spontaneous ovulations on both occasions and that, following CIDR removal, 9/10 and 10/10 treated animals ovulated in May and August respectively. Pregnancy rate at 45 days post insemination was 5/9 and 3/10 animals ovulating in May and August, respectively. Although these results showed modest success of set time artificial insemination following induced ovulation, they clearly indicated that red deer hinds are capable of conceiving successfully late in the breeding season.

Artificial insemination success rates for Meat and Wool New Zealand central progeny test sires - McLean NJ; Dodds KG; Knowler KJ; Jopson NB; Behrent M; Logan CM; Muir PD; Shackell GH; McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2008)
National progeny testing schemes have become important components of national sheep genetic improvement programmes in Australia, France, and New Zealand (Fogarty et al., 2002; Bibé et al., 2002; Campbell et al., 2005). In 2001 the Alliance Central Progeny Test was established, this was combined in 2005 with the Elite Lamb Progeny Test to become the Meat and Wool New Zealand Central Progeny Test (CPT). Over the past six seasons, a total of 120 leading industry sires, comprising 14 different breeds, have been mated via artificial insemination. CPT rams are genetically connected via common sires ...Continued

Association between milk protein concentration and preceding reproductive performance in Holstein-Friesian heifers and cows in Australia - Fahey J; Morton JM; Macmillan KL (Proceedings of the New Zealand Society of Animal Production, 2008)
Milk protein concentration (MP%) has been associated with reproductive performance amongst parous dairy cows. This study aimed to assess whether early lactation MP% of primiparous cows was associated with prior reproductive performance, and to compare the strength of the association between MP% and previous reproductive performance in nulliparous heifers with that in multiparous cows. Primiparous (n = 918 in 35 herds) and multiparous (n = 4,242 in 64 herds) Holstein-Friesian cows with milk production/composition records and sire genetic information in seasonally calving herds were selected from the InCalf database. The date for each herd’s planned start of calving (PSC) was calculated as being 282 d after the date breeding started. The interval between a herd’s PSC date and each cow’s actual calving date (PSC - CI) will therefore reflect time to conception during the previous breeding period. Higher MP% was positively associated with shorter PSC-CI in both primiparous and multiparous cows. Across the range of cows that had a MP% that was ± 0.5% of the herd’s mean MP%, those with the lowest MP% had an average PSC-CI that was either 13 d or from 28 to 32 d later in primiparous or multiparous cows, respectively. These associations were likely due to biological determinants present before and during the cow’s breeding period that were associated with both reproductive performance and subsequent MP%. Since these determinants affected the reproductive performance of non-lactating heifers, some of the associations with MP% were not related to lactation-specific factors even though these same factors may have increased the effect of low MP% on the reproductive performance of the multiparous Holstein-Friesian cows.

Carcass and meat quality characteristics in young deer stags of different growth rates - Wiklund E; Asher GW; Archer JA; Ward JF; Littlejohn RP (Proceedings of the New Zealand Society of Animal Production, 2008)
Fourteen male yearling red deer from the same cohort were included in this study. Seven of these animals were fast growing and reached slaughter live weight in late June (fast growing group), while the second group of seven deer did not reach slaughter live weight until early December (slower growing group). All animals were slaughtered according to standard protocol. Carcass composition was determined by computed tomography scanning. Water-holding capacity, meat pH, tenderness and sarcomere length were measured in samples (M. longissimus) at 1 day post slaughter and in samples kept in chilled storage at -1.5 °C for three weeks. Eating quality of the meat was evaluated in consumer preference tests. Slower growing deer were heavier (P = 0.02) and had more fat in the shoulder (P = 0.01) and loin (P = 0.001) cuts than fast growing deer. Meat from fast growing deer had lower pH values (P = 0.01), lower cooking loss (P = 0.04) and longer sarcomere lengths (P = 0.002) than slower growing deer. Consumers judged the flavour of venison from fast growing deer to be best (P = 0.005), although interactions between the sensory attributes and the consumer`s experience of venison affected their assessment.

Characterization and establishment of embryonic stem cell - like cell lines from in vitro produced buffalo (Bubalus bubalis) parthenotes - Verma V; Chauhan MS (Proceedings of the New Zealand Society of Animal Production, 2008)
Embryonic stem cells (ESC) provide potentially unlimited cell numbers for gene targeting, providing great value to agriculture and medicine. This study was conducted to isolate and characterize parthenogenetic ESC (pESC)-like cells from in vitroproduced buffalo parthenotes. A total of 100 blastocysts were produced through chemical activation. For pESC culture, 20 blastocysts were left intact, while the rest was dissociated mechanically or enzymatically, to isolate inner cell mass (ICM) cells from 44 hatched and 36 non-hatched blastocysts, respectively. ICM cells were seeded and cultured on mitomycin-C treated feeder layers of buffalo fetal fibroblasts. Primary cell colonies formed three tofour days after ICM seeding. Colony formation was significantly lower from intact blastocysts (3/20 (15%)) than from ICM cultures (39/80 (49%)) with hatched blastocysts being better starting material than non-hatched ones (30/44 (68%) versus 9/36 (25%), respectively). Up to passage nine, two mechanically isolated pESC-like lines remained viable and expressed specific markers such as alkaline phosphatase activity, as well as Nanog and Oct-4 mRNA. Cells formed embryoid bodies in suspension culture. It has been shown it is possible to isolate buffalo pESC-like cells from parthenogenetically developed embryos and maintain the culture in vitro for a prolonged period of time.

Comparative methane emissions from cattle, red deer and sheep - Swainson NM; Hoskin SO; Clark H; Pinares-Patino CS; Brookes IM (Proceedings of the New Zealand Society of Animal Production, 2008)
Methane (CH4) production (g CH4/d) and yields (g CH4/kg dry matter intake (DMI)) from groups of 11 non-lactating dairy cattle, sheep and red deer were compared in January and June of 2007. During each period, methane emissions measured using the SF6 tracer technique, were measured over four days following 10 days of acclimatisation. All animals were individually housed in metabolism cages and fed ensiled lucerne chaff at a rate of 1.2 times estimated energy requirements according to Australian feeding standards. Total daily methane production from cattle (140.4 g CH4/day) was greater than deer (31.5 g CH4/day) which was greater than sheep (18.3 g CH4/day) (P<0.001) and methane yield from cattle (20.6 g CH4/kg DMI) was greater than sheep (18.4 g CH4/kg DMI) which was greater than deer (16.5 g CH4/kg DMI) (P<0.001). A significant interaction of species by season was driven by the higher methane production and yield of cattle in winter compared with summer (P<0.001). The findings of this experiment show that methane emissions can differ between ruminant species at the same time on the same diet. Reasons for these differences are yet to be elucidated.

Comparison of lameness and hoof horn puncture resistance of New Zealand Friesian and Jersey cross Friesian dairy cattle - Lethbridge LA; Margerison JK; Reynolds GW; Laven R; Brennan CS (Proceedings of the New Zealand Society of Animal Production, 2008)
Sole lesions have been found to be one of the most common causes of lameness in both New Zealand (Chesterton, 2004) and the United Kingdom (Logue, 1999). In most studies it was found that these hoof horn lesions develop in postpartum animals and in hind claws (Greenough & Vermunt, 1991) and that these are associated with a significant reduction in the puncture resistance of the hoof (Winkler & Margerison, 2006). There has been some reference to lower levels of lameness occurring in Jersey and Jersey cross bred cattle, compared with Holstein Friesian dairy cattle ...Continued

Comparison of mastitis prevalence between an organic and conventional dairy herd from 2004 to 2006 - McLeod KLM; Holmes CW; Morel PCH; Dowson KR; Thatcher A; Shadbolt NM; Kelly TC (Proceedings of the New Zealand Society of Animal Production, 2008)
This study compared mastitis bacteriology and somatic cell counts (SCC) between an organic and a conventional dairy herd, each managed as a pastoral-based system, in the 2004/05 and 2005/06 seasons. Single quarter foremilk samples taken from both herds at calving, 14 days post-calving, mid-lactation and dry-off were cultured for bacteriological analysis. Individualcow SCC were obtained from monthly herd tests. The percentage of cows infected with Staphylococcus aureusand Streptococcus uberiswas generally higher in the organic herd than the conventional herd. However, these differences were only significant for S. aureusat midlactation 2005/06, when 56% of the organic herd was infected compared to 23% of the conventional herd (P <0.05), and for Str. uberisat dry-off 2005/06, when 7% of the organic herd was infected but none of the conventional herd (P <0.001). The organic herd had a significantly higher mean lactation back transformed SCC than the conventional herd, in 2004/05 (96,921 vs. 75,608 cells/mL, P <0.05) and 2005/06 (103,968 vs. 63,096 cells/mL, P <0.0001). The 2004/05 season was the first time that a significant difference in mean SCC between the organic and conventional herds had been measured, since the organic and conventional dairy systems comparison trial was established in 2001.

Comparison of Romney sheep selected for different roundworm parasite-related traits - Wheeler M; Morris CA; Bisset SA (Proceedings of the New Zealand Society of Animal Production, 2008)
Romney sheep selected for resistance to nematode infection, resilience to nematode challenge, or an index combining these traits, were evaluated alongside an unselected control line. Data from lambs born between 2000 and 2006 were analysed. Lambs grazed together, within sexes, while exposed to natural parasite challenge of predominantly Trichostrongylus sp. and Teladorsagia sp. Relative to the Control, the Resilient line was heavier at weaning (+7.6%) and in autumn (+14.5%), had 5.6% higher yearling greasy fleece weight (YGFW), and less dags (lower score) at 5 months of age by 0.72 standard deviations (SD) (all P <0.01). As expected, the two lines had similar post-weaning faecal worm egg count (FEC1). Compared with the Control, the Resistant line was lighter at weaning (-8.6%) and in autumn (-8.0%), had 14.9% lower YGFW and a higher dag score by 0.22 SD, whilst FEC1 averaged 16% of the Control value (all P <0.001). Performance of the Index line in growth and YGFW was 3.5 to 6.8% above that expected in a Resistant x Resilient cross. Conversely, FEC1 in the Index line was at least 31% higher than expected for a cross. We conclude that combining genes for resilience and low FEC by index selection is feasible.

Counting infective-stage nematode larvae in rumen fluid as an indicator of parasite challenge in grazing sheep - Litherland AJ; Deighton DL (Proceedings of the New Zealand Society of Animal Production, 2008)
The aim of this study was to evaluate rumen fluid sampling as a novel method for quantifying nematode challenge encountered by grazing sheep. In Experiment 1, rumen fluid samples were seeded with known numbers of third stage infective larvae (L3) of Teladorsagia circumcincta, Trichostrongylus colubriformis and Cooperia curticei. Immediate recovery rates averaged 92% (Coefficient of variation, 13%), 53% (15%) and 50% (30%) for each species respectively. Recovery rates from rumen fluid stored at 7°C decreased to 44% (29%), 33% (18%) and 0% (0%) after 72 hours. In Experiment 2, 15 ewe hoggets maintained indoors were dosed with 5,000 L3 T. circumcincta and 5,000 L3 T. colubriformis. At 1, 2 and 12 hours after dosing the numbers of L3 recovered from the rumen fluid were 0.2 (125%), 0.16 (145%) and 0.01 L3/mL (300%) respectively. In Experiment 3, rumen fluid samples were taken from small groups of lambs grazing four paddocks with variable herbage infestation rates of mixed species of L3. Species composition of L3 on the herbage and in the rumen fluid was T. circumcincta 8% and 0%; T. colubriformis 27% and 19%; C. curticei 0% and 5%; Nematodirus spp. 63% and 69% and Haemonchus contortus 2% and 9%. A significant number of technical challenges remain before the method has a practical application.

Does calf genotype influence milk yield of red deer hinds ? - Ward JF; Archer JA; Asher GW; Barrell GK; Littlejohn RP (Proceedings of the New Zealand Society of Animal Production, 2008)
New Zealand deer farming systems utilise Cervus elaphus subspecies and crossing genotypes is a common tool to gain a productive advantage. One of the most common crosses is that of a stag with a high content of North American Wapiti (C. e. manitobensis, nelsoni, roosevelti) over the traditional New Zealand (NZ) red hind of English or Scottish origin (C. e. scoticus) for venison production, with on the aim of attaining slaughter live weight ...Continued

Economic modelling of the comparative performance of Jersey x Holstein - Friesian crossbred cows in Victorian Holstein-Friesian herds - Pyman MF; Malcolm W; Macmillan KL (Proceedings of the New Zealand Society of Animal Production, 2008)
An economic model was developed to compare two different farm systems using the production results and reproductive performance figures derived from an observational study of 14 seasonally calving dairy herds in Victoria. The farm systems modelled were a crossbred herd comprising Jersey x Holstein-Friesian and Holstein-Friesian x (Jersey x Holstein-Friesian) breed types and a herd of Holstein-Friesian cows with farm operating profit as the outcome. A direct comparison of the two farming systems demonstrated a clear advantage in operating profit that averaged A$21,194 for the 267 cows in the crossbred herd compared to the 252 cows in the Holstein-Friesian herd. The difference in profit was due to the higher potential stocking rate of the crossbred herd (2.27 vs 2.15 cows/ha) because of their lower live weight (1 crossbred cow = 0.93 Holstein-Friesian cow) and superior reproductive performance (84% vs 77% pregnancy rate after 14 weeks) resulting in longer survival and reduced investment in replacement rearing costs.

