@conference {41011,
	title = {Genetic parameters for liveweight and live animal ultra-sound fat and eye muscle dimension in a synthetic terminal sire breed},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {140-142},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {During 1993-97, approximately 7000 lambs were weighed at weaning (WW), re-weighted (LW) and ultrasonically scanned for subcutaneous fat depth (FD) and eye muscle dimensions (depth (MD) and width (MW)) at 6 months of age. Animals belonged to Landcorp{\textquoteleft}s {\textquoteleft}Lamb Supreme{\textquoteleft} terminal sire breeding programme, derived in 1989-91 from mainly Romney ewes mated to Romney, Wiltshire, Coopworth, Texel and Poll Dorset sires selected for fast growth and leanness. Records representing the selection criteria were analysed by univariate and multivariate animal-model REML methods able to take account of the effects of selection on variance components. Heritabilities were higher for LW (0.33 {\textpm} 0.03) than WW (0.28 {\textpm} 0.03) and litter contributions (as a proportion of phenotypic variance) lower (0.29 {\textpm} 0.02 and 0.44 {\textpm} 0.02, respectively). Heritability estimates for all traits were similar in both sexes except for MW, which was higher in females (0.34 {\textpm} 0.05) than males (0.23 {\textpm} 0.05). Averaged across sexes, estimates were: FD (0.30 {\textpm} 0.03), MW (0.29 {\textpm} 0.04) and MD (0.33 {\textpm} 0.03), litter contributions being lower for FD (0.13 {\textpm} 0.02) than MW (0.22 {\textpm} 0.01) or MD (0.19 {\textpm} 0.02). MD was closely related genetically with MW (0.97 {\textpm} 0.01), but less closely associated with LW (0.44 {\textpm} 0.06) than was MW (0.57 {\textpm} 0.05). Both muscle traits showed similar genetic correlations with FD (0.48 {\textpm} 0.07 for MW; 0.43 {\textpm} 0.07 for MD). Parameter estimates indicated positive genetic trends for LW (regression of estimated breeding values on year of birth) more than two-fold higher than those previously published, and with little concomitant increase in FD. },
	issn = {1176-5283},
	author = {Clarke JN and Nicoll GB and Mowat CM}
}
@conference {40809,
	title = {Repeatabilities of blood plasma metabolites and their associations with leanness in genotypes showing a wide divergence in carcass composition},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {180-183},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Strain differences in lean : fat partitioning were typified by a marked  contrast in a lean growth index giving equal but opposite emphasis to the  weights of protein and fat, in line with previous publications. Strains  showed characteristic differences in blood metabolites which did not  necessarily reflect genetic variations within a strain and correlated responses  to within-breed selection for changes in body composition. High repeatabilities of blood metabolites within a strain were found for  pasture-fed lambs aged between 5 and 14 months for samples collected on  the same day following overnight fasts of 20 vs 24 hours, but were lower for  samples taken from fasted animals at different ages. Between-age within- strain repeatabilities (averaged across two trials) were moderate for plasma  urea (0.24) creatinine (0.38) and non-esterified fatty acids (0.18), but low for  beta-hydroxybutyrate (0.09). Similar moderate heritability estimates were  found for urea and creatinine. Although standard errors were very high for  this small dataset based on only 12 sires, estimates for carcass composition  were in broad agreement with other more reliable published values. Also in  line with other results, sire-progeny variations in urea and beta- hydroxybutyrate were more positively related to carcass protein than carcass  fat, while the reverse was true for creatinine. Metabolically contrasting pairs  of metabolites showed potentially useful predictive associations with sire- progeny variations in protein:fat partitioning.},
	issn = {1176-5283},
	author = {Clarke JN and Binnie DB and Dobbie JL and Jones KR and Mowat CM and Purchas RW and Uljee AE}
}
@conference {40682,
	title = {Effects of genotype and nutrition on sheep carcass fat and eye muscle development between weaning and 14 months of age},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {104-107},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Although several studies have implicated cortisol in the control of  body composition in sheep, the precise mechanisms are unclear. Cortisol  basal concentration and response to an ACTH challenge was studied in  Coopworth wethers selected for (Fat) or against (Lean) fatness in both the  fed and 48 hour fasted states at two stages (15 and 33 weeks). The aim was  to investigate whether fasting, age or genotype would influence cortisol  secretory parameters.   Mean basal cortisol concentration was higher for fasted than fed lambs (13.6  versus 8.9 ng/ml, p<0.001), but did not differ significantly with genotype or  overall stage of development. Maximal cortisol response to ACTH was  greater for the fat than the lean genotype, at both 15 weeks (86.3 versus 65.3  ng/ml, p<0.01) and 33 weeks (108.2 versus 91.1 ng/ml, p<0.01) of age.   Maximal cortisol response was also significantly greater with fasting and  increasing age, but the effect of fasting on cortisol increase was greater at 15  than 33 weeks of age. Clearance of cortisol was significantly slower after  fasting, but unaffected (p>0.05) by genotype and development.   Basal cortisol concentrations was not associated with differences in body  composition between the fat and lean genotypes. However the larger  maximal response in the fat genotype may indicate that the adrenal gland  plays a role in determining body composition.  },
	issn = {1176-5283},
	author = {Binnie DB and Clarke JN and Clayton JB and Mowat CM and Purchas RW}
}
