@article {3672, title = {Changes in live weight and fleece characteristics during the lifetime of three breeds of New Zealand feral sheep that differ in fleece type}, journal = {New Zealand Journal of Animal Science and Production}, volume = {80}, year = {2020}, month = {09/2020}, pages = {117-123}, address = {Online}, abstract = {Live weight after joining and nine fleece characteristics were recorded throughout the lifetime of flocks of Hokonui, Campbell Island and Raglan sheep grazing at Whatawhata and Winchmore Research Centres between 1991 and 2004. The wool characteristics were measured in 585 individual wool samples collected at shearing from 90 breeding ewes sampled between one year of age and up to 12 years of age. Data on live weight, fleece weight, staple length, mean and variability of fibre diameter, fibre curvature, crimping and core bulk were analysed after adjustment for effects of grazing location and reproductive performance during the previous year. The three flocks differed in all measured characteristics, with all except live weight, mean fibre curvature and core bulk exhibiting a significant flock by age interaction. Live weight attained a maximum at six years of age, while greasy fleece weight and staple length decreased after two years of age. Core bulk decreased after three years of age. Fibre curvature decreased and time to form a crimp increased throughout the sheep{\textquoteright}s life. Fibre diameter variability between and along fibres showed a variable age response between flocks. The three feral flocks exhibited a different age response to continuously farmed breeds. Keywords: fleece characteristics; age effects; Hokonui; Campbell Island; Raglan}, issn = {1176-5283}, author = {Sumner RMW and Scobie DR and O{\textquoteright}Connell D and Henderson HV} } @conference {89244, title = {Association of the KRT33A (formerly KRT1.2) gene with live-weight and wool characteristics in yearing Perendale sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {73}, year = {2013}, month = {Jan}, pages = {158-164}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {

DNA samples from 691 mixed-sex Perendale sheep, born between 1998 and 2001, were typed for variation in the KRT33A gene using polymerasechain reaction - single-strand conformational polymorphism. The sheep were the progeny of two linesselected for either decreased (L), or increased (H) core bulk at yearling shearing, crosses between the lines and back-crosses. Five variants (A{\textendash}E) of KRT33Awere identified with a frequency of 0.07, 0.04, 0.07, 0.35 and 0.47, respectively. The proportion of Adecreased and Bincreased, with a progressive increase incrimp frequency, fibre curvature and core bulk and a progressive decrease infleece weight, staple length and washing yield with each step-wise increase in the proportion of genes derived fromthe H line. An effect of the presence of Aon the measured wool characteristics was found, but was less than the effect with direct selection for core bulk. There was no consistent effect on body growth. While none of the variants of KRT33Awere strongly predictive of variation in core bulk, other genes on Chromosome 11 may be implicated in the differential expression of characteristics associated withcore bulk.

}, issn = {1176-5283}, author = {Sumner RMW and Forrest RHJ and Zhou H and Henderson HV and Hickford JGH} } @conference {89239, title = {Relative performance of three strains of fine-woolled Merino sheep farmed on Waikato hill country}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {73}, year = {2013}, month = {Jan}, pages = {136-142}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {

Flocks of Saxon (ex Tokanui Research Station), Merryville (ex Tara Hills Research Station) and Fine Peppin (ex Tokanui Research Station) Merino sheep were established at the Whatawhata Research Centre to investigate their relative productivity under North Island hill country conditions. Production data were collected for five years. The Fine Peppin ewes had a higher reproductive rate (0.1 {\textpm} 0.05 (standard error of difference) lambs weaned/ewe joined) with a higher lamb birth weight (0.37 {\textpm} 0.08 kg), lamb weaning weight (1.9 {\textpm} 0.4 kg) and yearling weight (3.5 {\textpm} 0.6 kg), a higher ewe greasy fleece weight (1.2 {\textpm} 0.1 kg) that was longer (7 {\textpm} 2 mm) and coarser (3.0 {\textpm} 0.2 μm) with a greater coefficient of variation of fibre diameter (2.2 {\textpm} 0.4 \%), lower brightness (-1.3 {\textpm} 0.4 CIE Y units) and more yellow (1.1 {\textpm} 0.2 CIE (Y-Z) units) than the Saxon. The Merryville was intermediate between the other two strains for most characteristics. The yearling fleece of each strain exhibited similar trends to the adult fleece. On the basis of the measured performance, and applying wool and lamb price trends between 2007/08 and 2011/12, the differential returns per ewe of the Fine Peppin would be expected to exceed that of the Saxon by $8.80 with the Merryville being intermediate.

}, issn = {1176-5283}, author = {Sumner RMW and Henderson HV} } @conference {78980, title = {Relative performance of Wiltshire and Perendale sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {72}, year = {2012}, month = {Jan}, pages = {28-34}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {

Performance data are reported for flocks of Wiltshire and Perendale sheep grazed together for four years on a North Island hill country property (Whatawhata) and for four years on a South Island breeding/finishing property (Winchmore). Wiltshire ewes were lighter than Perendale ewes post-joining at Whatawhata, and at weaning at Winchmore. Greasy fleece weights of the Wiltshire and Perendale yearlings were 0.8 and 2.2 kg respectively, and 0.5 and 3.3 kg respectively for the ewes. As a result of a confounding effect of fibre shedding between day length and date of shearing, Wiltshire ewes exhibited a linear decrease in harvested fleece weight from the yearling stage whereas Perendale ewes showed a curvilinear age effect, with a maximum fleece weight at three to four years of age. Wiltshire ewes had a significantly lower reproductive rate, and lamb survival than Perendale ewes at both locations, with reproductive rate, fertility and litter size increasing significantly following the transfer of the flocks from Whatawhata to Winchmore. While there was no significant difference in the total weight of lambs weaned by the two breeds at each location, the loss in wool production would be compensated by lower shearing and management costs for Wiltshire sheep that shed completely.

