Effects of genotype and nutrition on sheep carcass fat and eye muscle development between weaning and 14 months of age

D.B. Binnie, J.N. Clarke, J.B. Clayton, C.M. Mowat, R.W. Purchas

Genetics Section, AgResearch, Ruakura Agricultural Research Centre, PB 3123, Hamilton, New Zealand

Proceedings of the New Zealand Society of Animal Production. 1995, 55: 104-107

Romney crossbred lambs (n=711) sired by selected Southdown high fat (SD+), low fat (SD-) and Texel rams were grown from weaning to 14 months of age under high(H), medium (M) or low (L) nutrition. A random half of H and L groups were run with the L and H groups respectively from 8 months onwards. Samples of lambs were slaughtered at 3, 5, 8, 11 and 14 months of age. Whereas there were significant carcass weight differences between nutrition and were almost always fatter than the SD- and Texel lambs. All genotypes showed markedly reduced levels of fat development during the post-weaning and winter periods, with highest levels in spring. Eye muscle width was more nutritionally responsive than eye muscle depth and, in relation to carcass weight changes, was greatest in winter.

Keywords: NZSAPAB; nutrition, genotypes; fat; eye muscle development

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Last Updated 25-01-1997