@conference {41934, title = {Effect of cow genotype and feed allowance on milk composition}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {397-402}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {The effect of strain of Holstein-Friesian and level of feed allowance on milk composition, individual milk proteins, and minerals was examined in a seasonal calving pastoral dairying system. The trial included two high genetic merit strains of either North American (OS90) or NZ (NZ90) genetics, and one strain representing NZ 1970{\textquoteright}s genetics (NZ70). Each strain was farmed under systems designed to provide total feed allowances of 4.5 to 7.0 t DM/cow/year. Milk composition was affected by strain of cow and by feed allowance. Strain of cow influenced crude protein (P<0.05), true protein (P<0.01) and casein (P<0.01) concentrations, with the NZ90 and OS90 strains having higher concentrations than the NZ70 strain. Increased feed allowance resulted in increased crude protein (P<0.05), true protein (P<0.05) and casein (P<0.05) concentrations. Strain, but not increased feed allowance affected the protein:fat ratio, with the OS90 strain having a higher ratio (P<0.05) than the NZ strains. Strain altered concentrations of {\'a}-casein (P<0.05), with NZ90 having the highest concentrations and NZ70 the lowest concentrations. No consistent effect of strain or feed allowance was determined on whey proteins except for {\^a}-lactoglobulin (P<0.027), where the OS90 strain had higher concentrations than the NZ strains. No consistent effect of strain or increasing feed allowance was seen on milk mineral concentrations. These results demonstrate that different selection and breeding policies have influenced major milk components which may influence milk processing and product characteristics. }, issn = {1176-5283}, author = {Turner S-A and MacDonald KA and Back PJ and Thomson NA} } @conference {41681, title = {Effect of dairy cow breed on the metabolic adaptation to lactation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {390-396}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Three breeds (20 Friesian, 20 Jersey and 20 Jersey/Friesian crossbred multiparous cows) were used to determine the effect of breed on indicators of metabolic status and the post partum anovulatory interval (PPAI). Effect of breed on circulating concentrations of metabolites and hormones, liver mRNA levels and PPAI was established. Weekly blood samples were taken for the first 6 weeks of lactation. Liver biopsy samples were taken from a sub-sample of cows of each breed between 23-33 days post partum, to determine levels of expression of T-GHR, GHR-1A and IGF-1 receptors using RT-PCR. Milk progesterone analysis was used to determine PPAI. There was a significant breed effect on circulating concentrations of {\^a}-hydroxy butyrate (P<0.01), non-esterfied fatty acids (P<0.001), triacylglycerols (P<0.001) and leptin (P<0.01), with Jersey cows having higher concentrations of these hormones and metabolites than Friesian or crossbred cows. Despite the concentration differences between breeds, only leptin showed a significant difference (P<0.01) in the rate of change in concentration across time between the breeds. Jersey cows were observed to have shorter PPAI (34 vs 42 and 44 days for Friesian and crossbred cows respectively: SED 6 days) but this was not statistically significant (P=0.18). There was no difference in the expression of mRNA levels of TGHR, GHR-1A and IGF-1 receptors in the liver. It appears that grazing Jersey cows have a different fat metabolism, which affects the regulation of circulating leptin concentrations and this may have contributed to their apparent ability to return to cyclicity earlier. }, issn = {1176-5283}, author = {Back PJ and Meier S and Barnett CME and Cursons RT and Thomson NA} } @conference {41686, title = {Effects of conjugated linoleic acid on bioenergetics and milk production parameters in grazing dairy cows offered ad libitum or restricted pasture}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {423-428}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Conjugated linoleic acids (CLA) reduce milk fat synthesis in grazing dairy cows and often improve net energy balance (EBAL). Study objectives were to determine if CLA-induced milk fat depression (MFD) could be utilised during times of feed shortage (i.e drought) to improve bioenergetic and milk production parameters. Twelve multiparous mid-lactation rumen-fistulated Holstein cows were offered ad libitum (AL) or restricted (R) pasture and abomasally infused twice daily with 0 (0) or 50 (50) g/d CLA in a cross over design. Treatment periods lasted 10 d and were separated by a 10-d washout period. Milk and plasma samples were averaged from d 9 and 10, and EBAL was calculated from d 6-10, of the infusion periods. Pasture restriction reduced (P<0.05) the yield of milk and milk components. CLA reduced (P<0.01) milk fat yield by 45 and 46 \% in AL and R, respectively. There was no effect of CLA on milk yield nor milk lactose content or yield, however milk protein content increased (P<0.05) in both AL and R, resulting in an increased (P<0.05) protein yield of 6 and 9\% respectively. The CLA-induced changes to milk fat and protein increased (P<0.01) protein:fat ratio by approximately 2-fold in both AL and R. Calculated EBAL improved following CLA infusion (-1.84 vs. 11.22 and 1.59 vs. 13.77 MJ/cow/d for AL and R respectively; P<0.05), however CLA did not alter plasma bioenergetic markers (including insulin, non-esterified fatty acids, {\^a}-hydroxybutyrate, urea and glucose). Data indicate that during short periods of nutrient restriction, CLA may provide an alternative management tool to improve milk protein:fat ratio and calculated EBAL, however further studies are required to determine if CLA is effective at improving bioenergetic parameters during more severe nutrient restriction. }, issn = {1176-5283}, author = {Kay JK and Mackle TR and Bauman DE and Thomson NA and Baumgard LH} } @conference {41890, title = {Supplementing dairy cows with oils to improve performance and reduce methane ? does it work?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {176-181}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Oil supplements can be used in dairy rations to increase dietary energy density (and energy intake) and reduce methane (CH4) emissions from rumen fermentation. Trials at Dexcel measured effects of oil supplementation on dry matter intake (DMI), milk yield and methane production after lactating dairy cows were fed pasture-based diets for short (14-day) and long (12-week) periods. In the short-term trial, 32 cows received either no oil or three mixtures of sunflower and fish oil at 500g/d. In the long-term trial 20 cows grazed pasture and received either no oil or 300g linseed and fish oil for 11 weeks prior to methane measurements. The type of oil in the short-term trial did not affect methane production and oils had no effect on DMI or milk yield but reduced total methane emissions by 27\% (176 vs. 242g CH4/cow/d, sed=10.6) and CH4/kg DM (13.5 vs. 18.5g CH4/kg DM, sed=0.88). In the long-term trial, oil had no effect on methane emissions (353 (oil) vs. 323g CH4/cow/d (control), sed=17.0 and 21.7 vs. 23.0g CH4/kg DM, sed=1.01). These trials did not show benefits of oils for milk production and emphasize the need for longterm studies when developing on-farm strategies for methane mitigation. }, issn = {1176-5283}, author = {Woodward SL and Waghorn GC and Thomson NA} } @conference {41835, title = {Condensed tannins in birdsfoot trefoil (Lotus corniculatus) affect the detailed composition of milk from dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {283-289}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Feeding