Effect of sire breed on carcass traits of meat lambs in Hidalgo, Mexico

The objective of the study was to evaluate the effects of sire breed (Charollais, Dorset and Texel), utilizing Hampshire ewes, lamb sex and birth type, on carcass traits of the lambs. After weaning (74+/-8 d), 45 lambs from these crosses were fattened during 63 d, consuming a balanced diet with 14% CP and 2.82 Mcal of ME/kg of DM. Lambs were weighed and slaughtered at 137 d of age; later, measures on slaughter weight and yield of hot and cold carcass, rib eye area, subcutaneous fat, carcass length, leg length, and rump perimeter were taken and the carcass compactness index was calculated. In addition, the carcass regional composition (shoulder, chest-belly, anterior-loin, leg, neck, and rear-loin) was determined. Data were analyzed utilizing a mixed model. Charollais-sired lambs had the highest (P<0.05) rib eye area (20.1+/-0.5 cm(2)), while Dorset-sired lambs were superior (P<0.05) in carcass length (66.3+/-0.9 cm) and leg length (34.8+/-0.3 cm). Ram lambs surpassed ewe lambs (P<0.05) in most traits analyzed. Lambs born as singles had higher means than twin lambs (P<0.05) in subcutaneous fat and leg length. In general, crosses with Charollais and Dorset showed superiority in carcass traits.