Liveweight loss in adult ewes is affected by their sires breeding values for fat and muscle

Rosales Nieto, C.A., Thompson, A.N., Macleay, C.A., Briegel, J.R., Hedger, M.P., Ferguson, M.B. and Martin, G.B. (2013) Liveweight loss in adult ewes is affected by their sires breeding values for fat and muscle. Proceedings of the Association for the Advancement of Animal Breeding and Genetics, 20 . pp. 311-314.

Abstract

Ewes that lose more weight at times of nutritional pressure may decrease farm profitability through reduced production but also through reduced stocking rates, increased supplementary feeding costs and labour. Liveweight profiles were derived from the splined liveweight data of adult ewes from the Sheep CRC Information Nucleus Flock and liveweight loss was analysed. This paper reports on the response of liveweight loss to sire breeding values for fat and muscle in two contrasting environments. Overall liveweight loss was affected by significant differences between site, sire breed, ewe age, and previous and current reproductive performance. Sire breeding values for fat were significant, and interacted with site. There was a reduction in liveweight loss as sire breeding values for fat increased at Katanning in WA but an increase in liveweight loss at Kirby in NSW. Sire breeding values for muscle were also significant and different for each site, with the effects being opposite to fat at each site. These results suggest that selection against fat or selection for increased muscling may compromise the ability of ewes to maintain weight during summer and autumn in dry Mediterranean climates, however this may not be applicable for all environments.

Publication Type:	Journal Article
Murdoch Affiliation:	School of Veterinary and Life Sciences
URI:	http://researchrepository.murdoch.edu.au/id/eprint/24610

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