Effect of dietary protein on liveweight gain in parasitised cows - Burggraaf VT; Puha MR; Adler AA (Proceedings of the New Zealand Society of Animal Production, 2008)
The interaction between parasitism and crude protein (CP) nutrition on calf liveweight gain (LWG) was investigated. One hundred and twelve calves were either administered 21,000 parasite larvae (73% Cooperia oncophora, 16% Ostertagia ostertagi, 11% Trichostrongylus axei) twice per week or drenched fortnightly with anthelmintic for 12 weeks. Calves grazed ryegrass pastures and received 40% of their diet as either low (15% CP) or high (26% CP) protein pellets. Half of the calves switched diets after six weeks. All treatments averaged a liveweight gain of at least 1 kg/d. After 12 weeks non-parasitised calves were 13 (standard error of difference (SED 2.0)) kg heavier than parasitised calves (P <0.001), and calves fed a high protein supplement were 12 (SED 2.8) kg heavier than those fed low protein supplement (P <0.001). There was no interaction between diet and parasitism (P = 0.74). Subsequentlycalves grazed together for a further 12 weeks with no supplements or parasite dosing. The liveweight advantage of the high protein supplement was lost, while non-parasitised calves maintained a liveweight advantage of 15 (SED 4.9) kg (P <0.01). While protein supplementation did not affect faecal egg count or blood pepsinogen it has the potential to improve LWG with less reliance on anthelmintics under field conditions.

Effect of dry cow management on teat end bacterial contamination - Turner S-A; Williamson JH; Lacy-Hulbert SJ (Proceedings of the New Zealand Society of Animal Production, 2008)
Two stock management practices were investigated for their effect on transfer of bacteria from the environment onto teat ends of dry dairy cows. Cows (n = 20) were required to walk or trot along races (1.2 km) deemed to be "clean" or "dirty". Cows walked along "clean" or "dirty" races were similar in dirtiness of the udder, and bacterial loading of the teats. Cows that trotted along `dirty` races showed a significant increase in degree of dirtiness of the teats and legs, and increased contamination of teats with coliform bacteria. Cows grazed for 24 hour periods using standard break-fencing systems, with (n = 20) or without (n = 20) the addition of back-fencing were assessed for the number and type of bacteria present on teat-ends. Cows that grazed paddocks with back-fencing had visually dirtier udders, but there was no difference in bacterial contamination of teats compared to those cows grazed without back-fencing. These studies suggest that the risk of bacterial contamination, and by extrapolation, risk of intra-mammary infection, may be mitigated by the speed with which cows are moved along races. However, grazing on muddy, soiled paddocks should not be discounted as a significant risk factor for mastitis.

Effect of forage allowance and forage system during the dry period on the performance of dairy cows - Keogh BK; French P; McGrath T; Storey T; Mulligan FJ (Proceedings of the New Zealand Society of Animal Production, 2008)
Sixty multiparous Holstein-Friesian dairy cows were allocated one of three forages (fodder beet, kale or grass silage) at one of two feeding allocations (high and low). Cows offered the high allowance system received 9 kg of kale or fodder beet DMin-situplus 5 kg of bale grass silage DM per day,or ad libitumgrass silage offered indoors. Cows on the low allowance system were offered 6 kg of kale or fodder beet DMin-situplus 3.5 kg of bale grass silage DM per day,or 9.5 kg of grass silage DMoffered indoors. Treatments were imposed for 70 ± 16 days before parturition. Post-partum,all cows were turned out to pasture and received 14 kg of perennial ryegrass DM plus 4 kg of concentrate/cow/d for the first five weeks of lactation. Cows offered grass silage had a greater gain in body condition score pre-partum than animals offered kale or fodder beet systems. Cows offered the fodder beet system pre-partum had a greater fat yield compared to those offered kale and a greater protein yield compared to those offered grass silage, resulting in a 9 % increase in solids corrected milk yield during the first five weeks of lactation.

Effect of genotype and concentrate supplementation on dairy product mix and the value of milk produced by grazing dairy cows during an extended lactation - Turner S-A; Phyn CVC; Kolver ES; Aspin PW; Lopez-Villalobos N (Proceedings of the New Zealand Society of Animal Production, 2008)
Dairy product mix and milk value were investigated in Holstein-Friesian cows of New Zealand or overseas origin that grazed pasture and were supplemented with 0, 3 or 6 kg DM concentrate/cow/day during a 600-day extended lactation. A dairy product supply chain model was used to predict relative changes in dairy product mix and milk value during the "extended period" (300 to 600 days in milk) compared with the "normal period" (0 to 300 days in milk). Cow genotype and level of concentrate supplement affected dairy product yields, with little consistency of effect between "normal" and "extended" periods. Milk produced during the "extended period" resulted in more cheese, butter, butter milk powder, casein, and whey protein concentrate, but less whole milk powder, skim milk powder and whey milk powder compared to the "normal period". The overseas strain and those cows receiving higher levels of concentrates had less of a decline in whole milk powder yields associated with the "extended period". Milk value ($/L), was predicted to be 20.8% higher during the "extended period" compared with the "normal period". These results indicate that extended lactations may improve the dairy product mix and milk value following processing.

Effect of genotype and diet on feed conversion efficiency of dairy cows during a 600-day extended lactation - Phyn CVC; Clark C; Aspin PW; Kolver ES (Proceedings of the New Zealand Society of Animal Production, 2008)
This study investigated the effect of genotype and diet on the gross feed conversion efficiency (FCE) of cows milked for 600-day extended lactations (24-month season) compared with 300-day lactations (12-month season). North American (NA) and New Zealand (NZ) Holstein-Friesians (HF) grazed pasture and were supplemented with either 0, 3 or 6 kg DM concentrate/cow/day. In a normal 12-month season, gross FCE was greater for NZ HF compared with NA HF cows when fed 0 or 3 kg DM concentrate (96 and 104 vs. 90 and 99 kg milksolids (MS)/t dry matter intake (DMI), respectively), but similar when fed 6 kg DM (101 kg MS/t DMI). However, during an extended 24-month season, NZ HF cows had a lower gross FCE than NA HF when fed 6 kg DM concentrate (86 vs. 99 kg MS/t DMI, respectively) and similar FCE when fed 0 or 3 kg DM (85 and 94 vs. 86 and 99 kg MS/t DMI, respectively). Regardless of diet, gross FCE in an extended lactation was 98% of that obtained in a normal season for NA HF cows, but only 88% for NZ HF, indicating that NA HF are better suited to converting feed into high MS production in extended lactations.

Effect of MyoMAX on carcass lean and fat - Bain WE; PL Johnson; Greer GJ; Dodds KG; McLean NJ; McLaren RJ; Galloway SM; Van Stijn TC; McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2008)
Previous research has identified quantitative trait loci (QTL) for increased lean meat yield and decreased fat in similar regions of sheep chromosome 2, in New Zealand and Belgian Texels (Broad et al., 2000; Johnson et al., 2005; Laville et al., 2004; Marcq et al., 2002). In the case of the Belgian Texels it has been demonstrated that a single G to A transition ...Continued

Effect of offering differing levels of milk and plant extracts on feed intake , growth and development of New Zealand Holstein-Friesian and Jersey crossbred dairy cattle - Margerison JK; Lethbridge LA; Reynolds GW (Proceedings of the New Zealand Society of Animal Production, 2008)
Calving dairy heifers at 2 years of age at 85 to 90 % of their mature live weight and being mated at 65% of their mature live weight, has been found to increase lifetime productivity (Margerison & Downey, 2005). Recent research has focused on increasing dairy calf liveweight gain and development, while minimising body fat deposition, particularly in mammary parenchyma (Sejrsen, 2005; Brown et al., 2005), by increasing feeding levels during the prepubertal period with differing sources and levels of energy and protein, and the use of probiotics and natural plant extracts to replace antimicrobials (Hill, 2005; Tannan, 2005). The aim of this research was to ... Continued

Effect of once daily milking on milk flavour chemistry - Lane GA; Fraser K; Yu M; Pacheco D; Dalley DE; Hofmann LA (Proceedings of the New Zealand Society of Animal Production, 2008)
Indole and skatole have been associated with the "pastoral" flavour of New Zealand dairy products (Bendall, 2001). They occur at elevated levels in milk from pasture-fed cows in New Zealand, particularly in early to mid spring (Lane et al., 2002). On-farm management approaches to control skatole levels in milk could provide benefits to the industry for particular products and ...Continued

The effect of palm kernel expeller as a supplement for grazing dairy cows at the end of lactation - Dias FN; Burke JL; Pacheco D; Holmes CW (Proceedings of the New Zealand Society of Animal Production, 2008)
Palm kernel expeller (PKE) is a solid byproduct from the palm oil. In New Zealand it is used as a supplementary feed on dairy farms to fill short term pasture deficits and according to MAF (2007), over 350,000 tonnes of PKE was imported into New Zealand during 2007. Despite its growing use as a feedstuff for ruminants in New Zealand, information is scarce about the nutritional value of PKE and ...Continued

Effects of facial eczema on skatole detoxification efficiency in dairy cows - Fraser K; Lane GA; Yu M; Morris CA; Cullen NG (Proceedings of the New Zealand Society of Animal Production, 2008)
Facial eczema (FE) is a disease caused by the fungal toxin sporidesmin, which upon ingestion by dairy cows can cause liver damage in susceptible animals. Skatole is formed in the rumen by the breakdown of dietary protein, absorbed into blood and is cleared by metabolism in the liver to 3-methyloxindole (MOI) and 3-hydroxy-3-methyloxindole (HMOI) and products of further oxidation and conjugation. In this study we have determined the concentrations of skatole, MOI and HMOI in the blood of dairy cows selected for their "high" gamma-glutamyltransferase (GGT) and "low" GGT in autumn and spring. Significant differences in skatole and MOI median concentrations were found in the autumn blood between the high and low GGT groups (skatole: 11.9 and 1.1 ng/mL respectively, P <0.001; MOI: 23.9 and 11.9 ng/mL respectively, P <0.05) although there was no difference in blood HMOI levels. Similar trends were observed for animals with high GGT in both autumn and spring when compared to low autumn and spring GGT. Animals with high autumn GGT and low spring GGT also contained increased median concentrations of skatole and MOI in the spring blood compared to the low autumn and spring GGT group, suggesting a lingering effect of FE damage on liver detoxification efficiency not detected by measuring spring GGT levels.

Energy rather than protein content of hind intake determines growth rate of reed deer calves - Scott IC; Archer JA; Asher GW; Stevens DR; Ward JF; Littlejohn RP; Lach JE (Proceedings of the New Zealand Society of Animal Production, 2008)
Live weight gain of red deer within the first 3 to 4 months of their life plays a major part in determining the efficiency of venison production systems. Over this period young deer are largely dependant on their dam for nutrition. It is often difficult to achieve growth rates greater than 400 g/d in New Zealand because red deer lactation coincides with deteriorating pasture quality. However, calf growth rates of up to 700 g/day have been achieved over late lactation when

Epidemiology of Johne's disease in farmed red deer ( Cervus elaphus ) in New Zealand - Mackintosh CG (Proceedings of the New Zealand Society of Animal Production, 2008)
Johne`s disease, caused by Mycobacterium avium subsp paratuberculosis (M. ptb), has emerged as a significant cause of losses on deer farms in New Zealand. It causes outbreaks of fatal clinical disease in young deer eight to 15 months of age, sporadic deaths in adults and production losses due to poor growth rates in yearlings, reduced calving percentages in hinds, reduced velvet production in stags, interference with tuberculosis testing and tuberculosis-like lesions in gut lymph nodes at slaughter. Although bovine and ovine strains have been isolated from deer, the bovine strain is more pathogenic and is responsible for the outbreaks of serious disease in young deer. Clinical disease results from heavy early challenge of young deer with the bovine strain. Mature animals are relatively resistant to infection. Calves are generally infected via the oral route from contaminated pasture and water. Intrauterine transmission to the foetus occurs commonly in clinically and subclinically infected hinds and infected milk may also play a role in transmission. Deer-to-deer transmission appears the most common route, although cattle-to-deer and sheep-to-deer transmission may occur. The role of wildlife is not known. Resistance to Johne`s disease has a genetic component, which appears to be related to resistance to bovine tuberculosis.

Expression of innate immune response genes in mammary epithelia following stimulation of lipopolysaccharide or Escherichia coli - Stockum C; Haigh BJ; Meyer HHD; Bruckmaier RM; Wheeler TT; Singh K (Proceedings of the New Zealand Society of Animal Production, 2008)
The innate immune system is essential for keeping the bovine mammary gland disease free. A number of innate immune response genes are expressed in bovine mammary epithelial cells (bMEC), suggesting it contributes to defence against pathogens (Rainard & Riollet, 2006). These responses may play a key role in determining susceptibility to mastitis. The aim of this project was to investigate the expression in bMEC of specific innate immune genes in response to Escherichia coli ...Continued

Factors affecting colour stability of fresh chilled lamb meat - PL Johnson; McLean NJ; Bain WE; Young E; Campbell AW (Proceedings of the New Zealand Society of Animal Production, 2008)
An increasing proportion of New Zealand lamb meat is shipped to the European Union market as chilled rather than frozen product, with 29% exported as chilled product in 2005/06 (Anon, 2006). Once chilled lamb reaches this market it is further processed, with the lamb meat entering the retail market approximately eight weeks after slaughter. A major selection criterion for retail purchasers is the colour of the meat on display. Most consumers prefer bright red ...Continued

Field test of production traits in genetically correlated with zearalenone resistance in sheep - Amyes NC; Morris CA (Proceedings of the New Zealand Society of Animal Production, 2008)
Zearalenone is a naturally occurring toxin from the Fusarium fungus which grows on pastures in autumn. The toxin has been found in New Zealand from Northland to Southland (Garthwaite et al., 1994), but high concentrations are particularly common in the Gisborne/East Coast region. The toxin interferes with reproductive function in susceptible sheep (Smith et al., 1986), reducing fertility, ovulation rates and thus lambing percentages. Under research conditions with Romney sheep at Ruakura Research Centre, we have developed a protocol ...Continued

Gene expression profiling of wool follicle growth cycles by cDNA microarray - Yu Z-D; Gordon SW; Pearson AJ; Henderson HV; Craven AJ; Nixon AJ (Proceedings of the New Zealand Society of Animal Production, 2008)
Wool growth in Wiltshire sheep was synchronised by daylength manipulation to allow identification of genes that are regulated during transitions in the wool follicle cycle. Pair-wise comparisons between growing and resting phases were conducted using both direct and indirect cDNA microarray analysis. The two approaches were well correlated at three different levels: overall similar patterns of gene expression, detection of changes in keratin gene expression, and reduced differential expression between closer cycle stages. Using more slides, the indirect approach identified more expressed sequence tags (ESTs) (indirect 1132, direct 444), and had higher coverage of wool keratins (indirect 78%, direct 42%). This study demonstrates the usefulness of cDNA microarray for expression profiling in whole skin. Further characterisation of genes identified by this work, particularly the smaller sets of ESTs derived from comparisons at early stages of follicle regression and regrowth, would improve our understanding and provide leads for alternative wool harvesting technology or enhancing wool growth.

