A COMPARATIVE STUDY OF EFFECT OF DOCKING FAT-TAILED SHEEP AND CROSSBREEDING FAT-TAILED AND THIN-TAILED SHEEP ON GROWTH AND CARCASS CHARACTERISTICS

The effects of docking fat-tailed Salt Range lambs and crossbreeding of fat-tailed Salt Range X thin-tailed Kajli rams on growth and carcass quality were studied. Each of the three groups of experimental animals consisted of 12 male and 12 female lambs. Taking into account both breed and sex, the crossbred lambs were found significantly heavier than the purebred docked and undocked lambs at birth and at slaughter (at 13 months). Among the purebreds, undocked lambs showed non-significantly heavier live weight at 120 days weaning age. The trend, however, reversed and docked lambs weighed more by 1.35 kg than the undocked lambs at slaughter. Male lambs in all groups evidently exhibited better weight gain than females. Dressed carcass weight, shoulder and leg weights of purebred docked lambs were significantly (p<0.05) higher than those of undocked ones. Dressed carcass weight, dressing percentage and weight of loin and flank and leg cuts of crossbred F-1 lambs were higher than those of purebreds. Compared with purebreds, the crossbreds had higher percentage of lean and bone in 9-10-11 rib cut. Among the purebreds, the docked lambs had higher percentage of lean. fat and hone, the difference being non-significant. The thickness of back fat layer in purebred docked lambs was comparatively more than those of undocked and crossbred lambs at all locations except at rear end of the rump, where subcutaneous fat layer was markedly thicker in undocked lambs. Intra-and inter group comparison showed that females had significantly (p<0.05) thicker fat layer than that of males. These results may further be substantiated by using larger number of animals in each group.