birdsfoot trefoil (lotus, Lotus corniculatus) to dairy cows increases milk solids production and reduces methane production relative to ryegrass pasture. This study has measured the affect of lotus and lotus condensed tannins (CT) on milk protein and lipid composition. The trial involved 32 Friesian dairy cows offered either good quality perennial ryegrass pasture or lotus. Half of the cows given each diet were drenched with polyethylene glycol (PEG) to inactivate the CT. A daily milk sample was collected from all cows prior to and towards the end of the treatment period. Gross milk fat and milk protein concentrations were similar for cows fed lotus or ryegrass. Neither feed, nor CT affected individual proteins in the milk with the exception of lactoferrin (Lf) where the CT in lotus increased concentrations (138 vs 76 mg/l; P < 0.01). Forage type affected the composition of fatty acids (FA) in the milk with cows gazing lotus having higher concentrations of de novo synthesised (C4:0-C15:0; 28.3\% vs 26.7\%; P < 0.01) and lower concentrations of pre-formed (C17:0 and longer; 34.5\% vs 39.0\%; P < 0.05) FA than those grazing ryegrass. The CT in lotus appeared to affect ruminal biohydrogenation of FA, decreasing the concentration of saturated FA in the milk fat, and increasing in the concentrations of the omega-3 FA (1.5\% vs 1.1\%; P < 0.01). Changes in the saturation and proportions of FA may affect processing characteristics and functionality of milk from cows fed lotus. CT in lotus may also provide potential new avenues for increasing milk value on-farm. KEYWORDS: detailed milk composition; Lotus corniculatus; condensed tannins. }, issn = {1176-5283}, author = {Turner S-A and Waghorn GC and Woodward SL and Thomson NA} } @conference {41834, title = {The effect of genotype on milk composition, milk value and dairy farm profitability}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {276-282}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {This study was conducted to determine the effect of genotype on milk composition, milk value and economic farm surplus (EFS). The trial included two high breeding worth ($BW) strains of either North American (OS90) or New Zealand (NZ) (NZ90) genetics, and one low $BW strain of NZ genetics (NZ70). Each strain was farmed under systems designed to provide total feed allowances of 4.5 to 7.0 t DM/cow/year. For two years (2001/2002 \& 2002/2003) monthly average milk yield and composition were determined for each of the 11 herds. A simulation model was used to calculate milk value using three product mixes. Using either the simulated values or actual values (paid by Fonterra 2002/2003) for milk and its components, milk value ($/litre and $/kg milksolids (MS)) and an EFS for each herd was determined. The OS90 strain produced milk with lower concentrations of fat and protein and higher protein:fat ratio than NZ70 or NZ90 strains. The effect of strain on milk price was unaffected by product mix. Milk value differed between strains irrespective of method of determination. Milk value expressed as $/kg MS was lowest for the NZ70 and highest (P < 0.001) for the OS90 strain. When expressed as $/litre milk value was highest (P < 0.001) for the NZ90 strain. Milk value expressed as $/kg MS was positively associated with protein:fat ratio whereas milk value expressed as $/litre was positively associated with MS concentration. Average EFS was greater for the NZ90 than the NZ70 strain and was least for the OS90 strain. The factors associated with EFS were MS production; milk value and milk composition had minimal impact. New Zealand{\textquoteright}s dairy cattle breeding programme has produced a strain of Holstein- Friesian with increased milk fat and protein concentration, an increased protein:fat ratio, and an associated increased milk value and increased EFS. In comparison, the OS90 strain which the current $BW index ranks as high as the NZ90, produced milk with higher value ($/kg MS) but resulted in lower EFS. Key words: milk price; milk value; milk composition; economic farm surplus. }, issn = {1176-5283}, author = {Thomson NA and Turner S-A and Glassey CB and Lopez-Villalobos N} } @conference {41536, title = {Exploiting cow genotype to increase milk value through production of minor milk components}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {53-58}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Milk value could be increased on-farm by supplying milk with enhanced concentrations of minor compounds that have bioactive properties. Compounds of interest in this study were the whey proteins lactoferrin (Lf) and lactoperioxidase (LP), and milk fatty acids; particularly conjugated linoleic acid (CLA) and omega-3 fatty acids. Mixed genotype cows (20 Friesian, 20 Jersey and 20 crossbred) were sampled to determine the effect of cow genotype and age on Lf concentration, Lf yield and LP activity at 4 times during the season. In milk fat, concentration of CLA and omega-3 fatty acids were determined twice during the season. Cow genotype had no effect on Lf concentration but age did (P < 0.002), with 4-year and older cows producing greater concentrations in milk than 3 year old cows. For harvesting Lf, Friesian cows would be the most profitable, with the greatest Lf yields, particularly in mid-late lactation. The highest LP activity levels throughout lactation were demonstrated in Jersey milk. In milk fat, Friesian cows produced milk of a putatively healthier profile, with greater concentrations of unsaturated fatty acids, CLA and omega-3 fatty acids. Key words: milk value; cow genotype; lactoferrin; lactoperoxidase; conjugated linoleic acid; omega-3 fatty acids. }, issn = {1176-5283}, author = {Back PJ and Thomson NA} } @conference {41836, title = {A model system to investigate the regulation of lactoferrin production by the bovine mammary gland}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {290-296}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Lactoferrin (Lf) is a high value, low concentration protein found in milk. Lf concentrations are found to increase during mastitis. This study was instigated to investigate if the effect of inducing sterile inflammation of the mammary gland, using lipopolysaccharide (LPS), a component of bacterial cell walls, would be a useful physiological model to study the production of Lf. Ten multiparous Friesian-Jersey cross-bred (FxJ) cows (approximately 200 days in milk) with no recent history of mastitis were utilised. All cows were milked on an individual quarter basis, and milk samples were collected one week prior to the treatment date to provide covariate data. Eight cows were infused via the teat canal with 10 ml saline and 10 μg LPS in 10 ml saline into 2 random quarters on each cow. The other two quarters on each cow were not treated. Two cows were untreated controls. All cows were milked twice daily with milk samples collected individually from all 4 quarters for 7 days with additional samples collected at 14 and 21 days. All milk samples were analysed for gross composition (fat, protein, lactose), somatic cell count (SCC), conductivity and Lf concentration. At the first milking after treatment, LPS treatment showed a significant effect on all milk components measured. By the 4th milking after treatment Lf concentrations were approximately 3.5 fold higher in LPS treated quarters compared with saline infused quarters, and remained elevated until 7 days after treatment. SCC remained elevated (P < 0.01) in the LPS treated quarters until day 7 also. These results show that LPS can be used to induce the production of Lf in lactating cows and therefore provides a model with which to further investigate the mechanisms that control Lf production. KEYWORDS: lactoferrin; lipopolysaccharide; endotoxin; somatic cell