Genetic parameters for growth in Wapiti deer farmed in New Zealand - Archer JA; Ward JF; Fisher PJ; Glass BC (Proceedings of the New Zealand Society of Animal Production, 2008)
The New Zealand deer industry commonly uses "Wapiti" type deer as terminal sires mated to "red" hinds in venison production systems. The terms "Elk" and "Wapiti" are commonly used almost interchangeably in the New Zealand deer industry to describe subspecies of red deer originating in North America (Cervus elaphus subspecies manitobensis, roosevelti and nelsoni). These subspecies are approximately twice the mature body size of "red" deer ...Continued

Genetics of residual energy intake in Irish grazing dairy cows - Lopez-Villalobos N; Berry DP; Horan B; Buckley F; Kennedy J; O'Donovan M; Shalloo L; Dillon P (Proceedings of the New Zealand Society of Animal Production, 2008)
The objective of this study was to investigate the genetics of residual net energy intake (RNEI) in grazing Holstein-Friesian cows. RNEI was defined as net energy intake minus predicted net energy requirements using the unité fourragère lait (UFL) system. Net energy intake from grass and concentrate was estimated up to four times per lactation on 1,111 lactations from 463 cows on an experimental farm in Southern Ireland. Grass dry matter intake was estimated using the n-alkane technique. Lactation curves for milk, fat, protein, lactose and live weight were modelled with splines using weekly measures. A random regression was used to estimate residual, additive genetic and permanent environmental variances for RNEI and breeding values at Day 60 for each cow. Heritability for RNEI across lactation varied from 0.05 at 30 days in milk to 0.38 at 296 days in milk. Genetic parameters for RNEI obtained in this study are in agreement with those obtained under indoor conditions. Comparative performance between cows of low and high RNEI breeding value at Day 60 agrees with results obtained in beef cattle selected for high or low residual feed intake showing similar productivity but higher feed conversion efficiency in cows selected for low residual feed intake.

Heritability of IGF-1 and its genetic correlation with milk yield in Holstein-Friesian cows in selected Victorian herds - Stirling TE; Stockdale CR; Macmillan KL (Proceedings of the New Zealand Society of Animal Production, 2008)
Insulin-like growth factor-1 (IGF-1) is a small peptide, produced mainly in the liver. It controls the growth and differentiation of many cell types through stimulation of the cell cycle (Rechler & Nissley, 1990). IGF-1 has been implicated as being involved in many biological processes and is thought to be related to milk production and reproductive potential of the dairy cow due to its association with the partitioning of nutrients among biological functions (Bauman & Currie, 1980) and its direct stimulatory affect on the ovaries (Spicer et al., 1993). ...Continued

High crude protein in autumn pasture does not impair reproductive performance in sheep - Madibela OR; Nicol AM; Sykes AR; Jay NP (Proceedings of the New Zealand Society of Animal Production, 2008)
Embryos exposed to ammonia may degenerate or their growth enhanced (McEvoy et al., 1997). Kelly (1982) reported reproductive wastage of 24.9% in South Island sheep. New Zealand pastures contain high concentrations of crude protein (Chaves et al., 2002) but whether reproductive wastage can partly be explained by ammonia and/or urea toxicity from high protein pasture is unknown. The aims of the present study were to determine the effect of plasma urea concentration on ovulation rate, embryo survival, conception rate and lamb birth weight in ewes joined with the ram on ...Continued

Indicators for early detection of ecchymosis ( blood splash ) in fallow deer ( Dama dama ) carcasses - Mulley R; Wiklund E; Falepau D (Proceedings of the New Zealand Society of Animal Production, 2008)
Ecchymosis is a haemorragic syndrome that appears as small dark spots on the surface of various muscles of a carcass and some organs. It is considered a meat quality defect. In this study eight fallow deer carcasses were completely dissected. Hindquarter muscles showed a significantly higher incidence of ecchymosis compared with forequarter muscles. The most affectedmuscles were the primal cuts from the hindquarter including the striploin. When this information was applied to a wider study of 963 fallow deer carcasses 23.1% had low to moderate ecchymosis in the left round (M. vastus lateralis). In all cases this muscle was a reliable indicator of the presence of ecchymosis in the loins and/or other hind leg primals. In the same carcasses visceral organs such as lung and heart were unreliable indicators of the presence of ecchymosis in skeletal muscles. Castrated bucks were most likely to exhibit ecchymosis followed by does and bucks (P = 0.02).An on-line inspection system for fallow deer was recommended which included an in situinspection of the left round as an accurate means of determining ecchymosisincidence in other valuable commercial cuts.

Indole and skatole as markers for nitrogen utilisation in dairy cows - Pacheco D; Lane GA; Fraser K; MacDonald KA; Back PJ (Proceedings of the New Zealand Society of Animal Production, 2008)
Indole and skatole are products of amino acid degradation in the rumen which could be useful to monitor protein utilisation in grazing ruminants. Two groups ("1970s" strain and "current" strain) of mixed age Holstein Friesian cows were housed indoors and fed cut pasture for 21 days. Concentrations of indole and skatole in milk fat and of milk urea nitrogen were determined. No significant differences were observed between strains of cow for indole and skatole concentration in milk fat, but they were different (P<0.01) between sampling dates. Both indole and skatole had moderate positive (r ~0.50) correlation with the rumen degradable protein (RDP) balance, whilst skatole had a weaker (r ~0.30) correlation with crude protein intake, metabolisable protein supply and RDP supply. Indole and skatole concentrations in milk fat were more closely correlated to the estimated RDP balance in the rumen than milk urea. A large proportion of individual animal variation in milk metabolites remains unaccounted for by protein intake, and may relate to individual differences in detoxification and elimination of indole and skatole.

Inheritance of chondrodysplasia in Texel sheep - Byrne TJ; Blair HT; Thompson KG; Stowell KM; Piripi S (Proceedings of the New Zealand Society of Animal Production, 2008)
A skeletal chondrodysplasia (noncancerous abnormal cell growth affecting cartilaginous tissues) characterized by dwarfism and angular deformity of the forelimbs has been recognized in Texel and Texel cross lambs. Some affected lambs have normal co-twins indicating the disease is likely to be of genetic origin. This study outlines the mode of inheritance of the disorder. Three affected rams were mated to 221 unaffected ewes to generate 123 daughters, which were backcrossed by multiple sire mating with their sires the subsequent season to produce 83 lambs for evaluation. The time course of the morphological progression of the disease was recorded. Of the 46 lambs that were successfully diagnosed, 22 were affected with the condition and 24 were unaffected. This was consistent with a 50:50 ratio expected for recessive inheritance in a backcross between affected and carrier animals. Within sexes, 11 males (24%) and 11 females (24%) were affected with 10 males (22%) and 14 females (30%) were unaffected. This was not different (P<0.05) from a 0.25 proportion for autosomal recessive inheritance. Variation in the age of onset (16 days ± 7 days) and severity of clinical expression suggests variable penetrance, with semi-lethality.

Jersey cows milked once-a-day can produce 1,200 kg milk solids per hectare - Dalley DE; Clough JW; Hofmann LA; Phyn CVC; Clark DA (Proceedings of the New Zealand Society of Animal Production, 2008)
While dairy cows are generally milked twice-a-day (TAD) in New Zealand, more farmers are adopting a once-a-day (OAD) milking routine to improve their lifestyle, reduce farm costs and improve animal welfare. Clark et al. (2006) reported that the yield of milksolids (MS) from Jersey cows was less affected (-19.9%/cow) by OAD milking than the MS yield from Holstein-Friesian cows (-29.4%/cow). Jersey cows milked OAD in Taranaki between 2000 and 2004 averaged 222 kg MS/cow and 979 kg MS/ha (Clark et al., 2006). In the 2006/07 season average per cow production from cows milked TAD in New Zealand was 330 kg MS ...Continued

Liveweight and body condition of single- and twin-bearing Merino ewes - van Reenen EH; Kenyon PR; Sherlock RG; Hickson RE; Morris ST (Proceedings of the New Zealand Society of Animal Production, 2008)
While dairy cows are generally milked twice-a-day (TAD) in New Zealand, more farmers are adopting a once-a-day (OAD) milking routine to improve their lifestyle, reduce farm costs and improve animal welfare. Clark et al. (2006) reported that the yield of milksolids (MS) from Jersey cows was less affected (-19.9%/cow) by OAD milking than the MS yield from Holstein-Friesian cows (-29.4%/cow). Jersey cows milked OAD in Taranaki between 2000 and 2004 averaged 222 kg MS/cow and 979 kg MS/ha (Clark et al., 2006). In the 2006/07 season ...Continued

Luteal function in pregnant and non-pregnant non-cycling inseminated cows ( Phantom cows ) - Bowyer-Smyth JM; Malmo J; Macmillan KL (Proceedings of the New Zealand Society of Animal Production, 2008)
Cows that do not return to oestrus within 24 days of insemination but are retrospectively diagnosed as not pregnant (non-return, non-pregnant or "Phantom" cows), frequently have a functional corpus luteum (CL) that does not regress. In this study, luteal function around the time of pregnancy diagnosis was compared between pregnant cows and "Phantom" cows with a CL. Cows in two dairy herds that had not returned to oestrus following first insemination were pregnancy tested by ultrasound 5 weeks after insemination. Final analyses included 17 pregnant cows that were cycling normally before being inseminated (CYCP); 22 pregnant cows that had been treated for anoestrus (ANP); and 11 "Phantom" (PC) cows that had not cycled since first insemination and were not pregnant. Blood and CL samples that were collected from each cow between 34 and 38 days after first insemination were assayed for progesterone (P4). Luteal P4 concentrations were similar in pregnant and PC cows (101.6 ± 9.9, 100.7 ± 8.9 and 98.9 ± 12.4 ng/mg for CYCP, ANP and PC cows). Plasma P4 concentrations were also similar (8.5 ± 0.5, 7.6 ± 0.4 and 7.1 ± 0.6 ng/mL) for CYCP, ANP and PC cows. The absence of a return to oestrus in this group of PC cows was most likely related to pregnancy recognition being followed by embryo death and then associated with a failure of luteolysis.

Policy decision framework for conflicting world views on animal welfare issues - Parminter TG (Proceedings of the New Zealand Society of Animal Production, 2008)
Animal welfare policies deal with complex issues involving and resulting from, animal management in highly modified environments. How people consider and respond to animal welfare issues is value laden, constrained by the social norms of their peer-groups and influenced by conflicting scientific and popular opinions. In some cases, achieving a consensus about what constitutes the most socially desirable course of action to follow will simply not be possible. Instead, socially-resilient policies forged from mutual respect and understanding may be possible by bringing together the different world views of the conflicting parties in a planning model that enables them each to contribute transparently towards policy formulation. The 4-windows strategy for animal welfare policy formulation described in this paper, when applied to a farming practice of concern, such as lamb castration, can assist an agency like the National Animal Welfare Advisory Committee to address the concerns of social groups outside of traditional scientific thinking and enable them to contribute to the policy process more fully. However, the 4-windows strategy may be more difficult when there is a lack of reliable information about the values and expectations of some social groups. Overall, this approach has implications for the way in which livestock farming in New Zealand may be influenced in the future by current social trends.

Presidential Address 2007: The Society's role in being empathetic to the animal production industry - Burke CR (Proceedings of the New Zealand Society of Animal Production, 2008)
Mark Twain once said, "Its better to keep your mouth shut and appear stupid...than to open it and remove all doubt". I considered my strength as President to be more of stewardship than visionary. Alas, it is with some risk to fulfilling Mark Twain’s prophecy that I continue with this address. I referred to some of the previous Presidential Addresses; to get a feel for what was expected. Certainly, if the Society was to undertake all the “must-do's” and follow all the visions put forward, we would have made Microsoft Corporation seem like a cake-stall operation by now.