}, issn = {1176-5283}, author = {Sumner RMW and Scobie DR and O{\textquoteright}Connell D and Henderson HV} } @conference {75917, title = {Is there an association between dam live weight and litter structure in a flock of grazing Perendale sheep?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {257-262}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {Observational data from a grazing Perendale flock collected between 1985 and 2002 were analysed to investigate whether there was any association between variation in pasture availability over the summer, as reflected in live weight at joining and/or liveweight change between weaning and the subsequent joining, in association with litters of different sizes and sex structure, and the sex ratio of lambs born during the following spring, under pastoral farming conditions. The flock was managed at Whatawhata Research Centre until 1997 and thereafter at Winchmore Research Station. Data for a total of 3,516 lambs were analysed. Between year variation and variation associated with all the assessed factors, was consistent with chance variation. The proportion of males born was not significantly different from 0.50. Ewe age was significant at Winchmore when adjusted for lambing year, and litter size in both the previous and current lambings and liveweight change of the dam between weaning and joining, with more males born to mature ewes. Three percent more male than female lambs died between birth and weaning at both locations. It is unlikely sheep farmers can consistently influence the sex ratio of their lamb crop through changes in their flock management procedures.}, issn = {1176-5283}, author = {Sumner RMW and Henderson HV and Sheppard AM} } @conference {69497, title = {Genetic and environmental relationships between liveweight change over the summer in Perendale ewes and the lifetime live weight profiles of their progeny}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {70}, year = {2010}, month = {Jun}, pages = {165-170}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {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{\textquoteright}s productivity in the short term.}, issn = {1176-5283}, author = {Sumner RMW and Morris CA and Hickey SM and Sheppard AM} } @conference {60948, title = {Do objective measurements or subjective assessments explain more of the variation in strong wool auction prices?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {69}, year = {2009}, month = {Jun}, pages = {80-84}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {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. }, issn = {1176-5283}, author = {Sumner RMW} } @conference {60949, title = {Realities of clip preparation for strong wool from adult sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {69}, year = {2009}, month = {Jun}, pages = {85-89}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {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. }, issn = {1176-5283}, author = {McDermott AK and Sumner RMW} } @conference {41789, title = {Relative economic value of wool processing parameters for New Zealand strong wool between 2003 and 2007}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {68}, year = {2008}, month = {Jan}, pages = {53-56}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Brisbane, Australia}, abstract = {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 {\textpm} 0.2 c/ kg clean/mm change in barbe length, -1.9 {\textpm} 0.9 c/kg clean/{\`\i}m change in mean fibre diameter, 2.5 {\textpm} 0.5 c/kg clean/CIE Y value change in brightness, -5.0 {\textpm} 0.6 c/kg clean/CIE Y-Z value change in intensity of yellowness and -16.8 {\textpm} 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. }, issn = {1176-5283}, author = {Sumner RMW and McDermott AK and Cox NR} } @conference {41724, title = {Effect of divergent selection for wool bulk on live weight and wool characteristics in Perendale sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {67}, year = {2007}, month = {Jan}, pages = {180-186}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Wanaka}, abstract = {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 {\textpm} standard errors for each of the measured characteristics were; core wool bulk (0.57 {\textpm} 0.03), pre-shear live weight (0.35 {\textpm} 0.04), greasy fleece weight (0.44 {\textpm} 0.04), washing yield (0.42 {\textpm} 0.03), clean fleece weight (0.45 {\textpm} 0.03), staple length (0.54 {\textpm} 0.03), total crimps (0.38 {\textpm} 0.03), crimp frequency (0.46 {\textpm} 0.03), mean fibre diameter (0.62 {\textpm} 0.04), fibre diameter variation (0.58 {\textpm} 0.04) and mean fibre curvature (0.67 {\textpm} 0.04). At the end of the trial, line divergence (H {\textendash} 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 {\textendash}0.8 standard deviation units respectively, and lesser changes in other traits.}, issn = {1176-5283}, author = {Sumner RMW and Clarke JN and Cullen NG} } @conference {41885, title = {Economic consequences for sheep farmers from using genetic technologies}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {149-154}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Agricultural commodity products experience marked price trends over time. In the 1980s the balance between returns to growers, before deducting costs, from meat and wool was 46/54. The ratio has now shifted to 83/17. Price increases of the magnitude currently required to redress this imbalance for wool growers may be achievable through genomic technologies. Such technologies could create a demand for biological components extractable from a proportion of the national clip, permit the development of novel fibre types and significantly reduce wool harvesting and husbandry costs. The economic benefits to sheep owners through changing wool characteristics such as fibre diameter or crimp are limited by existing high volume, low profit margin value chains. New technologies which improve wool characteristics and value should be complemented where possible by direct supply relationships between producers and end-users in order to justify their development and to sustain price premiums.}, issn = {1176-5283}, author = {Sumner RMW and Davison RM} } @conference {41894, title = {Effect on fleece weight of combining genes from four flocks independently selected for increased fleece weight}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {195-199}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {This study investigated whether heterosis was present when crossing sheep from four closed Romney flocks selected for increased fleece weight. Three of the flocks had been developed by AgResearch (C, W and H) and one by Massey University (M). Each ewe was joined with a single ram according to a diallel design to generate single-line, two-line and four-line cross progeny. The trial ran from 1988 to 1996 with 599 records available for analysis. In rank order, the mean ({\textpm} standard error of mean) greasy yearling fleece weight (kg), adjusted for year, sex, pre-shearing live weight and days of wool growth was W (3.41 {\textpm} 0.08), H (3.39 {\textpm} 0.12), C (3.31 {\textpm} 0.10), M (3.10 {\textpm} 0.15) for the "single-line" groups, WC (3.40 {\textpm} 0.09), MW (3.36 {\textpm} 0.10), CH (3.24 {\textpm} 0.08), WH (3.16 {\textpm} 0.11), MH (3.14 {\textpm} 0.11), MC (3.14 {\textpm} 0.10) for the "two-line" crosses and 3.26 {\textpm} 0.06 for the four-line cross. Combining sheep from two or more flocks independently selected for increased fleece weight resulted, on average, in no heterosis in wool production among resultant progeny. }, issn = {1176-5283}, author = {Sumner RMW and Clarke JN and Blair HT and Cullen NG and Henderson HV} } @conference {41884, title = {Environmental and physiological mechanisms underlying wool growth rhythms in New Zealand coarse wool sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {144-148}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Coarse-woolled sheep breeds such as the Romney exhibit a pronounced annual cycle of wool growth with concomitant changes in fibre length growth rate and mean fibre diameter with maxima in summer and minima in winter. This cycle, which is entrained by seasonal changes in daylength via changes in circulating prolactin, parallels wool growth rate in Romney sheep. The cycle is also influenced by complex interactions between nutrient supply and hormones associated with reproductive status. A marked depression in wool production occurs during early pregnancy, which cannot be completely ameliorated by supplementary feeding, and does not directly involve prolactin. Additionally, in ewes, experimental and pharmacological increases and decreases in the prolactin concentration at parturition and during lactation are associated with increases and decreases, respectively, in spring and summer wool growth rate. A greater appreciation of the different mechanisms that temporally influence the wool growth cycle represents a potential means to change fleece characteristics. The development of sheep genotypes with a reduced amplitude of their wool growth cycle would significantly contribute to a reduction in fibre variability that can affect processing performance. }, issn = {1176-5283}, author = {Kendall PE and Sumner RMW and Pearson AJ} } @conference {41883, title = {Gene markers for wool fibre traits}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {139-144}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Selective breeding has been used for thousands of years to improve the quality and weight of wool, but surprisingly there is still a large amount of genetic variation present at the loci involved in the {\textquotedblleft}blueprint{\textquotedblright} for wool synthesis. This genetic heterogeneity results in considerable variation within, and between individual fleeces. This has both positive and negative implications. Where a wool processor requires uniformity in raw stock, both to gain efficiency in processing and to make a product to specification, it has a negative effect. Where specific traits convey unique properties it opens up opportunities for differentiated products. Markers for genes or knowledge of individual gene effects may be useful for identifying sheep with desirable wool traits that are difficult or expensive to measure under field conditions. The discovery of genetic variation in valuable fibre traits could allow the development of gene-marker tests which would assist breeding for more consistent wool.}, issn = {1176-5283}, author = {Abbott JKR and Hickford JGH and Sumner RMW} } @conference {41878, title = {Options for change within the wool supply chain}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {113-119}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Supply chains are the channels along which products flow from producer to processors and manufacturers, distributors and retailers until final consumers purchase them. The businesses along the chain are linked through the transactions between them and the information that they share. Wool is an inherently variable product that cannot be adapted quickly to changes in processor{\textquoteright}s requirements. As such it is a weak competitor in a section of the global textile marketplace dominated by synthetic textiles derived from petrochemicals. Nevertheless, wool has unique functional advantages over most synthetic fibres. Efficient supply chains are dependent on effective relationships between stakeholders. Reduction of costs incurred along the supply chain requires investment in horizontal and/or vertical relationships to improve information transfer between stakeholders, or to benefit from economies of scale and/or scope. Improved information transfer strengthens stakeholder confidence enabling the development of innovative business initiatives. }, issn = {1176-5283}, author = {McDermott AK and Sumner RMW and Scobie DR} } @conference {41604, title = {Presidential Address 2005: Animal production - the bridge between animals on the farm and the consumer}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {1-3}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {The development of man from caveman to the sophisticated being that he is today has been dependent on us using the animals and plants surrounding us as a source of food, warmth and shelter. As we have developed so we have mastered the management of these resources to make life more comfortable. In managing these resources we have developed ways and means of manipulating animals and plants in various ways to produce special products. }, issn = {1176-5283}, author = {Sumner RMW} } @conference {41855, title = {Re: Relation between sweating and wool yellowing in Merino and Romney sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {378}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {

In the original printed version of this paper, incorrect labelling of some of the axes occurred in two of the figures. Corrected versions are shown below. The authors regret this error.