count; conductivity; milk composition. }, issn = {1176-5283}, author = {Turner S-A and Thomson NA} } @conference {41412, title = {Diet and genotype affect milk lactoferrin concentrations in late lactation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {63}, year = {2003}, month = {Jan}, pages = {87-90}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Queenstown}, abstract = {Although lactoferrin (Lf) is a valued milk protein, little information is available on factors that affect its concentration in milk. Milk samples were collected during late lactation to determine if diet or cow genotype affected the concentration and yield of Lf in bovine milk. Holstein-Friesian (HF) cows (n=52) of either overseas (OS) or New Zealand (NZ) ancestry were fed either an all-pasture diet or a total mixed ration (TMR). Milk samples were collected from each cow during an AM milking in early March and late April. NZHF had a higher (P<0.05) Lf concentration than OSHF even though they produced less (P<0.05) milk. Genotype did not affect Lf yield, somatic cell count or the proportion of bacteriologically negative quarters. The Lf concentration in the milk of cows fed TMR was higher (P<0.05) than cows grazing pasture in April but not in March. Cows fed TMR also produced more (P<0.05) milk and a greater (P<0.001) yield of Lf than cows grazing pasture. Diet did not affect SCC, however only cows fed TMR had any bacteriologically positive quarters. A positive within-cow correlation (P<0.001) was found between Lf and SCC. The effect of diet on the concentration of Lf in milk requires further investigation. The genotype results suggest that NZHF have higher concentrations of Lf in milk than OSHF. Naturally high concentrations allow improved extraction efficiencies of Lf during processing. }, issn = {1176-5283}, author = {Turner S-A and Williamson JH and Thomson NA and Roche JR and Kolver ES} } @conference {41416, title = {Diurnal variation in blood plasma metabolites and insulin of lactating dairy cows grazing pasture and supplemented with a high-lipid supplement either once or twice a day}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {63}, year = {2003}, month = {Jan}, pages = {107-111}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Queenstown}, abstract = {The experiment determined the diurnal variation of a blood plasma hormone and three metabolites (insulin, glucose, NEFA and triglyceride) and how these varied with different frequencies of supplementary feeding. Twenty-four cows in early lactation (DIM 81 {\textpm} 20) were divided randomly into three treatments; grazed pasture only and pasture supplemented with 2 kg/cow/day of ruminally protected oilseed supplement (metabolisable energy 19 MJ/kg DM) either once a day after morning milking or twice a day after morning and afternoon milking. On day 12 of the experiment, 12 cows (4 cows/treatment) were jugular catheterised and commencing at 1600 h, blood sampled at 2-hourly intervals for 24 h. This protocol was repeated for the remaining 12 cows on day 13 Concentrations of the selected blood plasma hormone and metabolites varied diurnally (P<0.001). The difference between the average peak and nadir concentrations over the 24 hours were 54\%, 66\%, 224\% and 63\% for plasma insulin, glucose, NEFA and triglyceride respectively. Feeding the lipid supplement increased blood plasma NEFA (P<0.01), and triglycerides (P<0.001) but had no effect on insulin, or glucose concentrations. Frequency of supplementary feeding influenced (P<0.05) the diurnal variation of NEFA but not, insulin, glucose, or triglyceride. Concentrations of NEFA, glucose, and triglyceride were variable between 0600 h and 1000 h and stabilised between 1600 h to 2000 h. Plasma insulin concentrations were low and stable between 0400 h to 0800 h. Consideration of diurnal variation and the stability of the blood plasma components measured led to the recommendation that the best time to blood sample for insulin is between 0400 - 0800 h and for glucose, NEFA, and triglyceride, between 1600 2000h. }, issn = {1176-5283}, author = {Thomson NA and Singh K and Kay JK} } @conference {41398, title = {Predicting Delta9-desaturase activity and the association with conjugated linoleic acid (CLA) concentration in bovine milk}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {63}, year = {2003}, month = {Jan}, pages = {25-30}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Queenstown}, abstract = {The major source of cis-9, trans-11 conjugated linoleic acid (CLA) in bovine milk is from the post-ruminal conversion of trans-11 C18:1 (TVA) by D9-desaturase. Activity of D9-desaturase is predicted from the product/substrate ratios of fatty acids dependant on the enzyme. Data from three experiments was investigated. Cows selected for having soft or hard milk fat were fed ruminally protected oilseed in spring 1999, and autumn 2000 or crushed full-fat rapeseed in autumn 2001. Cows with harder milk fat had higher concentration of milk fat (P<0.001), and lower concentrations (P<0.001) of TVA and CLA. Feeding ruminally protected oilseed in spring had no effect on milk fat, TVA or CLA concentrations but in autumn increased (P<0.001) milk fat concentration. Feeding crushed rapeseed depressed (P<0.001) TVA and CLA concentrations. Ratios of fatty acid pairs dependent on D9-desaturase (C10:1/C10:0, C16:1/C16:0 cis-9 C18:1/C18:0 and CLA/TVA) were lower in milk from cows with harder milk fat and the C12:1/C12:0, C14:1/C14:0 ratios were similar for soft and hard milk fat cows. Feeding ruminally protected oilseed decreased (P<0.001) all ratios except for C12:1/C12:0 in autumn 2000. Feeding rapeseed had no effect on the product/substraight ratios except the cis-9 C18:1/C18:0 ratio. None of these ratios were associated with milk fat CLA concentrations in spring however in autumn C14:1/C14:0 and C16:1/C16:0 were positively associated (P<0.05). Significant associations (P<0.001) between the milk fat cis-D9 C18:1/C18:0 ratio and CLA concentration and between TVA and CLA concentrations were also evident. This suggests that milk fat CLA concentrations may be influenced more by the availability of TVA than by the variation in the activity of D9-desaturase. }, issn = {1176-5283}, author = {Thomson NA and Chand A and Kay JK} } @conference {41359, title = {Concentrations of conjugated linoleic acid in milk from cows grazing pasture of fed a total mixed ration for an entire lactation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {240-241}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

Conjugated linoleic acid (CLA) is a collective term for the range of conjugated isomers of linoleic acid (C182). These fatty acids occur naturally in milkfat and have proven anticarcinogenic properties in laboratory rodents (Ip et al., 1999). Additionally, the various isomers have other reputed benefits for human health such as enhanced bone mineralisation, antidiabetic effects, reduced atherosclerosis and immune system modulation (Whigham et al., 2000). Such potential benefits for human health have focussed international research on enhancing concentrations of CLA in milk and dairy products. Overseas data show that one way to increase the concentrations of CLA in milk is to change the diet of cows from a typical total mixed ration (TMR) to pasture (Kelly et al., 1998; White et al., 2001). This points to a potential competitive advantage for the New Zealand dairy industry, in which pasture is already almost the sole source of feed. Despite this there are no data confirming the beneficial effects of pasture for enhancing CLA under New Zealand grazing conditions. The experiment described here used an existing experiment to compare the concentrations of CLA in milk from cows fed TMR or grazing pasture for an entire lactation under New Zealand conditions.