Quantification of lactoferrin in milk from New Zealand dairy goats - Hodgkinson AJ; Ross KM; Fahey SN; Prosser CG (Proceedings of the New Zealand Society of Animal Production, 2008)
Lactoferrin (Lf), an iron-binding protein, plays a key part in host defence with diverse protective roles in infection and inflammation, including allergy. It is present in most mucosal secretions, including colostrum and milk. To quantify the levels of Lf in milk from New Zealand dairy goats, a sandwich enzyme-linked immunosorbent assay (ELISA) was established. Purified Lf, extracted from goat colostrum, was used to raise antibodies in rabbits and for ELISA standards. The ELISA method involved coating goat Lf antibody onto microtitre plates then sequential addition of standard or test samples, biotinylated-goat Lf antibody and streptavidin-biotin conjugate, with a colorimetric endpoint employing 3,3`,5,5`-tetramethylbenzidine. The intra and inter assay coefficient of variation was 4.1% and 7.8%, respectively. Average recovery of added Lf was 104.5%. Cross reactivity with bovine Lf was 40% and negligible for other milk proteins tested. In goat milk samples collected over the lactation season, the average Lf concentration was 31.8 ± 7.3 (standard error of the mean); 33.4 ± 5.2 and 821.8 ± 269.4 mg/L, in early, mid- and late season, respectively. An ELISA method has been developed that accurately and reproducibly measures Lf in goat milk samples. Lf levels in New Zealand goat milk are similar to those reported for the cow.

Quantifying parasitic nematode larvae on pasture - Litherland AJ; Deighton DL (Proceedings of the New Zealand Society of Animal Production, 2008)
The aim of this study was to explore sources of paddock and laboratory variability in parasitic third stage larval (L3) tests. Recovery of Teladorsagia circumcincta larvae was greater than Trichostrongylus colubriformis larvae recovery from water (60 vs 43%; P <0.005), from water contaminated with soil (55 vs 36%; P <0.03) and from water with pasture (27 and 6%; P <0.001). Recoveries following seeding with either T. circumcincta or T. colubrifomis L3s onto pasture were similar (44% vs 56% respectively). Naturally contaminated pasture samples had similar mean larval number (larvae/kg DM) following extraction using either the plastic bag method (566) or Baermanns extraction (533). Pasture plucking to ground level 50, 100, 150 or 300 times had L3s 1,390 (range 406 - 3,846), 1250 (0 - 4,878), 360 (0 - 1,069) and 450 (182 - 742)/kg DM respectively (P

Relative economic value of wool processing parameters for New Zealand strong wool between 2003 and 2007 - Sumner RMW; McDermott AK; Cox NR (Proceedings of the New Zealand Society of Animal Production, 2008)
Price trends for a total of 147,416 lots of wool in the strong wool segment of the New Zealand clip sold at auction between 1 July 2003 and 30 June 2007 were analysed by multiple regression analysis to determine the effect on price of five key characteristics known to affect wool processing performance. Changes in exchange rate were allowed for by covariance against the exchange rate of the US dollar on the day of the auction. The residual standard deviation within the data set was 20.4 c/kg clean. Mean values of the slope of the regression, or relative economic value, were 0.4 ± 0.2 c/ kg clean/mm change in barbe length, -1.9 ± 0.9 c/kg clean/ìm change in mean fibre diameter, 2.5 ± 0.5 c/kg clean/CIE Y value change in brightness, -5.0 ± 0.6 c/kg clean/CIE Y-Z value change in intensity of yellowness and -16.8 ± 3.0 c/kg clean/% change in vegetable matter contamination. These estimated values align closely with values estimated in 1991 for the New Zealand clip as a whole confirming that despite the significant changes that have occurred within the wool processing industry the economic significance of individual wool characteristics to wool processors have not changed.

Reticulo-rumen growth and papillae development in farmed red calves from four to twelve weeks of age - Thompson BR; Hofstra G; Hammond KJ; Mackintosh CG; Hoskin SO; Littlejohn RP; Stevens DR (Proceedings of the New Zealand Society of Animal Production, 2008)
Ruminants are born with an underdeveloped forestomach (Warner et al., 1956) and as such operate as a monogastric animals until the reticulorumen (RR) and omasum have developed. The development of the rumen from birth to weaning has been well studied in dairy cattle (Heinrichs & Lesmeister, 2005), but not farmed red deer. Understanding pre-weaning rumen developmental processes is required for feeding programmes aiming to maximise pre-weaning growth rates of young red deer calves for early venison production. This preliminary study aimed to document the changes in rumen growth and papillae development ...Continued

A review of in-utero environmental effects on sheep production - Kenyon PR (Proceedings of the New Zealand Society of Animal Production, 2008)
There has been recent interest in potential intragenerational and intergenerational effects due to pre-natal programming and the implications these may have on production animals, such as the sheep. Evidence for intergenerational effects has been apparent for a significant period of time. The available data indicate that dam nutrition, age, parity, pregnancy rank, live weight, body condition, genotype and fetal genotype, and environmental conditions can all affect fetal development with potential post natal intra-generational consequences. However it is also clear that many of the observed effects in the fetus and young animal do not translate to productive effects in the adult although some models do exist. It is often difficult to compare studies due to differences in the; timing of the manipulation being investigated, live weight and condition of the dam, nutrition of the dam after the manipulation, and management of the young animal post birth. In the future it is probable that farmers will use this information to manipulate the dam in pregnancy to affect the productive performance of future generation(s). Currently few if any models of intergenerational effects exist. Further studies are required to identify consistent intragenerational and intergenerational models which affect productive performance in the adult and that identify the mechanisms responsible for the observed effects.

SNiP and cut: Quantifying the potential benefits of genomic selection tools for genetic fault elimination in sheep - Sise JA; Auvray B; Dodds KG; Amer PR (Proceedings of the New Zealand Society of Animal Production, 2008)
Whole genome single nucleotide polymorphism marker (SNP) technologies are rapidly being developed and could well play a role in the future selection of farmed animals. In sheep, work is being carried out to identify SNP`s associated with economically important production traits and disease resistance. Stud sheep breeders routinely cull up to 30% of lambs born due to a variety of faults. Despite this culling pressure, the faults keep occurring, suggesting low heritability, recessive inheritance or incomplete penetration of fault causing genes. The objective of this paper was to identify the potential of SNP fault detection and elimination in sheep. Simulation was used to predict changes in gene frequencies and in an index of genetic merit of production traits over time when between two and 30 SNPs were used to aid selection. The SNPs are assumed to predict the presence of deleterious recessive genes. As selection pressure applied to individual or combination SNPs increased, the rate of increase in production trait genetic merit slowed down. Thus, a balance would be required between the emphasis on SNPs actively used to select against genetic faults, relative to emphasis on genetic merit. This work identified scope for substantial economic benefits from application of SNP technology for removal of faults to both stud breeders and commercial sheep farmers.

Systems and economic analysis of use of maize silage within pasture-based beef production - Carracelas JG; Boom CJ; Litherland AJ; WMcG King; Williams ID (Proceedings of the New Zealand Society of Animal Production, 2008)
The productivity and profitability of the use of maize silage (MS) within pasture-based beef production systems was evaluated using the Farmax Pro® model. Farm systems were simulated based on an intensive one year-old steer production system with two pasture growth patterns (Waikato and Hawkes Bay), three different proportions of the farm in MS production (0%, 5% or 10%) and MS fed either during winter (W) or summer (S). MS cost 13.5 and 16.1 c/kg dry matter (DM) for Waikato and Hawkes Bay respectively. This price included the cost of growing, harvesting, ensiling and feeding. Beef schedule prices were based on $1.80/kg live weight (LW). Feeding MS increased beef production in all scenarios tested by a mean of 36% with values of 427, 581 and 576 kg net meat/ha/year for the no MS, S and W feeding systems respectively. Farm profitability (gross margin per hectare) was increased by feeding MS in W and S, with values of $934 and $754 respectively, compared with the no MS system of $636. MS feeding was still profitable at a schedule price of $1.40/kg LW and at higher MS costs up to 23 c/kg DM. Appropriate use of MS in beef production systems can substantially improve animal performance and farm profitability.

Testing for quantitative trait loci for lactation persistency in dairy cattle - Morris CA; Spelman RJ; Henderson HV; Cullen NG; Hyndman DL; Miller FM; Johnson DL; Molenaar AJ; Grigor MR; Davis SR (Proceedings of the New Zealand Society of Animal Production, 2008)
Lactational persistency has not been selected for in New Zealand dairy populations. Existing milk production data and pedigrees from New Zealand Holstein-Friesian cattle at pasture, recorded in the Livestock Improvement Corporation database were utilized with a grand-daughter design, for a genome-wide search for a quantitative trait locus for persistency of lactation. Persistency was defined as a weighted sum of test-day yields. A significant region was identified in one grandsire family on Chromosome 3 at microsatellite marker position AGLA247 (chromosomal position 67cM; P <0.05). To verify this result, data from a research dairy herd defining persistency as the mean of three weekly tests of daily yield in March (late lactation) divided by the equivalent daily yields in October (early lactation)) for three seasons beginning in 1997/98 were used in a phenotypic association study on Chromosome 3 only. One allele of marker HUJ246, close to the original region appeared to show an additive effect. The maximal difference between this genotype and the others at this marker locus was 12.3 ± 4.4% of the mean persistency. The potential use of this marker in the New Zealand dairy cattle population depends on the current allele frequencies in the industry.

Use of cDNA microarrays to investigate gene regulation in mastitis as a result of Escherichia coli infection in the bovine mammary gland - van Loenen-den-Breems NY; Molenaar AJ; Henderson HV; Seyfert H-M (Proceedings of the New Zealand Society of Animal Production, 2008)
Bovine mastitis is the result of an inflammatory event in the mammary gland usually caused by a variety of bacteria in the udder and is one of the three major causes of disease in the Dairy industry world wide. The cost of mastitis in New Zealand is estimated at NZ$180 million for the industry and (DairyInsight, 2006).

Variation in diet preference between sheep - Nicol AM; O'Connor RP; Williams SJ; Bryan SJ (Proceedings of the New Zealand Society of Animal Production, 2008)
Herbivores show preferences for some dietary components over others (Cosgrove & Edwards, 2007). The consequence of diet selection is that preferred components of the sward risk depletion and sustainability of sward composition is compromised. Species such as cattle that are less capable of discriminating between components of the sward (Grant et al., 1985) and maintain a higher intake on poorer quality swards (Collins & Nicol, 1986) are useful in combating the more selective grazing behaviour of sheep. ...Continued

A versatile sheep respiration chamber system for measurement of methane emission - Pinares-Patino CS; Lovejoy P; Hunt C; Martin R; Molano G; Waghorn GC; Clark H (Proceedings of the New Zealand Society of Animal Production, 2008)
Globally, the single most important source of greenhouse gas emissions from grazing systems is enteric methane (CH4) arising as a by-product of the fermentation of feed in the reticulo-rumen of ruminants (Clark et al., 2005). Methane is implicated in global warming and in countries where livestock constitutes a major emission source such as New Zealand, international commitments are driving research to develop emission reduction technologies, for which accurate measurements of CH4 emissions are ...Continued

Wool follicle characteristics in sheep with differing ventral wool length phenotypes - Craven AJ; Scobie DR; Ashby MG; Nixon AJ (Proceedings of the New Zealand Society of Animal Production, 2008)
Recent interest in sheep requiring less on-farm fleece management has lead to the development of sheep with long wool covering the trunk, but only short wool on the belly and breech. We have characterised developmental and structural features of the skin, including follicle density, primary to secondary follicle ratio and follicle activity state at various body sites of bare- and woolly-bellied ewes, and their foetuses. At 70 days of gestation, foetuses of bare-bellied ewes had developed fewer follicles than woolly-bellied sheep (1.7 ± 0.27 versus 2.8 ± 0.21 follicles per mm2; P<0.01). In adults, similar densities and ratios of primary to secondary follicles occurred in bare- and woolly-bellied ewes in each body site studied including dorsal, midside, anterior and posterior fleece positions, as well as the belly, breech and face. However, the proportion of inactive follicles in late autumn was greater in bare-belly adult ewes, not only on the belly (15.5 ± 1.9% versus 4.9 ± 2.9%; P<0.05), but also across the fleece which exhibited anterior-posterior and dorsal-ventral gradients in follicle activity. The short wool phenotype was thus associated with altered follicle cycles, but no differences in adult follicle densities. However, wool production might be compromised, as follicle activity varied across the whole fleece of bare-belly sheep.

Breed and heterosis effects for milk protein composition estimated in two stages of lactation in New Zealand dairy cows - Back PJ; Lopez-Villalobos N (Proceedings of the New Zealand Society of Animal Production, 2007)
The aim of this study was to estimate breed and heterosis effects for milk protein composition found within the two main breeds farmed in New Zealand, Holstein-Friesian (HF) and Jersey (J). Groups of 20 F, 20 J and 20 HFxJ crossbred cows (3 years and older) calved at pasture between July and September 2003 and were monitored throughout the 2003/04 season. Breed and heterosis effects were estimated for daily yields of milk, crude protein, true protein and casein and concentrations of crude protein, true protein, casein, α-casein, β-casein, κ-casein, α-lactalbumin and β-lactoglobulin, bovine serum albumin (BSA) and immunoglobulin G (IgG). Breed effects were significant (P<0.05) for all traits except for β-lactoglobulin, BSA and IgG. Compared to J cows, HF cows had significantly (P<0.05) higher daily yields of milk (+5.32 kg), crude protein (+0.13 kg), true protein (+0.11 kg) and casein (+0.10 kg) but significantly (P<0.05) lower concentrations of crude protein (-0.50 g/kg), true protein (-0.51 g/kg), casein (-0.45 g/kg), α-casein (-3.77 g/kg), β-casein (-2.08 g/kg), κ-casein (-1.74 g/kg) and α-lactalbumin (-0.14 g/kg). Estimates of heterosis effects for concentration of milk proteins were negative but only significant for κ-casein (-0.60 g/kg). These results show that that the individual protein fractions of milk are affected by breed but crossbreeding has no beneficial effect on milk protein composition.