}, issn = {1176-5283}, author = {Sumner RMW} } @conference {41567, title = {Relation between skin structure and wool yellowing in Merino and Romney sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {197-202}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Five adult Merino and five adult Romney ewes were skin sampled on the back, midside and belly regions of the body following a study measuring the relationship between rate of sweat secretion and wool yellowing under various controlled environmental conditions. Densities of primary follicles, secondary follicles, sweat (sudoriferous) glands and sebaceous glands, as well as dimensions of the sweat and the sebaceous glands were measured. The density of secondary follicles was negatively related to wool yellowing and there was a weaker positive relationship between the density of primary follicles and wool yellowing. Underlying these relationships were associations of measurements suggesting sebaceous gland output restricted wool yellowing while sweat gland output encouraged wool yellowing. In addition, large sweat glands were related to increased sweat secretion rate. The results of this study suggest there may be two potential avenues to minimise fleece discolouration while the wool is growing on the sheep; either increasing sebum production or reducing sweat production. KEYWORDS: Romney; Merino; wool yellowing; wool follicles; sweat glands; sweat; sebaceous glands. }, issn = {1176-5283}, author = {Sumner RMW and Craven AJ} } @conference {41566, title = {Relationship of mean fibre diameter and time of shearing with wool yellowing in Merino sheep farmed under North Island conditions}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {191-196}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Approximately 200 adult Merino ewes at each of four sites in New Zealand, near Hamilton (Whatawhata), near Rotorua, near Havelock North (Poukawa) and near Wanganui were shorn once-yearly at five different times over two years. Groups of approximately 40 ewes in each flock were shorn pre mating (March), post mating (May), pre lambing (July) with lambs-at-foot (October) or at weaning (December/January). Midside fleece samples were collected before shearing for measurement of fibre diameter. At shearing each fleece was weighed and skirted. The skirted fleece and skirtings were weighed and core bored for measurement of wool yellowness. The between flock and between shearing time ranking for increasing wool yellowness was Wanganui, Poukawa, Rotorua, Whatawhata and lambs-at-foot, pre lambing, weaning and post mating, pre mating respectively for both the unskirted and skirted fleeces. There was a significant positive relationship between mean fibre diameter and wool yellowing with no difference in the slope of the relationship between flocks or between shearing time treatments. These trends align with finer-woolled Merino sheep having more sebaceous glands, the secretion from which appeared to protect growing wool fibres from the action of components in sweat secreted in response to warm moist atmospheric conditions. The optimal shearing time to produce the whitest wool was spring. KEYWORDS: Merino; wool yellowing; fibre diameter; shearing time. }, issn = {1176-5283}, author = {Sumner RMW} } @conference {41522, title = {Relation between sweating and wool yellowing in Merino and Romney sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {64}, year = {2004}, month = {Jan}, pages = {286-292}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Five adult Merino and five adult Romney ewes with 7 months growth of fleece were subjected to nine different environmental challenges in a climate controlled room on consecutive days where the temperature humidity index (THI) was varied from 74.2 to 91.3 for up to 7 h at each exposure. Secretions were collected from glands in the skin on the back, midside and belly regions of each sheep. The sheep were shorn 5 months later. There was a significantly curvilinear increase in total skin gland output and the rate of secretion of titratable alkalinity and potassium ions with increasing THI. Romney sheep had a higher secretion rate than Merino sheep with no significant site effect. The rate of secretion of titratable alkalinity and potassium ions by the skin glands were both strongly related to tristimulus (Y-Z) of the fleece at shearing (base yellow) (R2 = 0.93, 0.92) and after incubation of the wool sample at 40{\textdegree}C and 100\%RH for 6 d (challenge yellow) (R2 = 0.96, 0.95). These data indicate a particularly strong relationship between the rate of secretion of titratable alkalinity and potassium ions by the skin glands and the later propensity of the fleece to develop a yellow discolouration. }, issn = {1176-5283}, author = {Sumner RMW and Ashby MG and Craven AJ} } @conference {41428, title = {Wool yellowing and pH within Merino and Romney fleeces}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {63}, year = {2003}, month = {Jan}, pages = {155-159}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Queenstown}, abstract = {Fleece samples were taken from the back, side and belly of three adult ewes in one Merino flock and three adult ewes in one Romney flock in each of six regions of New Zealand (Waikato, Manawatu, Wairarapa, Marlborough, Canterbury, Otago). Each fleece was 12 months growth. These samples were used to compare factors associated with wool yellowing as measured by tristimulus (Y-Z) values. Neither the region of New Zealand where the sheep grazed nor the measured dimensional fleece characteristics, were related to fleece yellowing. The pH of an aqueous extract of greasy wool was strongly related (R2 = 0.93) to tristimulus (Y-Z) (base yellow) at shearing but less strongly related (R2 = 0.70) to tristimulus (Y-Z) after the sample had been incubated at 40{\textdegree}C and 100\% RH for 6 d. Merino samples had a lower tristimulus (Y-Z), both before and after incubation, at a particular pH than Romney samples. Back wool did not increase in yellowness as much during incubation as side or belly wool possibly on account of photo-oxidation following prolonged exposure to sunlight. These data indicate a close relationship between pH of a water soluble component of greasy wool and the extent of wool yellowing that was influenced by sheep breed and body site. }, issn = {1176-5283}, author = {Sumner RMW and Young SR and Upsdell MP} } @conference {41315, title = {Factors associated with yellowing within Romney}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {61-64}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {Four two-year-old Romney ewes born in the Waikato and four two-year-old Romney ewes born in Canterbury that had been grazed together in the Waikato for 12 months, were used to investigate aspects of yellowing in wool samples grown on the mid-back, mid-side and mid-belly. Two sheep in each sub-group had a history of having a relatively high and two sheep a relatively low, propensity for their fleece to turn yellow during the previous year. Dimensional fibre characteristics, with the exception of staple length, were not significantly different between body sites, between the propensity groups or between birth farm groups. Wool was shorter on the belly than on the other two sites. Incubating greasy sub-samples of each fleece at 40{\textdegree}C and 100\% relative humidity for 6 d induced a curvilinear increase in yellowness with the CIE Y - Z value approaching an asymptote. A significant amount of the variation in yellowing was explained by the concentration of K, Ca and possibly Na, elements secreted in the suint. These data suggest that the propensity of a fleece to turn yellow is not related to fleece architecture or the elemental composition of the fibres, but may have a physiological basis possibly related to sweating behaviour. }, issn = {1176-5283}, author = {Sumner RMW} } @conference {41262, title = {Age effects and interrelationships between wool characteristics of genotypes used to develop GrowBulk sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {61}, year = {2001}, month = {Jan}, pages = {100-103}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Groups of 10 ewes of four breeds (Romney, Dorset cross Romney, Texel cross Romney, (Dorset x Romney) cross (Texel x Romney) born in two years (1994, 1995) were used to investigate the changes of wool characteristics with increasing age. Each ewe was wool sampled at hogget shearing in October and at each subsequent annual shearing in July until 1999. Romney fleeces had higher clean fleece weight, lower core bulk, longer staple length, less fibre curvature and lower crimp frequency. All genotypes exhibited similar ageing patterns for each measured wool characteristic except fibre diameter variability. Days to form a crimp increased, staple length and core bulk did not change and fibre curvature and crimp frequency decreased with increasing age. Clean fleece weight and fibre diameter increased to a plateau between 