Effect of Dietary Protein, Slaughter Weight and Sex on Carcass Composition, Organoleptic Properties and Cooking Losses of Lamb

Abstract

Sixty crossbred lambs in each of 2 years were grown alike to weaning (18 kg), then fed in drylot on rations containing 10 or 16% protein the first year and 13 or 16% protein the second year. Lambs were fed in groups of five to predetermined slaughter weights of 36, 45 or 54 kg, at which time they were slaughtered. Carcasses were graded and cut. One-half of each was ground and analyzed for protein, fat, water and ash. A rib roast from each was cooked, evaluated organoleptically and for shear tenderness. Ewe carcasses were generally fatter and had less moisture than wether carcasses. As carcasses became heavier, they contained more ether extract and less moisture and protein in both sex groups. Ration protein level had very little effect on carcass fat measurements or yield of wholesale cuts. Carcasses from the 16% protein group, however, contained more moisture and less ether extract in 1971 when compared to 1972. Drip losses were higher (P<.01) for heavier carcasses, which were fatter, than for lighter carcasses and higher (P<.05) for the low-protein group in 1971 which also were fatter than the high-protein group. Total cooking losses increased as carcass weight increased with the difference being significant (P<.05) in 1971. Only minor differences in palatability traits were noted and all roasts were highly acceptable. Copyright © 1976. American Society of Animal Science. Copyright 1976 by American Society of Animal Science.