Calcium balance in mid and late pregnancy and vaginal prolapse - Litherland AJ; Knight TW; Lambert MG; Cook TG; McDougal DBO; Day A (Proceedings of the New Zealand Society of Animal Production, 2007)
Given the hypothesis that Ca status may be implicated in bearings, the purpose of the research in experiment 1 was to observe Ca status in old twinewes in normal commercial conditions to determine whether an association exists, and in the second experiment to manipulate Ca status to determine its effects on the incidence of bearings. In experiment 1, Romney ewes, scanned as twin (n=12) or single (n=12) pregnant, on each of 7 farms were identified and sampled at approximately 60, 30 and 7 d before the onset of flock lambing. Whole flock bearing incidence was recorded. Eleven to 41% of pregnant ewes from different farms had marginal serum Ca and Mg concentrations at 60 and 30 d before onset of lambing. No relationship was found between serum minerals and metabolite concentration and bearing incidence among farms. The objective of experiment 2 was to reduce bearings on farms with high historical incidences of bearings by increasing Ca loss in urine in mid-pregnancy (60 to30 d pre-lambing) followed by increasing Ca supply in late-pregnancy (30 to 0 d pre-lambing). Five farmers fed 100 twin pregnant ewes 35 g of anionic salts in 300-500 g of supplemental pellets (DCAB -814 meq/kgDM) from 60 to 30 d before lambing. From 30 d these ewes were then injected with 4 ml of a long-acting vitamin D formulation (5 farms) while one farm also had an additional group supplemented with Ca (8g lime (ground calcium carbonate) /ewe) in an attempt to increase Ca availability. In addition, groups of ewes not treated withanionic salts were injected with vitamin D (2 farms) or supplemented with Ca (1 farm) from 30 d. Following consumption of anionic pellets in mid-pregnancy, the pH of the ewes’ urine was lower and urinary Ca:creatinine ratios were higher after 2 (6.73 vs. 7.32, P<0.002; 0.47 vs. 0.16, P<0.003) and 4 weeks (6.26 vs.7.23, P<0.001; 0.58 vs. 0.14, P<0.003) of treatment. However, neither the feeding of anionic salts in mid-pregnancy nor the Ca or vitamin D supplements in late-pregnancy consistently changed Ca serum concentrations or bearing incidence.

Cattle breed evaluation at the US Meat Animal Research Centre and implications for commercial beef farmers - Cundiff LV; Thallman RM; van Vleck LD; Bennett GL; Morris CA (Proceedings of the New Zealand Society of Animal Production, 2007)
Since 1969, 36 sire breeds have been evaluated for topcross performance in a series of experiments (Cycles) in the Germ Plasm Evaluation (GPE) Program. In Cycle VII, the 7 most prominent U.S. beef breeds (3 British breeds: Angus, Hereford, Red Angus; and 4 Continental European breeds: Simmental, Gelbvieh, Charolais, Limousin), comprising 83% of U.S. breed association registrations, are being evaluated. In the 1970’s, Continental breeds had greater growth rates and were heavier atweaning, yearling, and maturity. Today British breeds in the U.S. are comparable to Continental breeds for these traits. Steers of Continental sire breeds still excel in retail product yield (%), but those of British sire breeds excel in marbling, an important component of U.S. carcass value, and enjoy a slight (P<.05) advantage in tenderness over Continental breeds. Since 1973, current expected progeny differences (EPD) from breed associations and GPE data have been used to estimate breed differences annually. Since 1993 adjustment factors have been calculated to be added to the EPD of 16 breeds to calculate across-breed EPD for growth traits. Multi-breed genetic evaluations are being explored by scientists at three U.S. Universities (Cornell, Georgia, Colorado State). In Cycle VII, DNA was obtained on all sires, dams, and progeny produced in the F1 cross generation, grand progeny, and great-grand progeny to provide for parentage determination, and for identification and validation of quantitative trait loci (QTL). Alternative mating plans are being explored to include additional breeds (> 15), to provide more efficient estimates of direct and maternal breed and heterosis effects, and to facilitate use of QTL in multi-breed genetic evaluations. Our review describes how the U.S. beef cattle breeding industry continues to use the evolving GPE results, and how the Cycle VII DNA samples will be used to provide progressively more accurate predictors of sire EPD on a within-breed or between-breed basis, through groups such as the National Beef Cattle Evaluation Consortium. The opportunities for U.S. cattle breeders arising from new breeding technologiesare described, including the potential for similar opportunities to be used in the New Zealand beef industry.

Choice of the most appropriate models and estimation procedures of lactation curves for grazing dairy cattle - Bryant JR; Lopez-Villalobos N (Proceedings of the New Zealand Society of Animal Production, 2007)
The objective of this study was to determine the most appropriate lactation curve representation, a 4th order Legendre polynomial (LP) function or a mechanistic mammary gland (MG) model, for various lactation curve shapes of grazing cattle in New Zealand. The ability of two optimisation methods, evolutionary algorithm (EA) and the Newton method, used to find parameter values that minimised mean prediction error (MPE) was also determined. The 95% confidence intervals for the parameters values and goodness of fitness for each lactation function and numerical algorithm were obtained with a bootstrapping strategy. Milk yields of three different cows were chosen to describe bi-peak, highly variable, and springpeak lactation curves. The MG function was able to find the best fit between predicted and actual values for the bi-peak and highly variable lactation curves withMPE of 2.7 to 3.7%, compared with MPE of 6.5 to 11.9% for the LP function applying Newton and EA. For the traditional lactation curve, the LP function applying Newton had the lowest MPE (1.7%) with the MG function applying an EA the highest MPE (4.1%). Overall, minimal differences in MPE were observed when solving using the Newton and EA. However, the Newton method fixed some parameters values of the MG function to achieve approximately the same MPE as the EA which manipulated all parameter values. The results of this study illustrate that a MG function solved with an EA is an accurate and efficient way to model non-standard lactation curves but a LP function in combination with the Newton method canbe better option for more standard lactation curves

A comparison of carcass characteristics and meat quality for Angus, Hereford x Friesian, and Jersey x Friesian steers - Purchas RW; Morris ST (Proceedings of the New Zealand Society of Animal Production, 2007)
The aims of the two trials described here were to compare carcass characteristics and meat quality of Jersey-Friesian cross steers (Je x Fr) with Hereford-Friesian cross steers (He x Fr) and purebred Angus steers. Trial 1, which compared rising 3-year-old He x Fr with Je x Fr steers (20/grp), showed that the Je x Fr group had lighter carcass weights (93%; P<0.001), yellower fat, slightly lower weight-adjusted dressing-out percentages (P<0.01), heavier weight-adjusted livers (P<0.01), and longer carcasses at the same weight (P<0.001). In Trial 2, 27-month Je x Fr steers (n=15) were compared with He x Fr (n=15) and Angus steers (n=14). Differences similar to those for Trial 1 were shown, and in addition the Je x Fr steers had lower fat depths and a lower yield of several cuts from the round.For both trials the Je x Fr group had a more mature pattern of incisor teeth eruption. For Trial 2 the quality of meat from the longissimus muscle did not differ between groups for ultimate pH, intramuscular fat level, colour, Warner-Bratzler shear force, or waterholding capacity. Sensory analysis by a trained panel revealed no differences in tenderness, flavour, or juiciness, in contrast to some other reports where beef from Jersey or Jersey-cross cattle has been favoured. These results indicate that the Je x Fr steers in these trials offered no advantages relative to He x Fr or Angus cattle, but they did show some minor disadvantages. These results, however, need to be considered alongside other reports indicating that Jersey or Jersey-cross steers will sometimes yield beef with advantages in levels of marbling fat and palatability.

Comparison of suckling frequency of red and F1 wapiti-red calves reared on red hinds - Ward JF; Archer JA; O'Neill KT; Littlejohn RP (Proceedings of the New Zealand Society of Animal Production, 2007)
In New Zealand venison production systems crossbreeding red hinds with wapiti stags is very common. The resultant wapiti-red crossbred offspring is a larger, fastergrowing animal than its red counterpart. How do these crossbred progeny grow faster on a red hind? We hypothesised that the crossbred progeny would have increased milk intakes, which would be reflected in increased suckling of their red hind dams. A pasture based lactation experiment was conducted over the 'natural' (non-weaned) suckling period (birth Nov/Dec. to Sep.) with F1 wapiti-red crossbred single and twin calves (n=11) naturally reared by red hinds (n=9), and red calves (n=8) naturally reared by red hinds (n=8). Suckling behaviour was observed at least one day per month between dawn and dusk. Suckling bout frequency, duration and time of day were recorded for all calves and any allosuckling was also noted. We found no significant differences (p >0.05) in suckling bout time, frequency or total time spent suckling between red or wapiti crossbred offspring. The only confirmed allosuckling was between individuals from different sets of twins. The F1 wapiti-red crossbred offspring were 30% heavier, with growth rates up to 39% greater than their red cohorts. These results have interesting implications for the red hind crossbred calf venison production system; do the wapitired crossbred calves consume more milk? If so how do they influence the hind’s milk production? Do they consume more pasture and/or substitute it for milk? Better understanding of these factors should help increase calf growth rates during lactation.

Comparison of the effect of simultaneous grazing of sheep or cattle with hinds during fawning - Nicol AM; Edwards GR; Ridgway MJ; Griffiths WM (Proceedings of the New Zealand Society of Animal Production, 2007)
Groups (4) of aged, pregnant red deer hinds (n = 7 or 12) were set-stocked pre-fawning with similar liveweight per ha of either dry ewes or yearling heifers in one of two paddocks equally divided in area (2 replicates). Cattle and sheep were progressively withdrawn from each area independently so that the average pasture height did not fall below 6 cm. The liveweight of the hinds and fawns was recorded and pasture samples taken for botanical and chemical analysis. There was no significant effect of sheep vs. cattle on the liveweight change of hinds or their fawns. All groups of hinds lost condition over lactation even though pasture height was maintained around 6-8 cm. However the liveweight gain of the fawns (from mid January to early March) was close to 350 g/day. Overall, there was no significant difference in composition or quality between the pastures grazed by the two stock combinations. We conclude from this study that under the conditions of this trial, in which the pasture was kept under tight control (6-8 cm) over the whole of lactation, there was no difference in the effect of the co-grazing species (sheep or cattle) on the performance of lactating hinds and their fawns.

Comparison of white clover , perennial ryegrass and the high tannin containing forage Lotus pedunculatus as finishing diets : Effect on sheepmeat quality - Farouk MM; Tavendale M; Lane G; Pulford D; Waller J (Proceedings of the New Zealand Society of Animal Production, 2007)
Rams were finished for 22 days on Lotus pedunculatus(LP), perennial ryegrass (Lolium perenne) (RG), or white clover (Trifolium repens) (WC). WC sheep had higher carcass weight (P < 0.001), muscle fat (P < 0.01) and back fat (P < 0.03) depths compared to those finished on LP or RG. Muscle glycogen at slaughter was lower (P < 0.01) in RG compared to LP and WC. Loin p-Cresol was higher (P < 0.001) in LP animals compared to WC or RG. Meat from RG tended to havea more stable retail colour display life compared to LP or WC (P < 0.01). Meat from LP had higher loss of weight during cooking (P < 0.05) compared to WC. The animal diet did not affect the flavour of their meat. There was a strong negative correlation between loin p-Cresol and sheepy odour (r = -0.7; P < 0.05). Within the parameters of this study, finishing lambs on a high tannin containing forage diet did not improve the quality attributes of their meat. The digestibility of the forage diet seems to have exerted a stronger effect on meat quality.

Concentrations of pesticides in fleeces after pour-on and saturation dipping of Merino sheep - Rankin DA; Reid TC; Cole DJW; Urquhart RA; Syhre MS (Proceedings of the New Zealand Society of Animal Production, 2007)
A year-long farm trial was performed in 2003/04 to determine the relative efficacies of commercial formulations of diflubenzuron and triflumuron lousicides and measure pesticide concentrations in different parts of the fleece throughout the year. Significant differences were found between the concentrations of pesticides present on samples of fleeces taken from the back and side initially (P<0.05), 5 months (P<0.001), and 12 months (P<0.05) after pour-on treatments. The bulk of the pesticides from pour-on treatments remained in the zone where they had been applied and little moved to the sides of the sheep. Five months after application pesticide concentrations were significantly higher (P<0.001) in staple tip compared with butt samples on both back and side fleece samples for pour-on or jetting treatments, confirming recent predictions that diffusion of pesticides in greasy wool will be limited. Concentrations in butt samples from 5 months onwards were near or less than the mean LD95 doses reported for diflubenzuron for susceptible – 0.31 mg/kg, 95% confidence limits (CL) 0.16-1.25 mg/kg – and resistant lice populations – 4.4 mg/kg, 95% CL 1.4-71 mg/kg. The results offer a possible explanation for the anecdotal reports of poor efficacy of some pour-on louse treatments and treatment failures on farm.

Culture of ovine keratinocytes : An experimental model for wool growth - Rufaut NW; Goldthorpe NT; Craven AJ; Wallace OAM; Wildermoth JE; Pedersen G; Nixon AJ (Proceedings of the New Zealand Society of Animal Production, 2007)
Wool fibres are formed from the germinative epithelium, a population of keratinocytes at the base of wool follicles. In order to test the function of candidatewool growth genes and pharmaceuticals, we have developed methods to isolate and maintain these cells inculture. Pure, clonal lines of ovine keratinocytes were isolated from both vibrissae and wool follicles. Vibrissa-derived cells proliferated more extensively before senescing, but cells from both follicle types possessed ample proliferative potential for further experimentation. Standard assays have been established to quantify keratinocyte proliferation and apoptosis in culture. Differentiation of keratinocytes could be induced by maintaining them at high density for a week. Keratinocytes expressed differentiation markers for epidermis and inner root sheath. Expression of a chosen gene could be up-regulated by transfection with a liposome-borne plasmid. A transfected plasmid encoding a fluorescent reporter protein was expressed in 68-100% of cells. Similarly, expression of a gene of interest could be suppressed by RNA interference. The experimental tractability of these keratinocytes suggests that they will be a valuable model for investigating the cell biology and molecular genetics of wool growth. The methods described form a unique experimental system to identify leads for new technologies that improve wool production.

