Elliottdale and crossbred lambs: growth rate, wool production, fat depth, saleable meat yield, carcass composition and muscle content of selected cuts [sheep]
1992
Hopkins, D.L. | Gilbert, K.D. | Pirlot, K.L. | Roberts, A.H.K. (Tasmanian Dept. of Primary Industry, Kings Meadows (Australia))
Growth and carcass parameters were studied for 62 second-cross lambs (Poll Dorset rams over Border Leicester x Merino ewes) and 55 purebred Elliottdale lambs. Second cross lambs grew faster from weaning to the first slaughter time than Elliottdale lambs and consequently weighed more and had heavier carcasses. Elliottdale lambs produced significantly more wool between birth and weaning. The slope of the relationship between GR (tissue depths over the 12th rib 110 mm from the midline) and carcass weight was 1.24 mm per kg for second cross lambs and 0.82 mm per kg for Elliottdale lambs, indicating the latter lambs were leaner at heavier weights. Subjective assessment of fat distribution and carcass conformation by 2 assessors revealed a significant difference between breeds; second cross lambs having a better conformation. The legs of carcasses from crossbred lambs were shown to contain significantly more muscle than those of Elliottdales. Carcass weight explained some of the variation in weight of leg and forequarter muscle. This was improved by including an assessment for conformation from 1 assessor. Eye muscle area at the 12th rib did not add significantly to the prediction; it was not different between breeds, nor was its depth to width ratio different between breeds. The pH measurements of the M. longissimus thoracis et lumborum were similar between breeds.
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