2 and 4 years of age before declining. The repeatability of all individual characteristics decreased with increasing age. There were no consistent differences in the relationship between core bulk and a combination of fibre curvature and fibre diameter across genotypes within age groups. Crossing Dorset and Texel rams over Romney ewes to generate a specialty high wool bulk composite genotype did not influence the age trends and interrelationships between individual wool characteristics inherent in the base Romney flock. }, issn = {1176-5283}, author = {Sumner RMW and Upsdell MP} } @conference {41185, title = {Effect of sample preparation method on the validity of an early-life predictor of hogget wool bulk in genotypes used to develop GrowBulk sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {60}, year = {2000}, month = {Jan}, pages = {155-158}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Selection for wool bulk is normally undertaken in yearlings. In this study, a mixed-sex group of 170 GrowBulk sheep were wool sampled at 6 and 12 months of age. Measurements of fibre curvature and fibre diameter following degreasing a wool sample taken at 6 months of age with either water or solvent, explained 69\% and 67\% respectively of the variation in core bulk at 12 months of age. A combination of fibre curvature and fibre diameter measured following degreasing by either method was equally effective in predicting core bulk at 12 months of age. Precision of the predicted core bulk values was equivalent to direct core bulk measurement. Early-life prediction of core bulk from measurements of fibre curvature and fibre diameter taken close to the skin using consistent sample preparation methods, is a low-cost objective procedure to rank sheep for culling young sheep on wool bulk. }, issn = {1176-5283}, author = {Sumner RMW} } @conference {41188, title = {Variation of fibre and follicle characteristics related to wool bulk over the body of Perendale ewes: Implications for measurement of wool bulk}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {60}, year = {2000}, month = {Jan}, pages = {166-170}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Wool samples were collected prior to shearing in two consecutive years from 8 sites over the body of six adult Perendale ewes differing in wool bulk. A skin sample was collected from the same sites in the second year. Fibre curvature and fibre diameter explained between 67 and 94\% the variation in core bulk at the different sites. No measured characteristics significantly reduced the unexplained variance across all sites. Intercepts for the relationship between fibre curvature and fibre diameter with core bulk at each site were significantly different but less than the confidence limits associated with core bulk measurement. There were no significant differences in the slopes of the same relationships across the eight sites. Use of a pooled relationship to predict bulk from fibre curvature and fibre diameter is a least-cost option to describe the bulk of a fleece. }, issn = {1176-5283}, author = {Sumner RMW and Craven AJ} } @conference {41067, title = {Development of fibre and follicle characteristics related to wool bulk in hoggets of genotypes used to develop GrowBulk sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {59}, year = {1999}, month = {Jan}, pages = {39-42}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Wool fibre and follicle development was monitored in 40 hoggets born in 1996 comprising sex-balanced groups of Romney (R), Dorset x Romney (DR), Texel x Romney (TR) and DR x TR and TR x DR (DTR) sheep between 3 and 12 months of age. There was a significant curvilinear pattern of development for fibre curvature and follicle curvature for the DR, TR and DTR groups whereas values for the R group did not change significantly with time. Fibre diameter was not significantly different between the groups. A combination of fibre curvature and fibre diameter explained approximately 70\% of the variation in core bulk within all genotypes at hogget shearing for samples taken at points in time during growth of the fleece. The combination of fibre curvature and fibre diameter is a useful predictor of adult wool bulk to assist breeders of GrowBulk sheep. }, issn = {1176-5283}, author = {Sumner RMW} } @conference {41060, title = {Genetic effects in GrowBulk sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {59}, year = {1999}, month = {Jan}, pages = {14-16}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {GrowBulk sheep are a strain of long-wool type sheep growing high bulk wool developed by introgressing high-bulk genes from Texel and Dorset rams into Romney ewes. Progeny selection was planned to minimise decreases in clean fleece weight. Rams have been released to four multiplier flocks. Genetic effects were evaluated in the nucleus and multiplier flocks using a restricted maximum likelihood animal model. Heritability estimates were 0.46{\textpm}0.05 for bulk and 0.30{\textpm}0.05 for clean fleece weight with a genetic correlation of -0.48{\textpm}0.09. The crossbred genotypes represented in the nucleus flock showed a range in average breeding merit for bulk of 27 to 31 cm{\textthreesuperior}/g, their weighted mean genetic superiority over contemporaneous Romneys being 5.3 cm{\textthreesuperior} /g. The first crop of commercial progeny by rams from this flock showed an average genetic superiority in bulk over their dams of approximately 4 cm{\textthreesuperior}/g. Genetic trends indicate that selection has been able to maintain the bulk advantage of the crossbreds while at the same time improving their fleece weight. }, issn = {1176-5283}, author = {Clarke JN and Sumner RMW and Cullen NG} } @conference {41066, title = {Seasonal wool growth patterns and the follicle and fibre characteristics of New Zealand feral sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {59}, year = {1999}, month = {Jan}, pages = {34-38}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Wool follicle and fibre characteristics, and aspects of their seasonality were assessed in feral sheep from the Hokonui Hills (Merino origin), Campbell Island (Merino x long-wool breeds) and Raglan Peninsula (Romney). Live weight, fleece weight, staple length, crimp frequency, fibre diameter, fibre curvature, follicle density and secondary to primary follicle ratio differed between breeds, reflecting their breed origins. Mean clean fleece weights of the feral breed groups were approximately half that of their modern counterparts. Factors contributing to the low productivity were reduced staple length and follicle density, and a brief cessation of growth by some follicles during spring. The mean amplitude of rhythms in seasonal wool growth and fibre diameter increased with age, and appear to have converged to similar values, contrasting with their modern breed counterparts. }, issn = {1176-5283}, author = {Pearson AJ and Ashby MG and Sumner RMW and Nixon AJ} } @conference {41048, title = {Seasonality of wool growth in Waikato and Southland of Romney sheep selected for high fleece weight}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {58}, year = {1998}, month = {Jan}, pages = {270-273}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Wool growth rate was estimated for a total of 525 Romney ewes born in 1991 and 1992 between 5 and 28 months of age. Both year born groups contained sheep from three flocks selected over an extended period for increased hogget fleece weight and their respective Control flock. One flock was located in the Waikato, one in Southland and one split between the two locations. Following adjustment for live weight the seasonality of wool growth rate in Southland was significantly greater than in the Waikato reflecting the sensitivity of Romney sheep in recognising small changes in the length of daylight between the two locations. Selection for increased hogget fleece weight resulted in a greater increase in relative wool growth rate during the winter than during the summer. }, issn = {1176-5283}, author = {Sumner RMW and Wuliji T and Dobbie JL and Andrews RN and Upsdell MP} } @conference {40889, title = {Changes in fibre and follicle characteristics related to wool bulk during the lifetime of Perendale ewes.}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {57}, year = {1997}, month = {Jan}, pages = {65-69}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Wool and skin samples were collected annually at hogget shearing in October and thereafter in July for a further four shearings, from a total of 32 Perendale ewes born in 1990 and 1991 within lines selected for or against wool bulk. Time to form a crimp, follicle curvature and the proportion of para-meso cortical cells, increased towards an asymptote with increasing age. Proportion of fibres with a bilateral arrangement of cortical cells was maximal at 2 years of age and clean fleece weight, staple length and fibre diameter were maximal at 3 years of age. Fibre curvature decreased linearly, crimp frequency and follicle length decreased curvilinearly but wool bulk did not change with increasing age. The repeatability of individual characteristics decreased with increasing age. There was no significant difference in the relationship between core bulk and a combination of fibre curvature, fibre diameter and fibre diameter variation within each age group. }, issn = {1176-5283}, author = {Sumner RMW and Dick JL} } @conference {40888, title = {Seasonal changes in fibre and follicle characteristics related to wool bulk in Perendale ewes.