Current status and future of genomic selection - McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2007)
DNA marker test usage is expanding rapidly in the New Zealand livestockindustry. Uptake is already reaching in excess of 30% of animals in the sire breeding tier for some industries. However, what is confusing to many commercial farmers and advisors is the diversity of claims and uses of these tests and the jargon that surrounds the topic. The aims of the associated Landcorp Speaker presentation and this contract, are to clarify just what DNA markers can do, what work is currently being undertaken, what tests are currently available, and what implications these have for farming systems in New Zealand over the next decade.

Current status of QTL and association studies in New Zealand cattle , sheep and deer - Morris CA; Campbell AW; Cullen NG; Davis GH; Everett-Hincks JM; Hall RJ; Henry HM; PL Johnson; McEwan JC; Phua SH; Wilson T (Proceedings of the New Zealand Society of Animal Production, 2007)
In the last 15 years, a series of experiments has beencarried out to search for quantitative trait loci (QTL) in New Zealand cattle, sheepand deer. A QTL represents the position on a chromosome where there is a statistically significant genetic effecton a measured trait. This paper reviews data published so far from these QTL trials and from various association studies. Although the measurement of traits (or ‘phenotypes’) and the sampling of tissue or fluid for DNA may be complete, the genotyping of DNA isstill incomplete in most studies; further work may be expected as new DNA genotyping techniques and new genomic data become available, and as funds allow. In cattle, we describe the current status of research for carcass composition, meat quality, pubertal traits, milk yield and milk composition traits, and resistance to facial eczema and bloat. In sheep, we include QTL searches for disease traits (resistance to nematode parasites, facial eczema, ryegrass staggers, and footrot), muscling and carcass composition, reproductive traits, wool traits, and lamb survival. In deer, QTL searches have been carried out for live weights, seasonality and pubertal traits, using measurements from an interspecific hybrid. Generally, significant results have been followed further by finemapping and independent validation, before release to industry. Some of the mapping techniques will be described, with examples. So far, QTLs under study in New Zealand have led to the identification and use of gene-tests or marker-tests for meat tenderness and carcass composition in beef cattle, milk yield and composition traits in dairy cattle, and meat yield %, muscling and litter size genes in sheep.

The deer industry's productivity strategy : A five-year vision - Pearse AJ; Fung L (Proceedings of the New Zealand Society of Animal Production, 2007)
Advances in deer farming productivity have been muted in relation to other livestock industries but the potential for dramatic improvement clearly exists. Anindustry working group has developed a productivity strategy closely aligned with the venison industry strategy that emphasises extending the four-month consumption demand of the traditional game seasonto a 12-month chilled supply of high-value retail product. Underpinning this, the productivity strategy targets two basic outcomes; more calves conceived, born earlier and surviving to sale, and heavier prime animals supplied earlier in the season. Productivity targets include a 2% annual increase in survival to sale over the next five years and a 2.5% annual individual growth rate increase. Emphasis is on capturing genotype advantages in growth and seasonality, and determining aspects of seasonal nutrition and the potential of new forage cultivars to add to this potential for growth. Productivity success must be measured in economic indices (carcase returns per hectare, cost of production per kilogram of dry matter consumed and per hectare economic performance) and the planned timing of carcase harvest against a variable seasonal schedule. Productivity improvements are best illustrated in clear practical situations providedby focus farms to inspire technology uplift and practical feedback from farmers and researchers.

Developing genomic resources for whole genome selection - McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2007)
After more than 20 years of research, genomic technology is now on the cusp of widespread adoption in animal industries. Industry adoption will initially involve improvement of existing breeding and traceability systems. DNA variants, commonly called markers, used in these systems can provide 4 pieces of information: identity, parentage, prediction of an animals genetic worth and its individual performance. The usability of the technology and its adoption is increasing as genotyping prices decline. The major challenges are: to decrease sample collection, processing and reporting costs, and integrate the systems so that all 4 separate pieces of information can be obtained from a single test. Underpinning future research will be availability of sequenced genomes for each of the production species, and large scale “SNP chips” derived from them. Currently, the technology provides the ability to identify and map and use variants affecting animal performance in commercial populations. These technologies use existing natural genetic variation already present in the population. The potential of these technologies is safer and more nutritious food produced with less environmental impact and greater animal welfare due to lower level of disease.

Development of large scale commercial AI for genetic improvement in farmed red deer in New Zealand - McMillan WH; Asher GW (Proceedings of the New Zealand Society of Animal Production, 2007)
Experienced bovine AB technicians can be readily trained to successfully perform trans-cervical AI in red deer. Stags of all ages, including yearling spikers, can produce semen of acceptable quality and quantity at regular intervals from as early as February until mid-winter. Pregnancies rates to a single fixed-time insemination are typically 60-75% with unknown herd factors contributing much of the variation. Yearling hinds are capable of acceptable pregnancy rates when inseminated in late February, at least a month earlier than is current practice. Within broad limits, considerable flexibility appears to exist when hinds are inseminated relative to the end of synchrony treatment.A deer-specific intra-vaginal progesterone-releasing device has been shown to provide higher terminal levelsof circulating progesterone compared with existing devices. Current field trials will determine its affect onpregnancy rates. We conclude that the genetic and reproductive technologies for increasing weight-for-age in deer have been successfully integrated and applied to commercial red deer in New Zealand.

Does high-frequency immobilisation of sheep post-mortem affect meat quality ? - Toohey ES; Hopkins DL (Proceedings of the New Zealand Society of Animal Production, 2007)
This study evaluated the impact of a newly developed high frequency immobilisation unit on meat quality traits of lamb carcases. This was achieved by examining pH and temperature profiles, objective meat colour (L*, a*, b*, ratio values 630 nm/580 nm and chroma), shear force, cooking loss and sarcomere length. In total 80 lambs from 3 different consignments were assessed. The animals were killed over two days and of the 40 killed on each kill day, 20 were exposed to the immobiliser and 20 were not. The results showed that the high frequency immobiliser unit had no effect on sarcomere length and pH except when pH was predicted at 25°C. There was also no effect on shear force and cooking loss percentage, but there were some minimal differences for some meat colour traits. These differences were shown in the final GM (rump) measurements only (7 day aged), where cuts from immobilised carcases had a lower L* values and higher a*, b* and chroma values. Overall the results showed that there were minimal effects of the immobilisation treatment which confirms previous anecdotal evidence. The high frequency immobilisation unit has benefits in that it enables abattoir workers to begin processing the carcases safely within approximately 30 seconds of death with no apparent negative effect on meat quality traits. It also means that other electrical inputs can be used to manipulate pH fall, without immobilisation affecting pH.

A dynamic model incorporating dietary protein for predicting liveweight gain of parasitised grazing lambs - Louie K; Burggraaf VT; Pacheco D (Proceedings of the New Zealand Society of Animal Production, 2007)
Internal parasites are one of the major constraints toliveweight gain (LWG) in young grazing ruminants. However, even in parasite-free animals, diets low in crude protein can constrain LWG from values expected on the basis of metabolisable energy intake alone. We investigate the impact of protein supplementation in overcoming reduced growth rates of parasitised animals. This was done via a dynamic model which assumes increased maintenance requirements (immune requirements, increased cell turnover and mucous production) in parasitised animals. A key output from the model is LWG over an extended grazing period. We calibrated and validated the model using published data from an indoor feeding experiment in which trickle-infected lambs were fed for 20 weeks on three diets providing different amounts of metabolisable protein. The mean liveweight and worm burden predicted from the model compared well with experimental data. Such models will prove useful in designing supplementation strategies for grazing lambs where anthelmintic control of parasites is not a management option.

Effect of age on methane emissions of red deer stags from weaning until one year of age grazing perennial ryegrass-based pasture : Brief Communication - Swainson NM; Hoskin SO; Clark H; Lopez-Villalobos N (Proceedings of the New Zealand Society of Animal Production, 2007)
The emission of greenhouse gases is a current global issue as global warming and climate change appear a reality. The Kyoto Protocol is an international agreement, which New Zealand (NZ) has signed and under obligations of the agreement, New Zealand must reduce its greenhouse gases (GHG) to the emission levels of the baseline year (1990), by the first ratification of the Protocol in 2008. Methane emissions from ruminant livestock in NZ represent 31.3% of New Zealand’s total greenhouse gas emissions; therefore accurate inventories of methane production for all farmed livestock classes are required.

Effect of divergent selection for wool bulk on live weight and wool characteristics in Perendale sheep - Sumner RMW; Clarke JN; Cullen NG (Proceedings of the New Zealand Society of Animal Production, 2007)
A sixteen year selection trial in a flock of Perendale sheep selected for either increased (H line) or decreased (L line) wool bulk at yearling (hogget) shearing, was undertaken at Whatawhata, and later Winchmore Research Stations. A total of 2,620 progeny sired by 172 rams joined in single sire matings were measured, with data from an additional 664 fleeces providing direct information on base flock characteristics. A restricted maximum likelihood (REML) animal model adjusting for fixed effects of year, sex, birth date and birth/weaning rank was fitted to the data. Heritability estimates ± standard errors for each of the measured characteristics were; core wool bulk (0.57 ± 0.03), pre-shear live weight (0.35 ± 0.04), greasy fleece weight (0.44 ± 0.04), washing yield (0.42 ± 0.03), clean fleece weight (0.45 ± 0.03), staple length (0.54 ± 0.03), total crimps (0.38 ± 0.03), crimp frequency (0.46 ± 0.03), mean fibre diameter (0.62 ± 0.04), fibre diameter variation (0.58 ± 0.04) and mean fibre curvature (0.67 ± 0.04). At the end of the trial, line divergence (H – L) in core wool bulk and fibre curvature amounted to 2.5 phenotypic standard deviation units. It was associated with a positive divergence in crimp frequency and a negative divergence in staple length, washing yield and clean fleece weight of +2.1, -1.7, -1.4 and –0.8 standard deviation units respectively, and lesser changes in other traits.

The effect of Finnish Landrace and Texel ewe and lamb behaviour after tagging on lamb survival to weaning - Everett-Hincks JM; Blair HT; Stafford KJ; Lopez-Villalobos N (Proceedings of the New Zealand Society of Animal Production, 2007)
The study was carried out on a commercial New Zealand sheep farm with performance recorded straightbred Finnish Landrace and Texel primiparous ewes. The objective of the study was to determine the strength of ewe-lamb attachment at tagging by investigating the behaviour of Finn and Texel ewes and their lambs and relate those behaviours to survival to weaning. Lamb and ewe behaviour was observed for ten minutes after the lambs were ear tagged. Finn ewes took at least twice as long to contact their lambs than Texel ewes (P<0.01). There were no breed differences for time of lamb to stand and suck after tagging. Finn twin lambs took longer to follow their dam than Texel twin lambs (P<0.01). Ewes with higher Maternal Behaviour Score (high MBS favourable) contact their lambs quicker and the lamb stood, sucked and followed its moving dam more quickly than lambs of ewes with low MBS (P<0.05). Texel ewes with twins had higher low-pitch bleating frequencies than Texel ewes with a single lamb (P<0.01). MBS had a significant and positive effect on low-pitch bleating frequency (β=19.3 ± 3.51 bleats/MBS, P<0.0001). Ewes with lower MBS at tagging high-pitch bleated significantly more if their lamb took longer to stand (β=5.25 ± 0.65 bleats/minute, P<0.0001). Lamb survival improved3-fold for lambs that sucked their dam (P<0.01) and improved nearly 5-fold for lambs that stand, within ten minutes after tagging (P<0.05). Lamb behaviour at tagging better explained the variation in lamb survival than the ewe behaviours analysed.

Effect of increased somatic cell count on lactation yields of milk , fat and protein - Winkelman AM; Montgomerie WA; Johnson DL (Proceedings of the New Zealand Society of Animal Production, 2007)
The purpose of this study was to estimate the effect of increased SCC on production in New Zealand dairy farms. Herd test data from lactations one through six were used in the study. Herd test milk, fat and protein yields were modelled as a function of days in milk at the time of the herd test and the logarithm (base 2) of SCC. The model estimates were used to obtain the predicted value for each observation using the actual log SCC and again where the log SCC was increased by one (i.e. doubling the SCC level). For first-lactation cows, the reduction in a 270-day lactation yield from a doubling of the SCC was estimated to be 78 litres, 2.39 kilograms and 2.04 kilograms for milk, fat and protein yield, respectively. Herd SCC level also influenced the extent to which a doubling of SCC decreased production. For first-lactation cows every doubling of SCC was predicted to result in an average loss of 67 and 90 litres in the lowest and highest quartiles, respectively.

