Production performance of Barbados blackbelly sheep in Tobago, West Indies.

Data on 298 lambs from 161 ewes of the Barbados Blackbelly breed from 1982 to 1985 at the Blenheim Sheep Station in Tobago were studied to determine the influence of lambing season-year, sex and type of birth on body weights of lambs at birth, at 56 days (weaning) and 6 months of age, preweaning daily gain and mortality. The effect of the lambing season-year on litter size (total number of lambs born, born alive and weaned per ewe lambing) and total lamb weight at weaning were examined. The flock averages for body weights of lambs at birth, at 56 days and 6 months of age, preweaning daily gain and mortality were 2.75, 10.8, 19.2, 0.152kg, and 18.3%, respectively. Averages for total number of lambs born, born alive and weaned were 1.92, 1.88, 1.51, respectively, and total lamb weight at weaning was 16.7kg. The lambing season-year effect was apparent for all traits studied except for litter size and lamb mortality. Sex of lamb was not a significant source of variation. Type of birth had significant effect on lamb growth traits and total lamb weight at weaning. Single born lambs were heavier than those born as twins or more. Ewes with triplets or more weaned 21kg lamb weight compared to 18 and 12kg for twins and singles, respectively. Lamb mortality was 27.8% for those with below average birth weight and 8.8% for those with above average birth weight (P<0.05).