}, issn = {1176-5283}, author = {Audlist MJ and Kay JK and Thomson NA and Napper AR and Kolver ES} } @conference {41309, title = {Effect of body condition at calving of milkfat composition of Friesian heifers during the first ten weeks of lactation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {38-41}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {The effects of live weight and body condition score (CS) at calving on milksolids production has been well documented. The effects of CS at calving on detailed composition of milk, the physical characteristics, or, product quality are largely unknown. Milkfat yield, fatty acid profile (FAP), solid fat content (SFC) of milkfat during the first 10 weeks of lactation were monitored for Friesian heifers with a pre-calving CS of 4.1 (LCS) or 5.2 (HCS). Once calved, all heifers were grazed as one herd and offered pasture ad libitum. Composition and characteristics of milkfat were determined at four, six, and 10 weeks postpartum. At four weeks postpartum the HCS heifers, produced 23\% more (P<0.001) milkfat, lost 59\% more (P<0.001) live weight and CS declined 30\% more (P<0.05) than did LCS heifers. Associated with these changes were compositional changes in milkfat. CS at calving had no effect on milkfat concentration. HCS heifers produced milkfat with lower concentrations (P<0.01) of de novo synthesised fatty acids (C4:0-C15:1) and higher (P<0.01) concentrations of preformed fatty acids. Concentration (mg/100 mg milkfat) of oleic acid (C18:1) was higher: 27.4\% c.f. 24.8\%, s.e.d. 0.94 (P<0.001) for HCS compared with LCS heifers. Milkfat from HCS heifers was softer, SFC at 5{\textdegree}C (55\% c.f. 59\%, s.e.d. 1.2, P<0.01) than from LCS heifers. Six weeks postpartum, the differences in FAP persisted but changes in live weight and CS were small compared with the first four weeks of lactation. Ten weeks post calving both groups were gaining live weight, but although differences (P<0.01) in live weight, CS, and daily milkfat yield persisted, no differences in FAP or SFC were found. These results show that differences in pre-calving live weight and CS cause differences in the composition and characteristics of milkfat. Milkfat from HCS heifers was more desirable (softer and higher in unsaturated fatty acids) than from LCS heifers. These differences disappeared once the two heifer groups were in positive energy balance by 10 weeks postpartum. }, issn = {1176-5283}, author = {Thomson NA and Bryant MO and Chand A and MacGibbon AKH and Chagas LM} } @conference {41310, title = {Effects of time-of-calving on dairy production: a farmlet study}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {42-43}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {Most dairy cows in New Zealand are calved just prior to spring in order to maximise pasture utilisation. This practice is associated with marked irregularities in the volume and composition of milk supplied to factories, which is a major limitation of seasonally-calving, pasture-based dairying systems. The need to accommodate peak milk flow means that manufacturing plants are underutilised for most of the season. Further, changes to milk composition can make it difficult to manufacture dairy products of high quality during some parts of the season, which necessitates the storage of product to meet out-of-season demand. Such irregularities are caused by a number of factors, including nutritional factors associated with the changing quality and availability of pasture, and physiological and hormonal factors associated with the stage of lactation of the cows (Auldist et al., 1997). One way of manipulating the lactation curve of the cows may, therefore, be to adjust the time of the year at which calving occurs. A previous study in New Zealand showed that autumn calving herds could be as profitable as spring calving herds (Garcia et al., 1998). In that study, nutritional demands were matched with pasture availability by adjusting stocking rate and feeding varying amounts of pasture and maize silage when required. A premium for winter milk was also applied. The current study was designed to investigate the effects of calving at four different times of the year on milk production in farmlet systems which were otherwise similar in stocking rate and other farm management variables. }, issn = {1176-5283}, author = {Audlist MJ and MacDonald KA and Thomson NA and Coulter M and Lancaster JAS and Penno JW} } @conference {41302, title = {Endogenous synthesis and enhancement of conjugated linolieic acid in pasture-fed dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {12-15}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {The primary conjugated linoleic acid (CLA) isomer in milkfat, cis-9, trans-11 CLA, is a proven anticarcinogen in rodents and can be derived directly from ruminal biohydrogenation of linoleic acid. The major fatty acid in pasture, however, is alpha-linolenic acid; the biohydrogenation of which does not produce cis-9, trans-11 CLA as an intermediate. Therefore, in grazing cows, cis-9, trans-11 CLA must be produced by other sources, possibly via D9-desaturation of trans-11 vaccenic acid (TVA), a biohydrogenation product of both alpha-linolenic acid and linoleic acid. Studies were conducted to i) determine the importance of endogenous synthesis of cis-9, trans-11 CLA in pasture-fed cows and ii) increase the level of cis-9, trans-11 CLA. The first study involved abomasal infusion of sterculic oil (SO) to inhibit the activity of the D9-desaturase enzyme. Abomasal infusion of SO decreased the concentration of cis-9, trans-11 CLA in milk fat by 71\% (P<0.01; 3.6 c.f. 12.1 {\textpm} 0.15 mg/g fatty acid). The presence of cis-9, C 1 0:1, cis-9, C12:1 and cis-9, C14:1 in the milk fat of cows following SO treatment indicated D 9-desaturase was not completely inhibited. Using the changes in these fatty acids to evaluate the extent of D9-desaturase inhibition with SO treatment, an estimated 87-100\% of cis-9, trans-11 CLA in milk fat was of endogenous origin. In the second study, sunflower oil at 4\% DMI/cow/day invoked a 38\% increase (P<0.01) in milk fat TVA (61.3 c.f. 44.4 {\textpm} 0.51 mg/g fatty acid) and a subsequent 28\% increase (P<0.01) in cis-9, trans-11 CLA concentrations compared to control (28.5 c.f. 22.3 {\textpm} 0.19 mg/g fatty acid). Results demonstrate that endogenous synthesis is the major source of cis-9, trans-11 CLA in pasture-fed dairy cows and levels can be enhanced by increasing the supply of the ruminally-derived precursor, TVA. }, issn = {1176-5283}, author = {Kay JK and Mackle TR and Auldist MJ and Thomson NA and Bauman DE} } @conference {41324, title = {On-farm management to modify milkfat composition - a review of experiments undertaken at Dexcel to produce a spreadable butter directly from the cow}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {100-103}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {For many years it has been known from overseas studies that the composition and physical characteristics of milkfat are influenced by diet. The feeding of oilseeds had been shown to reduce the concentration in milkfat of short- and medium-chain-length fatty acids and to increase the concentration of long-chain unsaturated fatty acids. It was also reported that these changes resulted in softer milkfat and butter with improved spreadability at low temperatures. With this knowledge, a six-year collaborative research programme between the New Zealand Dairy Research Institute and Dexcel was undertaken to investigate the economic feasibility of producing a spreadable butter directly from the cow. The programme investigated the influence of each component in pastoral dairying that may possibly influence milkfat composition. These were: pasture, (location, defoliation interval, and species effects) on pasture lipid composition, grazed pasture effects (species and grazing rotation), supplementary feed effects (ruminally and non-ruminally protected oilseeds), frequency of feeding, and milking management. Following the study of each component the various components will be combined to develop a total farm management system to achieve the programme{\textquoteright}s goals. The goal of producing a spreadable butter directly from the cow has been achieved, but the programme has yet to develop a profitable farm system to produce the product under existing returns for milksolids.