TI 01. Sheep carcass characteristics of Ideal breed lambs and their crosses with Texel breed in two environmental conditions

A backcross program of the Ideal breed (I) to Texel (T) was carried out. Postweaning growth of lambs of both sexes of genotype T: (3/4T-1/4I) and I was evaluated during two months under two environmental conditions:TCO, feedlot experiment and TCA, range conditions. All lambs were weighed weekly. Those in feedlot were fed daily a ration of hay with commercial pellets. The relative ADG was evaluated as ADG/mean weight. Neither final weight nor growth rate gave significant differences between genotypes within the environment but differences were significant for each genotype throughout the two environmental conditions (P<.001). Male and female lambs of each treatment and genotype were taken for carcass assessment and twenty-seven measurements were made on each carcass. A principal component analysis was performed with these measurements, final weight and ADGr for the two treatments. 89 % of the total variance in the TCO was explained for the first two components. The higher values were for carcass weight, ADGr, proximal pelvic limb weight and the degree of fatness among others. A correlation coefficient of -0.62 was obtained between cold carcass weight and subcutaneous fat. Similar results were found for TCA. The first two principal components explained 87 % of the variance.