Growth performance, feed efficiency and carcass characteristics of lambs produced from Dorper sheep crossed with Santa Inês or Brazilian Somali sheep

The objective of this study was to evaluate the growth performance and carcass characteristics of crossbred lambs of Dorper sheep crossed with Santa Inês or Brazilian Somali sheep and raised under an intensive production system in the northeastern region of Brazil. A total of ten non-castrated male lambs of each genetic group were used in this trial under a fully randomized design. The lambs were housed and creep fed until weaning at 60 days of age. After weaning, they were sent to a feedlot for finishing with a high energetic diet until slaughter, which occurred when they reached 3 mm of subcutaneous fat thickness. The crossbred Santa Inês lambs exhibited a higher daily gain (0.3 kg/day) than the Brazilian Somali crossbred lambs, which were more precocious in reaching the slaughter fat thickness (118 days). Significant differences were observed between the genetic groups for the hot carcass weight, carcass shrink, and measurements of the rib eye area, the carcass and leg compactness indexes and the weight of the carcass joints. However, no significant differences were found for the amount of lean meat per cold carcass weight unity and the yield of retail cuts. The crossbred Brazilian Somali lambs presented a higher amount of fat per cold carcass weight unity (26 mm/100 kg) than the Santa Inês lambs. According to the results obtained and under the described experimental conditions, it may be concluded that at the same maturity level, the growth performance, the age at slaughter and the main carcass characteristics vary with the genetic group, making possible the use of local sheep breeds to meet efficiently the needs of different markets