}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {57}, year = {1997}, month = {Jan}, pages = {61-64}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Wool bulk is one of six key characteristics that describe processing performance and the final potential of wool products and is largely influenced by fibre crimp and fibre diameter. Measurements of seasonal variation in wool growth, and fibre and follicle characteristics associated with wool bulk were made over 19 months in Perendale ewes within lines selected for or against wool bulk to assess their potential impact on processing performance. Wool growth rate, mean fibre diameter, mean follicle depth and follicle activity displayed a minimum value in July and a maximum in December-January. Mean fibre curvature and follicle curvature grade had an opposing seasonal trend with a maximum in winter and a minimum in summer. The opposing seasonal cycles for fibre curvature and fibre diameter, compensated each other across seasons with no change in the expression of wool bulk throughout the year. }, issn = {1176-5283}, author = {Dick JL and Sumner RMW} } @conference {40844, title = {Development of fibre and follicle characteristics related to wool bulk in Perendale sheep over the first year of life}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {314-318}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The pattern of wool fibre and follicle development was monitored for 20 Perendale lambs from lines selected for or against wool bulk. There was no significant difference in characteristics associated with wool bulk between selection lines at birth. These characteristics followed a curvilinear pattern of development with most of the change taking place between birth and 14 weeks of age then reaching a plateau by 35 weeks. The different rate of developmental change for each bulk line meant that by 14 weeks the high line had a greater follicle curvature grade, shorter follicle length, shallower follicle depth, more para-meso cortex and a higher fibre curvature. Together fibre curvature, fibre diameter and fibre diameter standard deviation explained around 70\% of the variation in hogget wool bulk from 25 weeks of age. From these results it is suggested that the potential of a sheep to produce high bulk wool can be assessed using fibre curvature and fibre diameter from 6 months of age which allows hogget mating and/or early culling to be practised.}, issn = {1176-5283}, author = {Dick JL and Sumner RMW} } @conference {40847, title = {Effect of lamb shearing on fine wool Merino hogget performance}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {328-331}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The effect on hogget productivity and wool processing performance of shearing Merinos for the first time as lambs was investigated. A flock of 200 fine wool Merino lambs were randomly separated into two lines. One line was shorn as lambs in late summer and both lines were shorn the following spring as hoggets. There were no differences in live weight at hogget shearing or in flystrike incidence and internal parasite levels. Total wool production was greater from the twice shorn hoggets compared to those shorn only once, with the hoggets shorn twice producing about 0.4 kg more wool. However the differences in hogget wool quality, processing and product performance when lamb wool was removed and the extra wool production did not cover the discounted wool values due to shorter wool staple length and the extra costs of shearing. At current price relativities justification for first shearing Merinos as lambs must relate to management advantages pertaining to individual properties. }, issn = {1176-5283}, author = {Newman S-AN and Maddever DC and Sumner RMW} } @conference {40846, title = {Effect of wool length and season of shearing on the propensity of Romney, Coopworth and Perendale wool to yellow}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {324-327}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Propensity of wool to yellow is defined as its yellowness after incubation for 14 days at 40 C and 100\% relative humidity. It was determined for mid-side wool samples from Romney, Coopworth and Perendale ewes shorn in summer and/or winter. All samples had a high propensity to yellow (mean Y-Z after challenge 13.0 SD 3.2). The breed ranking from lowest to highest was Perendale, Romney and Coopworth (12.4, 13.1, 13.6, respectively; SED 0.2). Wool shorn in winter was less susceptible to yellowing than wool shorn in summer (11.7 vs 14.4; SED 0.26) and short wool was less susceptible than long wool (12.0 vs 14.1; SED 0.26). There was a highly significant interaction between wool length and time of shearing. Propensity to yellow of wool sampled at hogget shearing was not a significant predictor of propensity to yellow of the adult fleece wool. The measurement was repeatable between some, but not all, successive shearings of adult ewes. This suggests that the method used may be useful in selecting adults to reduce yellowness by breeding.}, issn = {1176-5283}, author = {Reid TC and Sumner RMW and Sedcole JR and Botica KJ} } @conference {40664, title = {Differences in propensity of wool to develop yellow discolouration in flocks of Perendale sheep selected for and against}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {55}, year = {1995}, month = {Jan}, pages = {46-49}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {CONFIRM is a recently developed test kit for verifying pregnancy in dairy cows on the basis of the concentration of oestrone sulphate (OS) measured in a milk sample taken at least 120 days after mating/insemination. In this study, the performance of CONFIRM was evaluated using milk samples from non-pregnant cows returning a }, issn = {1176-5283}, author = {Reid TC and Botica KJ and Sumner RMW} } @conference {40713, title = {Effect of control of internal parasitism on productivity of Merino breeding ewes}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {55}, year = {1995}, month = {Jan}, pages = {205-208}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Sumner RMW and Watson TG and Hosking BC} } @conference {40659, title = {The relationship between cortical structure and fibre diameter in primary and secondary wool fibres of yearling Perendale sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {55}, year = {1995}, month = {Jan}, pages = {31-34}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The effects on bloat of herbage mass and of removing Poa from pasture was investigated. Twelve paddocks were paired on pasture composition in autumn and Poa seedlings were removed from one paddock in each pair. Each paddock was halved and two levels of herbage mass were established. The resulting treatments, high herbage mass with Poa (H+P), high mass without Poa (H-P), low mass with Poa (L+P), and low mass without Poa (L-P), were grazed by four groups of six cows of high susceptibility to bloat over four 12-day periods in spring. Herbage mass was 814 kg DM higher (P<0.001) before grazing and 518 kg DM/ha higher (P<0.001) after grazing on H versus L.Poa content (\% DM) was higher and white clover in +P compared to -P (Poa 11 and 2\%, P<0.001; clover 16 and 26\%, P<0.001). The average bloat score was highest on L-P and least on H+P and was 2.4 times greater on L than H and 5.5 times greater on -P than +P. Results indicated that bloat could be manipulated by altering herbage mass, but any effect on bloat of Poa was confounded with changes in white clover content. }, issn = {1176-5283}, author = {Dick JL and Sumner RMW} } @conference {40590, title = {Repeatability of seasonal wool growth in Merino Sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {163-166}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Wool samples were clipped from the midside of 27 Merino rams and 33 unmated Merino ewes born in 1990 at 4 or 8 weekly intervals, depending on the season, between July 1991 and January 1994. Wool growth rat and mean fibre diameter were measured. Both wool growth rate and mean fibre diameter exhibited seasonal growth cycles which were synchronous. The rhythm of the seasonal cycle for each characteristic was calculated as:- Rhythm (\%) = (Max-Min) / ((Max+Min) / 2) x 100 The rhythm for wool growth rate exceeded that for mean fibre diameter while the rhythms for both characteristics increased significantly between the first and second year but not between the second and third years. Although wool growth rate and mean fibre diameter were strongly correlated between adjacent clipping periods, the derived rhythm estimates for both characteristics were only weakly correlated between years. Adjustment of the rhythm estimates for liveweight change during the same period significantly improved between sheep repeatability of the seasonality estimates. These data indicate that a significant proportion of the variation in both wool growth rate and mean fibre diameter was, after adjustment for liveweight change, associated with permanent phenotypic differences among the sheep in the rhythm of their seasonal wool growth cycle. }, issn = {1176-5283}, author = {Sumner RMW and Clarke JN and Pearson AJ and Speedy PM} } @conference {40529, title = {Plasma prolactin in Romney sheep selected for hogget fleece weight}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {371-376}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Seventy nine mature, alpacas were scanned every 10-14 days using real time ultrasonography to visualise the foetus. There was a 24\% foetal loss between days 21-30 of gestation and parturition, with the maximum loss occurring between days 21-30 and days 31-40 of gestation. There was a 5\% loss of foetuses after day 100 of gestation.