Fifty (ten per breed) Merino, Polwarth. Corriedale, Romney Marsh and Texel lambs were castradet at 30 days of age and raised up to weaning (ten weeks) on native pasture at the Centro de Pesquisa de Pecuária dos Campos Sulbrasileiros (EMBRAPA), Southern (Bagé, RS) region of Brazil. Following weaning, the animals were feedioted during one week and each lamb was daily fed with 200 grams of a diet containing 17% of crude protein and 75% of dry matter basin. The animals were then moved to pasture up to 225 days of age when they were slaughtered to quantify and compare in vivo and carcass tosses and morphology. Liveweight (with and without a fasting period) was influenced by genotype. However, Merino, Polwarth and Corriedale live weight were not different among themselves, but lower than Romney Marsh lambs, which by their turn, were lower than Texel animals live weight. Fasting losses was significantiy affected when compared in absolute numbers (kg), bui not percentually. Highest tosses were observed in Texel breed lambs followed by Romney Marsh, whereas Corriedale, Polwarth and Merino didnot differ among themselves. Live weight carcass yield were significantly influenced by genotype. Heavier lambs showed superior carcass yield. Texel animals showed superior in vivo and in the carcass morphology, along wilh better conformation, body condïtion and body and carcass capacity, as cpmpared to other breeds.
sheep; lamb; morphology