The effect of live yeast inclusion into mixed forage diets on milk yield , locomotion score , lameness and sole bruising in first lactation Holstein Friesian dairy cattle - Lethbridge LA; Margerison JK; Parfitt D (Proceedings of the New Zealand Society of Animal Production, 2007)
The aim was to assess the effect of supplementing mixed forage diets with live yeast on milk yield, locomotion score, lameness and sole bruising in first lactation Holstein Friesian dairy cattle. Heifers (n 34) were divided into two groups according to calving date, breeding value (milk fat and protein yield), live weight, body condition and post-partummilk yield and offered a mixed forage diet of grass, maize and whole crop silage, 17 were offered the mixed diet withthe addition of live yeast (Y), 17 were offered the same mixed forage diet with no additional live yeast (NY). All animals were assessed weekly for milk yield and composition, locomotion score up until 160 days in milk (DIM). Mean milk yield (Y: 29.5, NY: 27.1) and milk solids (Y: 1.98, NY: 1.80 (kg/h/d) were significantly higher with the addition of yeast (P<0.001). Sole lesion score increased significantly at day 160 (50 DIM: 1241 b, 100 DIM: 1295 b, 150 DIM: 1676 a) and of the WL at day 100 pp (50 DIM: 1042 b, 100 DIM: 1448 a, 150 DIM: 1710 a) (P<0.001). The hind outer (HO) claws had significantly higher lesion scoresthan inner claws (sole outer: 340.2, others 149.4 to 184.2; White line Outer: 267.5, others: 168.4 to 228.9) (P<0.001). Heifers offered forage diets with the addition of yeast had significantly lower sole (Y: 1151.5 b, NY: 1645.3 a)(P<0.05) and WL lesions at 160 DIM. The addition of live yeast increased milk yield and reduced lesion and locomotion score in first lactation heifers.

The effect of maternal liveweight gain of 15-month-old beef heifers on foetal weight - Hickson RE; Lopez-Villalobos N; Kenyon PR; Morris ST (Proceedings of the New Zealand Society of Animal Production, 2007)
Dystocia in 2-year-old beef heifers is a major factor limiting the willingness of farmers to breed 15-month-old heifers in New Zealand. Foetal oversize relative to the size of the heifer is a contributor to dystocia. This study aimed to determine the effect on foetal weight of maternal liveweight change during joining and early pregnancy. Sixteen 15-month-old Angus heifers were allocated to moderate (444 ± 30 g/day) or low (109 ± 28 g/day) liveweight-gain treatments for 21 days prior to and 91 days after insemination. Gravid uteri were recovered on day 91 of pregnancy. Foetuses from the low-fed heifers tended to be heavier than foetuses from the moderate-fed heifers (215.6 ± 6.7 g and 198.4 ± 6.8 g, respectively; P=0.09). Foetal weight per 100 kg maternal weight was greater (P<0.01) in foetuses from the low treatment (58.9 ± 2.5 g/100 kg) than in foetuses from the moderate treatment (47.4 ± 2.6 g/100 kg). Weight of foetal membranes was greater (P<0.05) in the low treatment (262 ± 16 g) than the moderate treatment (213 ± 16 g). Foetal weight was correlated with cotyledon weight (r=0.59; P<0.05). Moderate compared with low maternal liveweight gain reduced foetal weight relative to maternal live weight.

Effects of dietary herb supplements on sheepmeat flavour - Fraser K; Lane GA; Kirk MR; Keogh RG; Cummings TL (Proceedings of the New Zealand Society of Animal Production, 2007)
Sheepmeat flavour is characterised by distinctive species derived odours and flavour notes derived from the diet termed as ‘pastoral’ for pasture-based farming systems. An exploratory investigation was undertaken to determine if the flavour attributesof sheepmeat could be altered by short-term dosing of sheep with fresh or concentrated herbs. Twelve animals were dosed with 9 different fresh and/or concentrated herbs over 3 days. The animals were slaughtered, sub-sampled, and chemical analyses of levels of flavour compounds in the subcutaneous fat were performed along with sensory evaluation of the meat samples by a trained panel. From the sensory evaluation of the meat samples, the two animals that received the garlic powder supplement were described by the panellists as ‘garlic’,and these samples were significantly less intense in ‘sheepmeat’ (P=0.001) and ‘sweet’ (P=0.007) flavours and also had increased ‘barnyard’ (P=0.011) and ‘foreign’ (P<0.001) flavours. Subcutaneous fat skatole and indole levels for these animals were found to be significantly higher (P<0.001) compared to those grazingryegrass. Other treatments were not significantly different in sensory evaluation. A garlic powder dose response trial was then carried out with 5 sheep receiving between 0 and 200 g/day of powder for two days. After slaughter, subcutaneous fat skatole levels were found to be elevated for animals receiving >50 g/day garlic powder. The results indicate that dosing sheep with garlic powder has a detrimental effect on the animal’s ability to detoxify and remove skatole from the circulatory system, with consequent detrimental effects on the overall sensory quality of the meat. Thus a herbal dietary supplement to either mask undesirable flavours of sheep meat, or impart desirable flavours, is yet to be discovered.

The effects of ewe size and nutrition during pregnancy on growth and onset of puberty in female progeny - van der Linden DS; Kenyon PR; Jenkinson CMC; Peterson SW; Lopez-Villalobos N; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2007)
In 2005, ‘heavy’ and ‘light’ Romney ewes were selected, synchronized and artificially inseminated. Half of the ewes in each weight group were fed ad libitumand the other half were restricted to maintenance from days 21-140 of pregnancy, resulting in fourgroups: ‘heavy’-maintenance (HM), ‘heavy’-ad libitum(HA), ‘light’-maintenance (LM) and ‘light’-ad libitum(LA). The aim of the present study was to investigate the effects of ewe size and nutrition during pregnancy on growth and onset of puberty in female progeny. Lamb birth weights were recorded. After weaning, the progeny were managed as one flock and weighed monthly. Crayon-harnessed teaser rams were joined with the lambs to investigate the onset of puberty. Maternal nutrition during pregnancy affected live weight of lambs from 22 days of age till weaning (100 days of age) (P<0.05). During the first 22 days of life, the growth rate of lambs born to LM was lower (P<0.05) compared with the other groups (215 ± 8.2, 261 ± 8.0, 250 ± 7.9, 275 ± 7.3 grams/day, for lambs born to LM, LA, HM and HA ewes respectively). From weaning until one year of age lambs born to LM dams were lighter than lambs born to HM dams (P<0.05). No differences in the age of onset of puberty were found among the four groups. Singletons reached puberty earlier than twins (P<0.01). At 13 months of age, no long-term effect of maternal nutrition on the live weight of resulting ewe offspring was found, although dam size had a significant effect on live weight and growth rate. However, neither dam nutrition nor size had any effect on the age of onset of puberty.

Effects of experimentally induced and treated Streptococcus uberis mastitis early in the dry period on production in the subsequent lactation - Petrovski KR; Williamson NB; Fernandez C; Grinberg A; Lopez-Villalobos N; Parkinson TJ (Proceedings of the New Zealand Society of Animal Production, 2007)
The effect of experimentally induced clinical mastitis in the early dry period (EDPCM) upon the milk production in the subsequent lactation was examined. Animals with low somatic cell counts at herd test (n=165) were experimentally exposed to Streptococcus uberis in their early dry period in an efficacy study of two external teat sealants. Animals that developed EDPCM after challenge (n=127) were treated with an antibiotic after observation of clinical mastitis. Total lactation yields of milk, fat, protein and milk solids were analysed with respect to treatment group (fixed effect) and the covariables: calving week (linear), parity (linear and quadratic) and proportion of Holstein-Friesian genes (linear). For animals that suffered EDPCM and those that did not, there was no difference in production (milk yield; 5126 vs. 5010 litres, fat yield; 267 vs. 264 kg, protein yield; 182 vs. 179 kg). It was concluded that promptly treated EDPCM due to S uberis, did not affect production in the subsequent lactation.

The effects of zeranol or zinc supplementation before lambing on the incidence of vaginal prolapse in twinning ewes - Litherland AJ; Knight TW; McDougall DBO; Cook TG; Sprosen J; Lambert MG (Proceedings of the New Zealand Society of Animal Production, 2007)
The objectives were to determine whether Zeranol (ZER) and its metabolites or pharmacological zinc levels could change the incidence of vaginal prolapse(bearings) in ewes. In the ZER experiment 100 twin pregnant ewes were controls, a further 50 ewes each received either two low (24 mg and then 12 mg) or two high (36 mg and then 24 mg) doses of zeranol (ZER) implants separated by a four-week interval with 65% of treated ewes receiving an additional 12 mg implant at set stocking. Urine samples were collected from 12 ewes, twice weekly, bulked into three samples and analysed for Zearalenone (ZEN), ZER and creatinine. Two weeks after receiving an implant, the ZER:creatinine ratio increased from 2.6 in C ewes to 21, 30 and 36 and the ZEN ratio from 3.25 to 6.7, 10.8 and 14.7 following treatment with 12, 24 and 36 mg of ZER (P<0.01). One month after treatment the ZER and ZEN ratios had decreased but were still higher in treated than control ewes (ZER 3.6 vs.11, P<0.01; ZEN 1.2 vs.5.2, P<0.01). The bearing incidence was 3%, 2% and 2% for control, low and high dose ZER respectively. In the second experiment 100 scanned twin or triplet pregnant ewes were administered with 72 g of zinc oxide (The Time Capsule ®) as a ruminal bolus 4-6 weeks before lambing on four farms with historical high incidences of bearings. Pre-treatment and all control serum zinc concentrations were low (9.4 ±0.2 mmol/L) but not considered deficient. Zinc supplementation increased serum zinc concentrations to 21.5 mmol/L (P<0.001). Bearing incidence was higher (P<0.001) in zinc-treated (4%) than in control ewes (1.9%). In conclusion, bearings are not caused by ingestion of ZEN in late pregnancy. The role of zinc in bearings warrants further study.

Estimation of autumn live weight breeding values in progeny test datasets when progeny are slaughtered to achieve a target carcass weight - Jopson NB; McEwan JC; Knowler KJ; Wheeler R (Proceedings of the New Zealand Society of Animal Production, 2007)
An analysis was undertaken to investigate how lamb autumn live weight breeding values could be calculated from fixed carcass weight progeny tests (e.g. lambs slaughtered at monthly intervals at a threshold carcass weight). Analysis of growth rate is problematic for this progeny test design as the slaughter groups may experience vastly different environmental conditions, both within and between years. Variance components were estimated from an animal model using restricted maximum likelihood (REML) on data from 11,411 Coopworth progeny records and 126 Coopworth sires. The dataset contained records of weaning weight and live weight at four, five and six months of age (LW4, LW5 and LW6, respectively) collected from 1995 to 2004 in a flock run at Woodlands Research Station. The multivariate mixed linear model included lamb birth day deviation as a covariate, sex of lamb, birth rearing rank, age of dam and live weight contemporary group as fixed effects, and sire as a random effect. The WWT model also had dam fitted as a random effect to give WWT direct and maternal effects (WWTdand WWTm). The analysis was then repeated, but with animals records removed from the dataset once they achieved a threshold weight of 31 and 27kg for ram and ewe lambs, respectively, on data prior to or following linear scaling by contemporary group mean. The heritabilities estimated from the full dataset for WWTd, WWTm, LW4, LW5 and LW6 were 0.30±0.03, 0.04±0.01, 0.49±0.02, 0.49±0.02 and 0.51±0.02, respectively. These traits were highly correlated with both phenotypic and genetic correlations between the direct traits ranging from 84 to 99%. The same analysis on the two culled datasets resulted in only minor changes the variance components. The correlation between sire breeding values for autumn live weight (LW6) estimated from the full and the two culled datasets were 98.8% for both models. Autumn live weightbreeding values can be accurately estimated from datasets which include progressive culling if a multivariate live weight analysis is undertaken, and data from all animals measured at each date are used.

Evaluation of a model that estimates insulin sensitivity in dairy cows - Back PJ; Boston RC; Palliser CC; Kolver ES; Chagas LM (Proceedings of the New Zealand Society of Animal Production, 2007)
Glucose challenge data was used to model parametersdescribing the dynamics of the glucose-insulin system such as glucose effectiveness (SG), acute insulin response to glucose (AIRg) and insulin sensitivity (SI) in dairy cows. The relationship of these parameterswith post-partum anovulatory interval (PPAI) was also determined. Twenty-five HF cows of New Zealand (NZ; n=13) and Overseas (OS; n=12) origin, were fed either pasture (n=12) or a total mixed ration (TMR; n=13) in a 2x2 factorial design. At two weeks postpartum, they were challenged intravenously with 300 mg of glucose/kg live weight. There was no effect of diet on SG(P=0.302), SI(P=0.17) or AIRg(P=0.093) despite TMR cows of both genotypes having higher values. There was no effect of genotype on SG(P=0.234), SI(P=0.742) or AIRg(P=0.385). Correlations of these parameters with PPAI were not statistically significant: SI (r 2=0.087, P=0.310), SG(r 2 = 0.001, P=0.962) and AIRg(r 2 =0.036, P=0.320). Use of this model demonstrated that insulin response parameters were not closely associated with PPAI.

Evaluation of a practical weaning weight index for extensively-grazed beef cows - Thomas CW; Bywater AC; Miller SP (Proceedings of the New Zealand Society of Animal Production, 2007)
Little objective culling is practiced in many commercial beef herds in New Zealand possibly due to the absence of a performance recording system that is able to accurately predict the calf rearing ability of cows when calving date is unknown. Data of 1,306 calves from four different herds including birth, marking and weaning weights and dates was used to construct an Extensively Grazed Weaning Index (ECWIndex) to rank cows on their calf rearing ability without the use ofcalving date. Three indicator traits, marking weight, weaning weight and average daily gain (ADG) between marking and weaning (all adjusted for sex of calf and age of dam but not for age of calf) were used in the index as they were the most favourably correlated with 200 day weight of the readily measurable calf traits considered. A number ofeasily obtainable herd variables were used to calculate index weights for the indicator traits. When the model was applied to data from two additional herds the cow ranking based on the index was very similar to that based on 200 d weight (r = 0.95 and 0.92 and R2=91.2% and 85.4%). The use of the model will provide commercial herd managers an objective method for culling cows and selecting replacement heifers and may eventually allow the use of data from commercial herds in the calculation of breeding values of stud bulls.

