James D. Kemp

Carcass and meat characteristics of crossbred lambs born to ewes of different genetic types and slaughtered at different weights

Physical, chemical and organoleptic properties of 113 carcasses from wether and ewe lambs of two genetic types — (SR) 12 Hampshire × 14 Suffolk + 14 Rambouillet and (FS)12 Hampshire × 14 Finnish Landrace + 14 Southdown — and slaughter weights of 32, 41 and 50 kg were compared. SR lambs at slaughter were younger, had heavier carcasses and lower dressing percentages. The carcasses had heavier legs, less fat, less kidney-pelvic fat and less breast and flank than FS carcasses. Rib roasts from FS lambs were more tender, juicy and flavourful than roasts from SR lambs although all were acceptable. Carcass fatness increased as weight increased. Carcass chemical composition was similar for the 41 kg FS lambs and the 50 kg SR lambs, indicating the maturity difference in the two genetic types. Ewe lambs were older at slaughter, had less carcass weight per day of age and were fatter than wether lambs. Feeding lambs to heavier weights was economically feasible for the SR type but FS lambs fed to 50 kg were often excessively fat.