}, issn = {1176-5283}, author = {Clarke JN and Pearson AJ and Sumner RMW and Johnson DL and Dobbie JL and Wildermoth JE and Wrigglesworth AL} } @conference {40514, title = {Relationships between loose wool bulk and follicle and fibre characteristics in yearling Perendale sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {307-310}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Progeny test mating was carried out for 7 high fleece weight (HFW) and 5 random control (RC) sires from the Woodlands breeding flocks in 1987, and for a 4 HFW sires in 1988. In 1990, 8 of the surviving HFW sires were backcross mated to their daughters (born in 1987 and 1988). There was no evidence for any of these sires being heterozygous, or for any of the sires involved in the backcross being homozygous, for a major gene which affects either fleece weight or liveweight.}, issn = {1176-5283}, author = {Sumner RMW and Stobart RH and Johnson DL} } @conference {40418, title = {Comparative performance of ewes shorn either once-yearly or 3 times in 2 years}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {52}, year = {1992}, month = {Jan}, pages = {225-228}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The determinants of wool production per unit area of skin are reviewed, and found to be dominated by follicle volume. Evidence is presented to show that follicle cells destined to become fibre cells differentiate into a continuum of cell types rather than discrete populations of medullary, ortho- and paracortical cells as the literature suggests. Fibres of the same dimensions grown by a sheep at one point in time contain differing proportions of these cell types. It is hypothesised that there is a degree of independence between fibre volume and cell differentiation. Medulla formation is explained in terms of competition between follicles for keratin precursors, so that fibre volume exceeds the available volume of keratin. A similar mechanism is proposed for the cortex, where paracortex and mesocortex become less prevalent as total fibre volume increases. It is concluded that a model for fibre formation can be considered in two parts: one which generates fibre volume and another which determines cell type within that volume. }, issn = {1176-5283}, author = {Sumner RMW and Webby RW and Winter RD} } @conference {40338, title = {Bulk and its structural basis: A review}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {51}, year = {1991}, month = {Jan}, pages = {339-346}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A case farm study of a once-bred heifer system on hill country using a spreadsheet simulation model was undertaken. Results of the feed budge and financial data of the once-bred system were compared with bull beef, 18 month heifer finishing and traditional breeding cow policies. The once-bred heifer system generated a gross margin of $48.26/s.u. compared with $42.50/s.u. for a traditional breeding cow breeding system, $31.70/s.u. for the 20 month heifer finishing and $52.80/s.u. for a bull beef system. The once-bred heifer system produced 314 kg carcass/ha, the breeding system cow 197 kg carcass/ha, the 20 month heifer system 354 kg carcass/ha and the bull beef system 433 kg carcass/ha. The major factor affecting the profitability of the once- bred heifer system was schedule price. The best match of animal requirements and pasture growth for the once-bred heifer system was shown to occur for an October calving. This study suggests that sheep and beef farmers with traditional beef cattle policies could increase productivity by adopting a once-bred heifer beef production system. }, issn = {1176-5283}, author = {Stobart RH and Sumner RMW} } @conference {40331, title = {Comparative wool production of Texel, Oxford Down, Finnish Landrace and Romney sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {51}, year = {1991}, month = {Jan}, pages = {303-308}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Two lines of Perendale sheep selected for an against loose wool bulk as yearlings at hogget shearing were established at Whatawhata Research Centre in 1987. Each line consists of approximately 100 mixed age breeding ewes. At ewe hogget shearing in 1989 loose wool bulk of the selection lines differed by 5.2}, issn = {1176-5283}, author = {Dobbie JL and Sumner RMW and Clarke JN and Speedy PM} } @conference {40339, title = {Effect of selecting Perendale hoggets for loose wool bulk on fleece characteristics and wool end-product performance}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {51}, year = {1991}, month = {Jan}, pages = {347-352}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Hoggets from the Massey University fleeceweight-selected (FW) line were previously shown to have lower sulphur (S) concentrations in midside wool than control (C) hoggets at 14 months of age. This study involved two experiments. The first examined wool S concentrations at different body positions in 14-month hoggets and the second examined midside wool S concentration and blood parameters in young lambs. In Experiment 1, 16 FW hoggets and 16 C hoggets were wool sampled at 11 positions over the body. The wool S concentration of FW hoggets was found to be significantly (P<0.01) lower than that of C hoggets (2.77\% vs 2.94\%). Discriminant analysis was used to classify hoggets to their respective lines based on wool S measurements. The combination of sites which most correctly classified the hoggets was the midside plus base of the tail. In the Experiment 2, 40 FW and 40 C lambs were wool sampled on the midside at 28 day intervals from 21 November (1 week before weaning) to 13 February. FW lambs had significantly (P<0.05) lower midside wool S concentrations of urea, but not of creatinine, than C lambs. Results suggest that wool S concentration and plasma urea concentrations may be useful genetic markers for high fleece production but that the ability to discriminate between animals of high versus low genetic merit for fleece weight on the basis of wool S will depend on the sampling position and age of animals. }, issn = {1176-5283}, author = {Sumner RMW and Maddever DC and Clarke JN} } @conference {40346, title = {Wool growth in autumn and spring lambing ewes}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {51}, year = {1991}, month = {Jan}, pages = {383-388}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Four trials in early to mid lactation investigated the effect of supplementation with sodium bicarbonate on milk production from cows grazing pasture. In Trial 1, 3 groups of 14 cows received 0, 100 g or 200 g NaHCO3/cow/day for 28 days. Trial 2 assessed whether any effects of sodium carbonate were due to sodium by comparing no supplement, 200 g NaHCO3/cow/day and 140 g NaC1 with three groups of 20 cows for 28 days. In both trials treatments were administered by drenching at each milking. Trial 3 assessed the importance of method of administration. Treatments of no supplement, 100 g NaHCO3/cow/day by drenching at the morning milking, or 100 g NaHCO3/cow/day in the drinking water were administered to 3 groups of 20 cows, during three 21 day periods according to a latin square design. Trial 4 compared rates of 0, 50, and 100 g NaHCO3 via drinking water with 3 groups of 18 cows for 21 days. In Trial 1 milk yield and protein yield were significantly reduced (P<0.10) by drenching 200g NaHCO3/day, compared to the control cows (14.,7 vs 15.3 kg milk/cow/day). The lower dose rate did not affect milk yield or composition. In Trials 2 and 4, none of the treatments significantly affected milk solid yields. Milk, protein and lactose yields from cows on the trough treatment were higher