}, issn = {1176-5283}, author = {Thomson NA and Auldist MJ and Kay JK and MacGibbon AKH and Murphy JJ} } @conference {41325, title = {Producing a spreadable butter using modified milkfat}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {104-107}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {While traditional butter has been the spread of choice for many years because of the full flavour and excellent storage properties, since the advent of household refrigerators the lack of spreadability of butter when taken directly from the refrigerator has been seen as a negative characteristic. The approach taken in this study was to modify the composition of the milk from the cow through feeding trials carried out at Dexcel. However the final product must be able to be processed through a dairy plant and to have the performance that the customer requires. This means that it is not enough to know that the composition has changed but that the physical properties produced by these changes are advantageous. The goal therefore was to make the link between the properties required and to work to produce modifications that would produce those properties. This was achieved by defining the links between the product and the milkfat composition and making the physical properties such as solid fat content a target. The goal of producing a spreadable butter using modified milkfat was achieved however there is still a need to develop a profitable farm system. }, issn = {1176-5283}, author = {MacGibbon AKH and van der Does YE and Mabey BG and Deller GJ and Thomson NA} } @conference {41289, title = {Effect of stage of lactation on the efficiency of Jersey and Friesian cows at converting pasture to milk production or liveweight gain}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {61}, year = {2001}, month = {Jan}, pages = {213-216}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {A study comparing Jersey (J) and Friesian (F) cows in early (EL), mid (ML) and late (LL) lactation and offered either ad libitumpasture (P) or restricted pasture allowance + a concentrate (PC) was conducted. Breeds were grazed at a similar live weight (LWT)/ha (1340 and 1850 kg LWT/ha for P and PC respectively). F cows produced 10\% more MS/cow/day than J cows. DM intake (DMI) on P was 13.6 kg DM/cow/day for F and 11.3 kg DM/cow/day for J cows but if expressed at constant LWT, J consumed more than F cows (30.3 versus 28.0 + 0.8 g DMI/kg LWT). During EL, J cows gained less live weight than F cows but in LL the reverse occurred. An interaction between breed and stage of lactation also occurred for the conversion efficiency of pasture DM to milkfat, protein, casein and MS. For the yield of milkfat, protein and casein J cows in EL were more efficient than F cows but in LL no breed effect on the conversion efficiency of pasture to these components occurred. The difference between breeds in partitioning feed to milk solids and liveweight gain at different stages of lactation suggests different management opportunities for each breed to more efficiently convert pasture to MS.}, issn = {1176-5283}, author = {Thomson NA and Kay JK and Bryant MO} } @conference {41228, title = {Effect on milk characteristics to supplementing cows on a restricted pasture allowance with different amounts of either turnips or sorghum}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {60}, year = {2000}, month = {Jan}, pages = {320-323}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {The effect of supplementary feeding 0, 4 or 8 kg DM/cow/d of turnips or sorghum to cows offered a restricted pasture allowance (25 kg DM/cow/d) on milk characteristics (fat, protein and lactose, N fractions, serum proteins, fatty acids (FAP) and solid fat content (SFC)) was investigated. Thirty identical twinsets were used (10 cows/treatment) in a partial cross-over designed experiment comprising two, 10-day periods. Sorghum was higher in fibre (NDF, 65\% v 23\%), total lipid (3.5\% v 1.5\%) and similar for crude protein (9.6\% v 12.0\%) than turnips. Lipid composition differed between crops; turnips had more lauric (C12:0) and less linolenic (C18:3) fatty acids than sorghum. Differences in the chemical composition of the crop were reflected in different milk compositions. Milkfat content was lower for cows fed turnips than sorghum and the effect was greater (P<0.001) with increasing amount of turnips fed (5.5\%, 5.1\% and 5.0\% for 0, 4, and 8 kg DM/cow/d respectively). Milkfat composition also differed for cows fed turnips compared to sorghum. With an increased amount of turnips fed, short, medium and long-chain fatty acids increased (P<0.001) and total unsaturated fatty acids decreased (P<0.001). As a consequence, SFC (an indication of milkfat hardness) also increased. Conjugated linoleic acid (cis-9- trans-11-C18:2) declined (P<0.001) as the level of supplementation with crop increased. The effect was greater (P<0.001) with turnips than sorghum. Compared with the fat components in milk the treatments had minimal effect on milk protein and nitrogen fractions. Feeding cows turnips compared to sorghum decreased (P<0.001) milk urea levels and increased (P<0.001) casein: whey protein ratio. This ratio declined (P<0.05) with increasing rates of supplementation with sorghum. These results show that different feed types can change milk components that influence the efficiency of milk processing, physical characteristics and nutritive value of the final dairy products. }, issn = {1176-5283}, author = {Thomson NA and Clark DA and Waugh CD and van der Poel WC and MacGibbon AKH} } @conference {41226, title = {Seasonal variation of the fatty acid composition of milkfat from Friesian cows grazing pasture}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {60}, year = {2000}, month = {Jan}, pages = {314-317}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Information collected at the Dairying Research Corporation milk composition laboratories on the fatty acid composition of milkfat spanning 1994/95 to 1998/99 dairying seasons has been summarised. The data comprised 1350 determinations in 18 different experiments from 965 individual Friesian cows that calved in July/August and grazed solely on pasture. A seasonal effect on fatty acid