-The objective of this study was to determine how concentrate supplementation during late third gestation and lactation affects ewe and offspring performance from birth to weaning. Thirty-six ewes and their offspring (n = 32) were used. Eighteen Morada Nova and 18 Santa Inês ewes were artificially inseminated with semen from Dorper ram and distributed in a completely randomized factorial arrangement (2 × 2) consisting of two supplementation levels (5 and 15 g kg -1 of BW) and two breeds (Morada Nova and Santa Inês) or two crosses (Dorper × Morada Nova and Dorper × Santa Inês). The ewes were weighed, their body condition was evaluated during pregnancy, and the weaning weight of the lambs at up to 70 days old was measured. There was no effect of breed or supplementation on the prolificacy or type of birth. The Santa Inês ewes had a faster rate of development, although the weight loss during lactation was lower in the Morada Nova ewes. The weight development of the Dorper × Santa Inês lambs during the maternal-dependent phase was 34 g/100 g higher than that of the other cross, with no difference in the maternal-independent phase. Dorper × Santa Inês lambs gain more weight during the 70 days of development. However, the Dorper × Morada Nova lambs show a better response in terms of production efficiency when comparing the weight of the lambs with the weight of the sheep.

-The objective of this study was to evaluate the performance, qualitative, morphometric and quantitative carcass traits of Santa Inês lambs of different frame sizes finished in a feedlot. Twenty 120-day-old intact lambs with a 25.0±3.1 kg average body weight at the beginning of the experiment were used. Lambs received a diet containing 17% crude protein and 2.70 Mcal/kg dry matter. Frame size influenced performance and tissue composition in the carcasses of the lambs. Lambs with large frame sizes showed better carcass conformation compared with those of medium-sized frames. Frame size was found to have a significant effect on rump perimeter. Large-framed lambs showed higher compactness on the carcass index and carcass dressing area compared with medium-framed lambs. The cuts of large-framed lambs weighed more than those of mediumframed lambs. However, no significant differences were found in dressing.