than those for control and drenched cows in Trial 3. Plasma magnesium was lower in drenched cows than in control or trough treatment cows. }, issn = {1176-5283}, author = {Reid TC and Sumner RMW} } @conference {40266, title = {The effect of early exposure to facial eczema on ewe lifetime production}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {50}, year = {1990}, month = {Jan}, pages = {473-475}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {No abstract supplied }, issn = {1176-5283}, author = {Moore RW and Sumner RMW and Dow BW} } @conference {40237, title = {Effect of shearing once-yearly in January, once-yearly in July or twice-yearly in January and July on ewe performance}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {50}, year = {1990}, month = {Jan}, pages = {329-334}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The major challenges facing the sheep industry are improving animal performance, minimising disease, reducing labour, and being attuned to consumers{\textquoteright} long term needs. Solutions will involve new technology in sheep breeding, biological disease control and novel approaches to reducing labour associated with sheep. Environmental, health and welfare issues are shaping up to be major consumer issues by the 21st century and production techniques will come under closer scrutiny in future. }, issn = {1176-5283}, author = {Sumner RMW and Scott ML} } @conference {40186, title = {Inheritance of loose wool bulk}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {49}, year = {1989}, month = {Jan}, pages = {297-302}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The digestive efficiency of deer, goats and sheep fed on chaffed lucerne hay was compared during summer (S) and winter (W). VFI, rumen pool size and rumen ammonia concentration showed seasonal cycles in red deer, with maximum values in S and minimum values in W, whereas rumen FOR showed lower values in S than in W, especially for particulate matter. Despite an increase in VFI, deer were thus able to maintain DM and fibre digestibility in S, due to simultaneously increasing rumen size and reducing outflow rate. Goats showed higher fibre digestibility relative to sheep, associated with a larger proportion of small particles in rumen digesta. Goats also had the highest rate of rumen ammonia production. Relative to goats and sheep, deer showed very low levels of VFI and rumen pool size in W, emphasising the importance of understanding the factors controlling winter inappetence in red deer, whilst the superior fibre digesting capability of goats suggests they could be most efficiently used to utilise low quality fibrous feeds. }, issn = {1176-5283}, author = {Sumner RMW and Clarke JN and Johnson DL} } @conference {40169, title = {Relative wool production of wethers and ewes of different rearing status}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {49}, year = {1989}, month = {Jan}, pages = {209-214}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Low growth rates in autumn have been described in cattle and sheep in New Zealand and overseas. Comparison of responses in liveweight gain to herbage allowance has shown that animals grazing in autumn grow much more slowly at all allowances than those grazing in spring. When autumn- and spring-born lambs were grazed together, responses in liveweight gain to varying herbage allowance did not depend on their age and/or live weight. There were large differences between the responses of animals grazing in autumn and those grazing in spring. In autumn, animals grazing pasture previously sprayed with high rates of fungicide at high allowances gained weight 28\% faster than those grazing unsprayed pasture - 107.2 v 83.7 g/d. In spring, the use of fungicide on pasture had no significant effect on liveweight gains of lambs.}, issn = {1176-5283}, author = {Sumner RMW and McCall DG} } @conference {40120, title = {Effect of shearing once-yearly in October or twice-yearly in February and October on ewe performance}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {48}, year = {1988}, month = {Jan}, pages = {213-218}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {No abstract supplied}, issn = {1176-5283}, author = {Sumner RMW and Willoughby LD} } @conference {40097, title = {Performance parameters in an autumn lambing ewe flock}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {48}, year = {1988}, month = {Jan}, pages = {91-94}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Among the factors influencing the productivity and profitability of livestock, animal diseases deserve special attention because they diminish the capacity of the animal to achieve its inherent potential level of production, for any given feeding and management regimen. Evidence concerning the nature of the various effects of disease is reviewed, and a hierarchy of effects is defined. The major effects are on protein metabolism and secondarily on energy metabolism. Effects on feed intake are also common, but even diseases which severely ravage the wall of the gastrointestinal tract do not appear as a general rule to significantly reduce feed digestibility. The primary effects of disease on nutrient metabolism flow through to various consequential effects on the productivity of the individual animal, and hence on herd replacement patterns and herd improvement. At least some diseases can continue to affect productivity even after the disease has been cured by treatment. Consequently, the adage that prevention is better than cure has a sound scientific basis. Analyses have shown exceptionally high economic returns from disease prevention, commonly 500 to 1500\% return on invested funds. This is much higher than from curative methods in most cases. As veterinary science evolves from a curative approach towards an economically grounded health management approach, veterinarians will make use of evaluation aids through which the economic and practical implications of alternative actions are compared, so that the action most advantageous to the livestock enterprise can be taken.}, issn = {1176-5283}, author = {Reid TC and Sumner RMW and Wilson LD} } @conference {40065, title = {Effect of different shearing policies on sheep production in Northland}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {47}, year = {1987}, month = {Jan}, pages = {107-110}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Goat farming as a form of livestock farming has developed in New Zealand since the mid 1970{\textquoteright}s. The main cause for this has been the change in the relative economics of the traditional pastoral farming industries of sheep, beef and dairy cows. Farmers have begun to recognise the husbandry and economic aspects of farming goats and have been developing techniques for profitable ventures. Export earnings from goats approached $4 million FOB in 1983-84 but have varied considerably since with the availability of stock for slaughter, dairy goat product market fluctuations, and stock value changes.}, issn = {1176-5283}, author = {Sumner RMW and Armstrong D} } @conference {40023, title = {Implications of objective measurement for sheep management}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {46}, year = {1986}, month = {Jan}, pages = {198-200}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Fleeces from 2000 mixed age Merino ewes in each of 6 years were classed traditionally (i.e. by subjective assessment of fineness into 2 or 3 lines) or objectively (i.e. fleeces put into one line). Off-type fleeces (about 10\%) which differed markedly from the bulk of the clip were excluded from all the lines. The fleeces from 800 to 1000 Merino hoggets in each of 6 years were also used in comparisons of traditional and objective classing. The fibre diameter of each objective (OCP) line was very similar to the weighted mean of the corresponding traditional (TP) lines. Clean auction prices for the OCP lines were 0.8\% and 1.0\% lower than the weighted means of the TP lines for the ewes and hoggets, respectively. Research in Australia has shown that there is no difference in the processing performance of traditionally or objectively classed lines of fleece wool. The optimum classing method is therefore determined solely by the relationship between price and diameter. Wools 21 }, issn = {1176-5283}, author = {Sumner RMW and Hawker H} } @conference {39981, title = {Effect of post-weaning and post-mating/post-weaning shearing on ewe performance}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {45}, year = {1985}, month = {Jan}, pages = {221-224}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {No abstract supplied}, issn = {1176-5283}, author = {Sumner RMW and Willoughby LD} } @conference {39971, title = {Effect of steroid immunisation in the performance of 3 breeds of sheep under hill country conditions}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {45}, year = {1985}, month = {Jan}, pages = {181-183}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Forty