Evaluation of the sulphur hexafluoride tracer technique for methane emission measurement in forage-fed sheep - Pinares-Patino CS; Holmes CW; Lassey KR; Ulyatt MJ (Proceedings of the New Zealand Society of Animal Production, 2007)
The aim of this study was to evaluate the sulphur hexafluoride (SF6) tracer technique for methane (CH4) emission measurement in sheep. Methane emissions from ten Romney sheep were individually measured both by the SF6tracer (‘tracer CH4’) and by the indirect calorimetry chamber (‘calorimetric CH4’) techniques while fed on lucerne hay. The tracer technique involved the use of permeation tubes with pre-calibrated permeation rates (‘pre-calibrated PR’) of SF6. The ‘tracer CH4’ measurements were carried out for 5 days in digestibility crates housed within a covered yard. Sheep were transferred to calorimetry chambers for 3 days acclimatisation, followed by measurement of CH4emission for 3 days. Permeation tubes were recovered at the end of the animal trial and their ‘post-recovery PR’ determined after subsequent weighing for a 6-month period. Although the ‘tracer CH4’ was slightly lower (by 4%) and had larger variation than the ‘calorimetric CH4’ values (18.8±0.4 vs. 19.5±0.6), the two measurement techniques did not differ significantly (P>0.05) in their CH4emission estimates. The ‘post-recovery PR’ was not different (P>0.05) from their ‘pre-calibrated PR’ values, and they were highly correlated to each other (r=0.98, P<0.0001). It is concluded that the tracer technique provides a reliablealternative method for CH4measurement in forage-fed sheep.

Examination of pH in lot fed beef for Japan - Hopkins DL; Cassar JA; Toohey ES; Wynn PC (Proceedings of the New Zealand Society of Animal Production, 2007)
Cattle lot fed for the Japanese market produce carcases of high value and thus downgrading based on meat quality represents a significant cost. The Meat Standards Australia guidelines for the rate of pH fall specify that carcases must not reach pH 6.0 before their temperature reaches 35°C, however limited experimental data suggests this is a common occurrence in heavy carcases produced for the Japanese market. Therefore a study was conducted to confirm this occurrence and to determine the impact of season on the incidence of fast pH fall. 811 carcases were examined from cattle fed for ~150 days, 411 in April and 400 in July. Initial pH (pHi) and temperature were measured on all carcases and then a sub-set of samples (200/season) were measured for traits such as colour, drip loss and protein solubility. pHi was measured on core muscle samples taken from the loin muscle between the 5th/6th ribs prior to entering the chiller. The pH at 35°C was predicted for a subset of 41 carcases based on data collected at the MSA site at the lumbarsacral junction using non linear regression. There was a significant relationship (P < 0.05) between pH at 35°C at the MSA site and the temperature at the sampling site at the 5th/6th rib used for determination of pHi. A large proportion of the carcases were outside the MSA pH/temperature window in both autumn (86%) and winter (95%). Season was found to have a significant effect on pH at 35°C (P < 0.001) and ultimate pH (P < 0.001) with higher values in the autumn and winter respectively. A high incidence of carcases exhibiting a fast pH decline at high temperatures was found, irrespective of season and the significance of this finding is discussed.

Expression of keratin intermediate filament genes in wool follicles of wiltshire sheep - Gordon SW; Yu Z-D; Nixon AJ; Pearson AJ (Proceedings of the New Zealand Society of Animal Production, 2007)
Co-ordinated expression of keratin intermediate filament genes in the wool follicle is essential for the formation of the wool fibre. The expression patterns of three acidic (oKRT31, oKRT35, oKRT38), one neutral-basic (oKRT85) and one acidic inner rootsheath keratin (oKRT27) were localised by in situhybridisation in the wool follicles of Wiltshire sheep. All five genes show distinct expression patterns in the primary wool follicles of the face and lower leg, but have comparable keratinisation zones to their human orthologues. During follicle regression, the expression of these genes is first attenuated distally, gradually becoming restricted to proximal regions before terminating in dormant follicles. The involvement of the expression of oKRT27, oKRT31 and oKRT85, but not oKRT35 and oKRT38, in brush-end formation indicates specialised regulation of keratin expressionin the development of this anchoring structure. Intriguingly, significant differences in the expression of cortical oKRT31, oKRT35, oKRT38 and oKRT85 between primary and secondary follicles were identified.The association of asymmetrical expression of some keratins with follicle curvature raises the possibility of a role infibre crimp formation. Future studies of these and other keratins will generatean understanding of the structural basis of fibre attributes that could contribute to development of novel wool fibres for specific applications.

Expression of the developmental regulators Msx1 and Msx2 in sheep skin varies with body region and wool growth pattern - Craven AJ; Rufaut NW; Scobie DR; Nixon AJ (Proceedings of the New Zealand Society of Animal Production, 2007)
The variability of fibre characteristics affects the processing performance of wool and therefore the value of the wool clip. These variations originate during development in utero, and manifest as patterns of fibre growth that differ between body regions. Two transcription factors, Msx1 and Msx2, have previously been linked to regional specification within the skin and alsoact as regulators of differentiation within the hair follicle matrix. In this study, we describe the expression patterns of Msx1and Msx2in multiple body sites of foetuses and adult crossbreed ewes. In foetal skin, the expression of both Msx1and Msx2was greatest in the regions of lower eventual follicle density. In adults, both anterio-posterior and dorso-ventral gradients were observed in Msx1expression across the fleece bearing skin. Higher concentrations of Msx1and Msx2transcripts were present in adultsthan foetuses, possibly reflecting additional roles in regulating the differentiation and growth of the wool fibre shaft. These results are consistent with the involvement of Msx1 and Msx2 in the development of skin regions, wool follicle growth, and anterio-posterior and dorso-ventral gradients of wool characteristics in sheep

The genetic relationship between heifer and cow fertility - Pryce JE; Harris BL; McNaughton LR (Proceedings of the New Zealand Society of Animal Production, 2007)
Initial predictors of dairy bulls’ fertility proofs are currently limited to body condition score (BCS), milk yield and success of mating in the first 21 days (PM21) for their two-year-old lactating daughters. The first calving rate trait (CR42) is available after a cow has calved for a second time. Obtaining an earlier indication of fertility would be useful for genetic evaluation purposes. The aim of this study was to investigate the genetic and phenotypic control of heifer fertility in addition to investigating the relationship between heifer fertility and traits already included in the prediction ofthe fertility breeding value. Data were available on LIC’s Sire Proving Scheme animals born from 1989 to 2003 and included records on 244,453 animals. Using data on the first calving, planned start of calving was defined as the day within contemporary group when greater than 10% of animals had calved. A multivariategenetic analysis was undertaken with the traits PM21, CR42, BCS and 270-day milk yield recorded in lactating cows, in addition to a heifer fertility trait where success is defined as heifers that calve within21 days from the planned start of calving (CR21). The model fitted to these traits included contemporary group of the milking herd, breed proportions and age at first calving as linear and quadratic effects. The mean CR21 in this dataset was 71%. Heifers failing to calve within 21 days of the herd’s planned start of calving for heifers also had poorer fertility in first lactation, with a least-squares-mean of 75.5% (s.e. 0.2) versus 81.5% (0.1) for PM21 and 54.2% (0.22) and 62.4% (0.1) for CR42. The heritability estimate of CR21 was low (0.012), yet the genetic variation was comparable to other fertility measures. CR21 had a positive genetic correlation with CR42, indicating that CR21 may be a useful early indicator of fertility for use in genetic evaluations.

Genetic technologies for deer breeding - Archer JA; McEwan JC; Hall R (Proceedings of the New Zealand Society of Animal Production, 2007)
The deer industry has made significant progress in developing and applying genetic tools to accelerate genetic gain. This paper briefly outlines the application of current tools (DNA parentage, DNA breed composition and genetic evaluation for growth and velvet), and then suggests a range of other tools which might be used in deer breeding in the future and makes brief comment as to their application. These tools include: genetic evaluation of a wider range of traits; economic indices, mate allocation software, breeding program diagnostic software, enhanced breed composition tests, single gene tests and whole genome selection.

Hair whorl patterns are related to age at puberty and milk-production traits in dairy cattle - Young SK; McNaughton LR; Spelman RJ (Proceedings of the New Zealand Society of Animal Production, 2007)
The objective of this study was to measure facial hair whorl characteristics of Friesian-Jersey crossbred cows (n=658) and to investigate their association withmeasures of milk production, fertility and behaviour. Cows had 1 (n=581), 2 (n=10), 3 (n=1) or no facial hair whorls (n=66). Of those cows with one whorl, 66% had whorls in the middle of the head, whereas 21% had whorls low on their head and 13% high on their forehead. Round whorls were present on 77% of cows, while 23% had non-round whorls. Fifty five percent of cows with round whorls were recorded as havinganticlockwise rotation and 16% of cows as clockwise rotation. Cows with high hair whorlstended to reach puberty earlier on average than cows with lower whorls (P=0.07). Cows with higher non-round whorls also produced lower total milk and total solid yields, than cows with low whorls (P=0.01). No relationship was found between hair whorl characteristics and behaviour in this study.

Impact of early age litter size on subsequent litter output in ewes - Amer PR; Jopson NB; Cocks J; Scarlet AL (Proceedings of the New Zealand Society of Animal Production, 2007)
Data from 28 performance recorded sheep flocks were evaluated to test for effects of litter size early in a ewe's life, on subsequent litter sizes. Ewes lambing twins at 2, 3 or 4 years of age had litters with on average 0.04 to 0.08 more lambs at each subsequent lambing than ewes lambing singles. The corresponding increases for ewes lambing triplets versus singles ranged from 0.23 to 0.26, with retention of the effect through successive litters. When data were adjusted to accountfor a ewe’s lifetime genetic potential for prolificacy, evidence for an antagonistic environmental effecton litter size following a previous large litter was identified. This effect was approximately twice as high for triplets relative to singles (-0.19 to -0.32) when compared with twins relative to singles (-0.09 to -0.18), and declined in its effect on lambings more than one year later. It suggests that preferential treatment ofewes based on their previouslambing performance might improve their subsequent lambing performance. Culling two tooth ewes based on a single lambing record is unlikely to be economically viable, but there may be situations where reduced flushing of two tooth ewes prior to mating might be justified in prolific commercial flocks. The power and limitations of using data from performance recorded flocks to make recommendations relating to management decisions in commercial flocks is discussed.

Induced physical distension of rat mammary glands accelerates the onset of apoptosis and involution compared with milk accumulation alone : Brief Communication - Phyn CVC; Dobson JM; Davis SR; Stelwagen K; Singh K (Proceedings of the New Zealand Society of Animal Production, 2007)
Extended periods of milk accumulation result in reduced milk secretion, increased apoptosis and eventually, involution of mammary glands. The subsequent change in epithelial cell shape from a cuboidal to a flattened morphology as the alveoli distend with milk may initiate changes in protein and gene expression (mechanotransduction) triggering the process of involution (Davis et al., 1999).

Integrated livestock management ... challenges and opportunities of farming deer with other livestock - Nicol AM; Griffiths WM; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2007)
A recent survey indicated that approximately 67% of deer farmers integrate sheepand/or cattle on their deer unit to better match feed demand with the seasonal pattern of pasture growth, maintain pasture quality, particularly during lactation and to control weeds. Integrated stock policies also allow for improved financial risk management and provide flexibility to adjust stock numbers in response to market signals and feed supply. There is evidence from the sheep and beef industries that productivity can be increased from the integration of sheep and cattle compared to a single species system. There is limited information for the integration of sheep and cattle with deer so an assessment of the ‘challenges and opportunities for co-grazing deer with other livestock’ must inevitably rely on extrapolation of knowledge from the co-grazing of sheep, cattle and goats of which there is an extensive literature. This paper identifies the key knowledge needed to meet the challengesand identify the opportunities of grazing deer withother livestock.

Internal parasites and productivity in farmed deer - Hoskin SO; Johnson M; Swanson J (Proceedings of the New Zealand Society of Animal Production, 2007)
The aim of this brief review is to summarise current knowledge of the effects of internal parasites (lungworm and gastrointestinal nematodes) on productivity of farmed red deer. This review, largely based upon published data, highlights gaps in the literature and draws attention to topics for future research.

International drivers for animal welfare change and implications for New Zealand - Matthews LR (Proceedings of the New Zealand Society of Animal Production, 2007)
Standards of animal welfare accepted in the international (mainly European and North American) marketplace are influenced by a wide range of factors, including lobby groups and retailers. In addition, voluntary labelling of products (one of the tools advocated by lobbyists and retailers) is likely to have considerable influence over consumer purchasing choices (for foods derived from animal friendly products and production systems). The EU is determined, through a combination of policy adjustment, research and monitoring of animals, and provision of information, to make improvements to the welfare of animals that contribute to the food supply of European consumers. The changed regimefor CAP payments will mean that systems for monitoring livestock welfare will be in place in Europe from 2007. The EU’s Welfare Quality research project will have a draft set of welfare monitoring standards available for “road testing” at the beginning of 2007. Similarly, validated measurement tools that are relevant to New Zealand conditions are required (to facilitate continued success in premium-priced welfare-sensitive markets). Ideally, the measurement tools and systems need to be outcome-based and applicable to the assessment of all aspects of welfare covered under the Five Freedoms and in New Zealand’s production systems.