Impact of Booroola Fecundity (FecB) Gene on Litter Size and Productivity of Nilagiri Synthetic Sheep

The study aimed to assess the impact of FecB gene on litter size and productivity in Nilagiri Synthetic sheep. A total of 179 ewes were screened for the FecB mutation between January 2015 and October 2016, and the reproductive performance of 158 non-carrier (++) and 21 heterozygous carriers (B+) was compared. Results indicated that ewes with one copy of FecB gene showed significantly (P<0.05) higher litter sizes at birth, weaning and in lifetime as compared to non-carrier ewes. The average litter size at birth was 1.09±0.10 for non-carriers and 1.60±0.10 for carriers, while the corresponding values at weaning were 1.09±0.11 and 1.56±0.12, respectively. Heterozygous carrier ewes (B+) weaned an additional 0.47 lambs per ewe compared to non-carriers. Further, in a lifetime, heterozygous carriers produced 3.13 more lambs at birth and 3.04 at weaning compared to non-carriers. These findings suggest that FecB gene contributes positively to prolificacy and overall reproductive performance in Nilagiri Synthetic sheep.