Effect of the Dorper breed on the performance, carcass and meat traits of lambs bred from Santa Inês sheep

•The use of increasing levels of the Dorper genotype on Santa Inês ewes was evaluated.•The Dorper breed shorten the productive cycle of the lamb significantly.•The Dorper crossbreed lambs produced heavier commercial cuts with higher muscle tissue.

The objective of this study was to evaluate the effect of the Dorper breed on the growth performance, feed efficiency, carcass and meat traits when crossbred with Santa Inês sheep raised under an intensive production system in the northeastern region of Brazil. Twenty-four lambs were used in this trial under a fully randomized design. The lambs were housed and creep fed until weaning at 62 days of age. After weaning, they were sent to a feedlot for finishing with a high-energy diet until slaughter, which occurred when the lambs attained a 3 mm thickness of subcutaneous fat. The Dorper crossbred lambs exhibited a higher daily gain (223.8 g/day) than the Santa Inês pure lambs (168.1 g/day) and attained the slaughter fat thickness (132 days) more quickly. Significant differences were observed between the crosses and the Santa Inês lambs in terms of the carcass weight, rib eye area, carcass and leg compactness indexes, weight and dressing of commercial cuts and the muscle:bone ratio. According to the results obtained under the described experimental conditions, at the same maturity level, the growth performance, the age at slaughter and the main carcass characteristics were conclusively improved by crossbreeding of the Santa Inês ewes with the Dorper rams, making the use of local sheep breeds possible, to efficiently meet the needs of the domestic market.