composition was observed. In general, concentrations of fatty acid groups and individual fatty acids were similar in spring and autumn but differed in summer. The ratio of an estimate of preformed (total fatty acids >C 17:0 ) and an estimate of de novo- (total fatty acids ad lib., lucerne hay (L) + 1 kg concentrate/animal/day (LC) and ad lib. pasture hay (P) in a 2 x 2 Latin square designed trial. The two hays had similar ME values; L, 8.5 and P 8.7 MJ/ME/kg DM, but differed (P<0.05) in protein content; L, 14.6\% and P 10.1\%. The concentrate was 13.5 MJ ME/kg DM and 14.1\% protein. Animals were fed in a feed-lot with individual pens/treatment. Intake was assessed on a group basis for all treatments and individual animal intake was assessed for the P treatments only using slow release chromium capsules. Two, 4 week experimental periods were preceded by a 2 week feed adjustment period. Liveweight gains showed a species x fed interaction (P<0.001) with individual treatment gains (kg/day) of; 0.80, -0.54, -0.02, -0.09 for CLC, CP, BLC, and BP groups respectively. Cattle consumed (group assessment) more (P<0.05) L Hay than buffalo; 127 vs 99 g DM/kg LWT0.75. The intake of P hay was similar for each species; 102 and 100 g DM/kg LWT0.75 for C and B respectively. The release of CR2O3 from the capsules were similar for the two species (1.56 g/day). Intakes of P hay assessed by the marker techniques differed (P<0.05); 100 and 88 g DM/kg LWT0.75 for the CP and BP treatments respectively. The difference in performance of the two species on P may have been the result of the marginal (for cattle) protein levels. No explanation is given for the poor performance of buffalo on the LC ration. }, issn = {1176-5283}, author = {Thomson NA and Death AF and Power MT} } @conference {40601, title = {A comparison of the carcass and meat quality of Awassi-cross and Texel-cross ram lambs}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {209-214}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The Awassi is a fat-tailed sheep breed from the Middle East that has recently been imported into New Zealand for live-sheep export and for milk production. The aim of the current trial was to compare the carcass and meat quality of Awassi-cross and Texel-cross ram lambs. There were 36 lambs in each sire-breed group with an equal number from Romney and Poll Dorset ewes. Lambs were allocated at random within breed-cross groups to groups of 9 that were slaughtered in either May or August to give an overall mean carcass weight of 19.7kg. The Awassi-sired group had a lower dressing-out percent (44.4 vs 44.8; P<0.01), similar GR tissue depths (7.6 vs 8.4 mm) but more weight-adjusted leg fat (537 vs 446g. P<0.001). The most clear-cut difference was in carcass shape with Awassi-cross lambs having longer carcasses (1068 vs 1013 mm), longer legs, and longer, heavier leg bones at a constant carcass weight (all P<0.001). The shape difference at a common carcass weight was also reflected in the Awassi-cross lambs having lower leg muscle to bone ratios (3.49 vs 3.88), muscle weight (2047 vs 2172 g), and muscularity values (0.436 vs 0.488) than the Texel-cross lambs, and shallower longissimus muscle depths (28.0 vs 29.8 mm)(all P<0.01). Differences between Awassi and Texel-sired lambs in tenderness (shear values) and colour (L*,a*,B* values) of the semimembranosus muscle were not significant. Differences between dam-breed groups were generally small, although, relative to the Poll Dorset, the Romney-cross group had lower weight-adjusted longissimus depths (28.2 vs 29.6 mm) and leg muscle to bone ratios (3.57 vs 3.80(both P<0.01). When adjusted to the same carcass weight, lambs slaughtered in August had lower dressing-out percentages (42.6 vs 46.6), lower GR depths (6.7 vs 9.3 mm, longer carcasses (1063 vs 1018 mm), and poorer leg muscularity (0.450 vs 0.474) than those slaughtered in May (all P<0.02). In this study Awassi-cross carcasses were inferior to those of Texel-cross lambs in terms of composition and shape, but differences in meat quality not apparent. }, issn = {1176-5283}, author = {Holloway IJ and Purchas RW and Power MT and Thomson NA} } @conference {40571, title = {The effect of block and paddock grazing in winter on cow behaviour, cow performance and herbage accumulation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {91-94}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Two management methods for wintering dry cows on pasture (block and paddock) were compared at the Taranaki Agricultural Research Station over a 45 day period. Treatment effects on aggressive behaviour, grazing behaviour and liveweight gain were measured in addition to effects on pasture treading damage and subsequent herbage accumulation. The block grazed group had an area of 25 m2/cow/day, and were confined to a new area (0.1 ha) of pasture each day. The paddock grazed group had an area of 125 m2/cow/day, grazing the total paddock area (0.5 ha) over five days. There were 32 cows and 8 heifers in each treatment group. Agonistic activity in the paddock group was 50\% lower in week one and 28\% lower in week six, than the block group. Paddock cows and heifers gained more liveweight (p<0.01) than block cows and heifers; 0.22 and 0.24 kg/animal/day more respectively. Herbage accumulation over the subsequent three months (July - September) was 290 kg DM/ha lower (p<0.05) on the paddock grazed areas compared to block grazed areas. Paddock grazing reduced agonistic activity among heifers and cows and gave higher liveweight gains. Some of this advantage could possibly be negated by lower herbage accumulation in the subsequent three months. }, issn = {1176-5283}, author = {Judd TG and Thomson NA and Barnes ML} } @conference {40570, title = {The effect of different perennial ryegrass cultivars on dairy animal performance}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {87-90}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A study at the Taranaki Agricultural Research Station investigated possible limitations to dairy production due to recently released ryegrass cultivars. Dairy animals grazed pure swards of either Yatsyn-1, Embassy, Vedette or Pacific in a series of three trials from February 1992 to April 1993. Three ryegrass cultivars (Yatsyn-1, Embassy and Vedette) were infected with the endophyte Acremonium lolii. Pacific was infected with an Acremonium endophyte, strain 187B. In trial 1 (autumn 1992) liveweight gain of dairy calves grazing the respective cultivars over eleven weeks were monitored. Trial 2 (spring 1992) and trial 3 (summer/autumn 1993) were each conducted over 3 consecutive 8 day periods using dairy cows. Liveweight gain and ryegrass staggers were monitored in trial 1, and milk volume and composition in trials 2 \& 3. Herbage mass before and after grazing, dry matter disappearance, botanical composition, lolitrem b, in-vitro digestibility and crude protein levels were measured on each occasion, and ergovaline levels in trial 3. Ryegrass cultivar had no effect on calf liveweight gain. Ryegrass staggers were encountered in calves grazing Yatsyn-1, Embassy and Vedette but not in Pacific. In spring and in February and March of the summer/autumn trials, ryegrass cultivar had no effect on milk production or composition. Milksolids production from Yatsyn-1 was lower (P<0.05) than from Vedette and Pacific in April. Lolitrem content of Pacific was lower (0.14 ug/g grass) and ergovaline content higher (0.99 ug/g grass) in comparison to the other ryegrasses. There was no difference between cultivars in pasture utilisation, botanical composition, digestibility or crude protein levels. It is concluded that ryegrass cultivar or endophyte strain had little effect on dairy animal performance. }, issn = {1176-5283}, author = {McCallum DA and Thomson NA} } @conference {40610, title = {Growth rates, wool production and health of Awassi and Texel crossbred ram lambs}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {247-250}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Birth and weaning weights, liveweight gain, wool weights and characteristics, and animal health were recorded on 214 ram lambs consisting of about equal numbers of Awassi and Texel cross Romney, Coopworth and Dorset ram lambs. Changes in blood GGT concentrations were also measured in Awassi x Coopworth and Romney ram lambs following dosing with sporidesmin. Pre- and post-weaning growth rates of Awassi crossbreds were lower (P<0.001) than Texel crossbreds. Awassi crossbreds had a higher incidence of footscald and higher (P<0.05) strongyloid egg counts in their faeces in May. After dosing with sporidesmin blood GGT concentrations were higher (P<0.001) in Awassi x Coopworth than Romney ram lambs. Awassi crossbreds had lower (P<0.001) fleece weights and wool quality than Texel crossbreds. }, issn = {1176-5283}, author = {Knight TW and Thomson NA and Power MJ and Gallen J} } @conference {40537, title = {A comparison of carcass and meat characteristics and organ weights of castrate and entire male buffalo and cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {407-412}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Research has shown that sheep from a Massey University flock selected for increased fleece weight (FW) for thirty-six years have higher faecal egg counts (FEC) than unselected controls (C). The purpose of this trial was to determine whether differences in FEC between FW and C sheep accurately reflected differences in adult worm burdens. In addition levels of mucosal mast cells, and their relationship with worm burden in each line were examined. Thirteen one year-old rams from each flock were housed indoors and artificially infected with larvae of three species of nematode parasite: Haemonchus contortus, Ostertagia circumcincta, and Trichostrongylus colubriformis. FECs were monitored and adult worm burdens, and levels of mucosal mast cells, determined following slaughter 28 days after infection. FECs were higher in FW than C sheep (4204 vs 300 epg, p<0.0001), as were numbers of adult Haemonchus (1151 vs 249, p<0.01) and Ostertagi (2268 vs 600, p<0.05). Numbers of Trichostrongylus (5838 vs 5266) and total worm burden (9257 vs 6115) were not significantly different between lines. A {\textquoteright}Total Pathogenic Index{\textquoteright}, calculated from the number of parasites of each species present in the total burden, was higher in FW than C sheep (3.8 vs 1.5, p<0.005). The regression coefficient relating FEC to worm burden was larger in FW than C sheep (0.35 vs 0.05 eggs per g faeces/worm, p<0.01). Levels of mucosal mast cells did not differ significantly between lines, but were inversely related to number of worms in FW sheep. There was no such relationship in C sheep. It is concluded that while the large differences in FEC between lines overestimates the difference in total worm burden, FW sheep do carry significantly more worms of the abomasal species H. contortus and O. circumcincta than C sheep. FW sheep are able to maintain superior wool production in spite of this potentially more pathogenic worm burden. The mucosal mast cell response to parasitic infection also appears to have been changed by selection. }, issn = {1176-5283}, author = {Purchas RW and Thomson NA and Waghorn GC and Death AF} } @conference {40458, title = {Effect of distance walked on dairy production and milk quality}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {69-72}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A universal goal of extension agents is the attainment of voluntary behavioural changes in clients. Behaviour change occurs through the process of learning new skills. There are two distinct components to learning; grasping information through conceptualisation or experience, and: transformation of information into knowledge, through reflection or experimentation. Individual clients can be grouped into one of four distinct learning styles depending on the way they grasp information and transform it into knowledge. This paper draws upon findings from a pilot study to estimate cognitive changes occurring in a group farm monitoring programme. The results indentified learning preference and belief differences between expert and farmer roles within the group. It is suggested extension agents can target specific behaviour changes in client{\textquoteright}s by implementing strategies that use learning preference and belief data. Furthermore, it is proposed researchers can enhance levels of technology adoption by presenting research outputs using communication methods compatible with target clients{\textquoteright} preferred learning styles.}, issn = {1176-5283}, author = {Thomson NA and Barnes ML} } @conference {40447, title = {An evaluation of a possible complementary effect of grazing goats with bulls in an intensive bull beef system}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {23-28}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {

A field trial at Flock House over a three year period (July 1989 - March 1992) compared the performance of grazing bulls alone at three stocking rates (3.0,3.7 and 4.5 bulls/ha) with grazing bulls at 3.0 bulls/ha with an increasing stocking rate of goats (3,7, and 13 Angora does/ ha). The respective stocking rates in stock units @/ha) for the six respective treatments from bulls alone at increasing stocking rate to bulls with goats at increasing stocking rate of goats were 15,19,23,18,21, and 26 su/ha respectively. Weaner bulls were brought onto the farmlets in November each year and all rising 2 year bulls were sold off the farmiets over January to April at 18-21 months of age.

Bull growth rates were significantly depressed by increasing the stocking rate of bulls but were unaffected by an increasing stocking rate of does. Bulls in the bull/goat treatment at 26 su/ha grew at a similar rate to bulls alone, stocked at 15 su/ha. Goat performance; kidding, kid fleece weight and doe fleece weight were not affected by goat stocking rate. However at the high doe stocking rate, kid liveweight at\ weaning and doe liveweight (March) was reduced (P\<0.01 and P\<0.05 respectively).\  Stocking rate treatments had little effect on the economic farm surplus (variation between $680/ha for the least profitable $730/ha for the most profitable treatments).\  However with a more buoyant mohai market and a more robust/productive strain of Angora goat ie. the Zimbabwe Angora, it is assumed the bull/goat system would be more profitable than bulls alone.

Although goats were not complementary to bull beef production they were also not competitive with bulls over the stocking rates investigated.

