Carcass composition in weight-selected and control bulls from a serial slaughter experiment [beef cattle]
1993
Morris, C.A. | Bass, J.J. | Jones, K.R. | Wilson, J.A. (Ruakura Agricultural Centre, Hamilton (New Zealand)) | Baker, R.L. (International Livestock Centre for Africa, Nairobi (Kenya))
Bull calves were sampled at random at weaning from the 17th calf crop of an Angus herd selected for yearling weight (AS1) and from its contemporary control herd (ACO). Thirty animals per herd were slaughtered in groups of 5 per herd at intervals, from 7 to 25 months of age. Live weights and hot carcass weights of AS1 animals were, on average, 16.8 and 17.6 percent greater respectively than those of ACO animals. Allometric comparisons of the carcass composition data (log-log regressions) showed no significant herd differences in the rate at which saleable meat, bone or trimmed fat weights increased with carcass weight. Adjusted weights of bone, however, were significantly greater in the AS1 than ACO herds. There were significant herd differences in the weights of kidney, liver and testes, in scrotal circumference and in the concentrations of IGF-1, but these disappeared after adjustment for live weight. On an adjusted basis, heart weight was 6.1 percent greater in the AS1 than the ACO herd.
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