Estimates of genetic trends in a closed flock of Bharat Merino sheep

Abstract

The genetic and phenotypic trends over 15 years (1982-96) of multiple trait selection in a closed flock of Bharat Merino sheep were estimated. The estimates of genetic trend in body weights at birth, 3, 6 and 12 months 0f age, pre- and post-weaning growth rates, first, second and adult six-monthly greasy fleece weights, staple length, fibre diameter and medullation percentage were -0.064±0.057, -0.327±0.264, -0.335±0.343, and -0.180±0.477 kg, -2.842±2.722, and 0.191±1.428 g, 0.059±0.021, 0.014±0.026 and 0.040±0.006 kg, -0.029±0.123 cm, -0.160±0.279 microns and 0.970±0.837, respectively. These estimates revealed significant genetic improvement only in the first and adult six-monthly greasy fleece weights but little or no improvement in rest of the traits. The phenotypic trends only in 6-mo body weight (0.603±0.183 kg) and fibre diameter (-0.3154±0.146 microns) were desirable and significant. There is, therefore, a need for reviewing the ongoing breeding plans for faster genetic improvement in this flock of Bharat Merino Sheep.