}, issn = {1176-5283}, author = {Thomson NA and Power MT} } @conference {40324, title = {The effect of cow age and management of winter liveweight gain, liveweight at calving and subsequent effects on dairy production in a seasonal supply herd}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {51}, year = {1991}, month = {Jan}, pages = {277-282}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A trial was undertaken in which 11 meat company lamb drafters estimated the GR carcass fatness, hot carcass weight and carcass class on 26 live lambs. In addition the Phillips Fat Displacement Meter (PFDM) was used to estimate GR fatness these live animals. The average hot carcass weight of the lambs was 21.9kg and mean GR on the left and right sides were 14.2mm and 14.5mm respectively. The best two drafter estimates correlated more highly (0.89 and 0.83) than the PFDM (0.81) with lamb carcass GR (mm) on the left sides of these carcasses. On the right sides these two drafters correlations were respectively 0.91 and 0.84 while the PFDM correlation was 0.85. The correlations of the poorest drafter were 0.62 and 0.57 for the left and right sides, respectively. While the best drafters were accurate in ranking live lambs for fatness, in absolute terms all drafters underestimated GR on average by 2.2mm whereas the PFDM underestimated by 1.1mm on the left side and 0.8mm on the right. So for actually drafting lambs for slaughter, the PFDM is less likely to select lambs in the penalty payment ranges, or is more likely to select lambs before they reach these penalty fatness levels than the company drafters. These results highlight the need for drafter training courses with feedback on their results. On average the drafters underestimated carcass weight by 4.0kg. }, issn = {1176-5283}, author = {Thomson NA and Barnes ML and Prestidge R} } @conference {40122, title = {Management for milkfat or protein, does it differ?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {48}, year = {1988}, month = {Jan}, pages = {225-230}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The utilisation of a supplementary energy supply and its effects on urea metabolism and rumen function were examined in sheep fed indoors on fresh lucerne (Medicago sativa cv. Rere) (N content, 34 g/kg DM). Sheep were fed hourly and infused intraruminally with either water (1200 ml/d; n=5; N intake, 33.0 g/d) or similar volume containing sucrose (160 g/d; n=4; N intake, 32.1 g/d). The additional energy resulted in a lower rumen fluid ammonia concentration (264 v 142 mg N/l). In a comparable experiment with sheep fed chopped lucerne hay, continuous infusion of sucrose also resulted in increased propionic acid levels in the rumen which was reflected in an increase in plasma glucose production (113 v 188 g/d) in the infused group. The results suggest that supplementary fermentable carbohydrate is effective in improving the efficiency of utilisation of pasture protein. The effect appears to be 2-fold: excess ammonia-N i9s captured as microbial protein which is then available for enzymic digestion in the lower gut; the additional fermentative activity increases propionate production which in turn is available for glucose production, thus sparing amino acids for tissue protein utilisation.}, issn = {1176-5283}, author = {Thomson NA} } @conference {40010, title = {Preliminary investigation into factors affecting lamb growth from birth to weaning on Taranaki hill country}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {46}, year = {1986}, month = {Jan}, pages = {139-144}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The aim of the present study was to examine the influence of the ram on plasma FSH concentrations in progesterone-primed Romney ewes which were: (1) anoestrous; (2) devoid of ovaries; (3) or anoestrous but induced to ovulate by a pulsatile injection regimen of luteinising hormone (LH). The results showed that there was an abrupt fall in the mean FSH levels in anoestrous or LH-pulsed ewes at 1 hour after ram introduction and that this level of suppression (~40\%) was maintained for ~22 hours in anoestrous ewes and for 12 hours in LH-pulsed ewes. Also, an FSH reduction (~20\%) was observed in the ovariectomised ewes. In the anoestrous ewes, the FSH changes were observed without any associated oestrous or ovulatory behaviour. In the LH-pulsed group, all ewes showed oestrus and 75\% produced normal corpora lutea. Collectively, the evidence suggests that when attempts are made to achieve fertile matings in hormone-treated anoestrous ewes, there may be advantages in delaying ram introduction until ~24 hours after progesterone withdrawal.}, issn = {1176-5283}, author = {Thomson NA and Mace MJ and Wright LA and Bishell SM} } @conference {39961, title = {A preliminary investigation into factors affecting lamb growth on Taranaki hill country}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {45}, year = {1985}, month = {Jan}, pages = {137-140}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Lactating or non-lactating Coopworth ewe hoggets were offered low, medium or high herbage allowances for 8 weeks during lactation in each of 2 years. Herbage allowance had only a small effect on the penalty of a hogget lactation. Relative to their non-lactating counterparts, the hoggets that had lactated were on average 12.8 kg lighter at weaning and had a 0.29 kg lower clean fleece weight. These penalties are larger than those reported in other New Zealand studies in which the lactating hoggets were preferentially fed. The lambs reared by the hoggets had live-weight gains typical of those observed in twin lambs reared by adult ewes.}, issn = {1176-5283}, author = {Thomson NA and Brown WB and Mace MJ} } @conference {39885, title = {Herbage allowance, pasture quality and milkfat production as affected by stocking rate and conservation policy}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {44}, year = {1984}, month = {Jan}, pages = {67-70}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Four cows were fitted with unilateral temporary cannulae to both parotid and mandibular glands in an experiment designed to determine which salivary proteins were secreted by these glands. Parasympathomimetic stimulation produced a large salivary flow from the parotid gland (50.8 ml/min) with a relatively low protein concentration. Mandibular flow rates were lower, but the protein concentration was high giving a total protein of 1.3 mg/min. Sympathomimetic stimulation, during a parasympathomimetic booster, reduced the flow rates from both glands but increased the total protein output 7-fold from the parotid and 8-fold from the mandibular gland. Band 4 was the major protein secreted by the parotid gland while bands 3, 7 and 8 were the major bands secreted by the mandibular gland.}, issn = {1176-5283}, author = {Thomson NA and Lagan JF and McCallum DA} } @conference {39716, title = {A comparison of lucerne and grass-clover pastures for dairying in South Taranaki - Brief Communication}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {41}, year = {1981}, month = {Jan}, pages = {88-89}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Thomson NA and Lagan JF} } @conference {39521, title = {Effect of lambing date on the utilization of grass/clover and lucerne pastures during mating}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {36}, year = {1976}, month = {Jan}, pages = {184-189}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Thomson NA and Jagusch KT} } @conference {39359, title = {Review of Field Research Section Fertilizer x Stocking Rate Grazing Trials in New Zealand}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {32}, year = {1972}, month = {Jan}, pages = {64-76}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Joblin ADH and Blackmore LW and Bircham JS and Cossens GG and Cumberland GLB and O{\textquoteright}Connor MB and Thomson NA and Smith RG and Wright DF} }