@conference {41620,
	title = {Protein fractionation prototype to extract minor proteins on-farm},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {88-92},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {The aim of this study was to investigate factors affecting, and estimate variance components of, stillbirth using data collected as part of Livestock Improvement{\textquoteright}s Sire Proving Scheme. Only calves that reached full-term of gestation were considered (i.e. abortions and inductions were excluded). After editing there were 773,904 records on calf-fatecollected from 1987 to 2004. The mean incidence of stillbirth was 7.2\%. The fixed effect model fitted tothe data included the effects of contemporary group, birth assistance code, the sex of the calf, the gestation length of the dam, whether the dam was primiparous or multiparous and mating type e.g. a Jersey cow mated to a Holstein-Friesian sire etc. Breed proportions of New Zealand (NZHF) and North American (OSHF) origin Holstein-Friesian and Jersey were also fitted in addition to the proportion of heterosis expected in the calf. Data wereanalysed by considering stillbirth as a binomial trait using the logit transformation in ASReml that included a sire-maternal-grandsire pedigree. The direct heritability of stillbirth was estimated to be 0.010 (s.e. 0.009). It was notpossible to estimate the maternal heritability using this dataset. Estimates of fixed effects were obtained from ASReml by analysing stillbirth as a continuous trait, as back-transformed fixed effect estimates obtained using a binomial model are unreliable when the incidence is small. The largest effect on the probability of stillbirth was calving difficulty. Compared to no assistance at calving, the two categories of greatest calving difficulty resulted in 22\% and 41\% mortality. The next largest effect on stillbirth was gestation length, with longer gestations being associated with more stillbirths. Males were 1\% more likely to be stillborn than females. OSHF were most likely to be stillborn, followed by Jerseys and then NZHF. Heterosis effects were significant and favourable, except between the two strains of Holstein-Friesians where there was no significant heterosis. The largest heterosis estimate was between NZHFand Jerseys. Unlike some overseas programmes, genetically selecting for reduced stillbirths would notbe effective in New Zealand, crossbreeding and devising strategies to manage calving assistance and gestation length appear to be more worthwhile.},
	issn = {1176-5283},
	author = {Chand A and Fee CJ}
}
@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 {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}
}