Romney hoggets were immunised against oestrone during March. A similar number served as untreated controls. Half of each group was treated with progestagen sponges to induce oestrus. Their ovulation rates were determined 7 day after sponge withdrawal and in mated hoggets within 14 days of first oestrus. Half of the immunised ewes were boosted as 2- and 4-tooths, the balance receiving only a 4-tooth booster. Half of the untreated controls were first immunised as 4-tooths. Ovulation and lambing rates were recorded. Immunisation increased hogget multiple ovulation rates by 50\%. Unboosted 2-tooth ewes had multiple birth rates and numbers of lambs born similar to untreated controls. Boosted 2-tooths had more multiple ovulations (37\%), ewes lambing multiples (28\%) and lambs born (28\%) than control ewes. The ovulation rate of 4-tooth ewes was 2.24. Untreated control ewes had the lowest proportion of triple ovulating ewes (11\%), with first treated 4-tooths and 4-tooths missing their 2-tooth booster intermediate (22\%) and annually boosted 4-tooths highest (38\%). Control 4-tooths lambed fewest multiples (53\%), first treated 4-tooths were intermediate (63\%) and 4-tooths missing their 2-tooth booster and annually boosted 4-tooths highest (75\%). However, differences in 4- tooth ovulation and lambing responses were not significant. The limited data demonstrate that annual immunisation against oestrone can increase ovulation and lambing rates. Ewes missing an annual booster perform at levels similar to untreated control. Furthermore, the immunomemory system for oestrone appears to last for at least 24 months since the ewes gave birth to 189\% of lambs compared to 194\% in annually boosted ewes and 159\% in untreated controls.}, issn = {1176-5283}, author = {Knight TW and Smith JF and Sumner RMW} } @conference {39979, title = {Inheritance of loose wool bulk in Romney and Perendale sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {45}, year = {1985}, month = {Jan}, pages = {213-216}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Lifetime performance data were collected from flocks of 200 mixed-age Romney, Coopworth and Perendale ewes at Whatawhata Hill Country Research Station which were shorn either once yearly in November or twice yearly in May and November beginning in 1978, together with the lifetime performance data of 2-year-old replacement ewes entering these flocks in 1979 and 1980. Twice-shorn ewes were consistently heavier after shearing in November with an apparent carryover effect the following May. More of the twice- shorn ewes required dagging before shearing in November. There was a significant frequency-of-shearing x breed interaction for both total greasy and total clean wool production. Twice-shorn Romney and Perendale ewes grew more wool than once-shorn ewes. Wool growth of the Romney was greater following shearing in May compared with the other 2 breeds. Frequency of shearing did not affect ewe survival, number of lambs born, lamb survival, or weight of lamb weaned per ewe. Incidence of casting was insignificant. Average net wool returns were greater for once-shorn ewes.}, issn = {1176-5283}, author = {Bigham ML and Sumner RMW and Clarke JN and Johnson DL} } @conference {39879, title = {Effect of shearing on meat and wool production from lambs reared on hill country}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {44}, year = {1984}, month = {Jan}, pages = {45-48}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The effect of winter and early spring feeding levels, lambing status and ewe age on staple strength, fibre diameter at the point of break, and position of staple break were measured in pregnant Romney and Coopworth mixed-age ewes at Whatawhata and Ruakura, respectively. Mid-pregnancy feeding levels produced significant differences in staple strength (37 v 20 newtons/kilotex in the Romney; and 52 v 45 N/ktex in the Coopworth) and diameter at the point of break (37 v 34 }, issn = {1176-5283}, author = {Sumner RMW} } @conference {39827, title = {Effect of feeding and season on fleece characteristics of Cheviot, Drysdale and Romney hogget wool}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {43}, year = {1983}, month = {Jan}, pages = {79-82}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {About 4000 ewes born over 3 years to single sire matings were repeatedly scored for incidence and severity of dags. Dag scores were analysed for evidence of genetic variation and relationship to structural and performance characteristics. Perendales were found to have lowest incidence of dags followed by Booroola x Perendales, Booroola x Romneys and then Romneys and Border Leicester x Romney ewes. There was no relationship between dag score and either wool or body weight characteristics, either within or between breeds. Among progeny of 6 Romney strain, daughters of Ruakura High Fertility rams had substantially lower incidence with little variation among the rest. It is suggested that long-term selection for fertility in this line has reduced incidence of dags through improved utilisation of forage, possibly as a result of resistance to internal parasites. The mean heritability of dag score was 0.31 with a range of 0.13 to 0.60, indicating that selection would be effective in reducing the incidence of dags and their associated costs to farmers.}, issn = {1176-5283}, author = {Sumner RMW} } @conference {39826, title = {Fleece tenderness - a review}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {43}, year = {1983}, month = {Jan}, pages = {73-78}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The heritability of loose wool bulk and yellowness (CIE Tristimulus value Y-Z) and the genetic and phenotypic correlation of these with other wool traits were determined from data obtained on ewe hoggets born in 1979 and 1980 in the strains trial at Rotomahana. Heritability estimates were 0.41 }, issn = {1176-5283}, author = {Bigham ML and Sumner RMW and Hawker H and Fitzgerald JM} } @conference {39812, title = {Hogget lambing and its effect on the subsequent two-tooth performance of three breeds}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {43}, year = {1983}, month = {Jan}, pages = {21-24}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Lamb survival and birth weight data from a Booroola x Romney flock and a Booroola x Merino flock were collected between 1975 and 1981. The mean litter sizes for these flocks were 1.96 and 1.76 respectively, with litter sizes ranging from 1 to 4 within each flock. Effects of year, ewe age, birth rank and birth weight on lamb survival were assessed by fitting a sequence of logit models to the data. Birth weight was identified as the key parameter, with year and birth rank effects being markedly reduced once the variability due to birth weight was accounted for. An apparent ewe age effect was completely explained in terms of lamb birth weight. At any given birth weight lambs born to large litters (>/-3) had a lower probability of survival than contemporary lambs born as singles or twins.}, issn = {1176-5283}, author = {Moore RW and Sumner RMW and Bass JJ and Hockey H-UP} } @conference {39792, title = {Effects of castrating and surgically dehorning male Drysdale and Tukidale lambs on the efficacy of mechanical head skinning}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {42}, year = {1982}, month = {Jan}, pages = {141-144}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {No abstract supplied}, issn = {1176-5283}, author = {Sumner RMW and Longdill GR} } @conference {39724, title = {Effect of grazing management on hogget fleece characteristics}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {41}, year = {1981}, month = {Jan}, pages = {128-132}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Sumner RMW and During C and Webby RW} } @conference {39749, title = {Wool growth of ewes during autumn on hill country}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {41}, year = {1981}, month = {Jan}, pages = {283-287}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Sumner RMW and Smeaton DC} } @conference {39686, title = {Effects of short-term differential feeding in the autumn on liveweight gains and wool growth of ewes}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {40}, year = {1980}, month = {Jan}, pages = {209-214}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Sumner RMW and Rattray PV} } @conference {39687, title = {A review of effects of shearing on sheep production}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {40}, year = {1980}, month = {Jan}, pages = {215-220}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Smith ME and Bigham ML and Knight TW and Sumner RMW} } @conference {39285, title = {Some effects of an increased stocking level on wool growth}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {29}, year = {1969}, month = {Jan}, pages = {208-217}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Sumner RMW and Wickham GA} }