SELECTION IN YANKASA SHEEP. 11. REALIZED RESPONSE IN BIRTH AND WEANING WEIGHTS

Abstract

The Yankasa sheep flock at the National Animal Production Research Institute, (NAPRI) Shika, and Zaria was studied to ascertain response realized in birth weight and weaning weight from selection for weaning weight. Also, paternal half sib analysis was used to obtain estimates of heritability and genetic correlation for the traits. Data on 597 birth and weaning weight records collected from 1984 to 1989 were analyses for selection response. For heritability estimates, 1,262 birth weight records and 699 weaning weight records were used. Results indicate genetic changes per year of 0.048 0.21 and 0.222 * 1.23 kg for birth weight and weaning weight, respectively. Genetic correlation between the two traits was 0.721 * 0.123. It was concluded that selection for weaning weight was fairly effective in improving both weaning weight and birth weight of lambs, due to the high heritability of the traits and the high genetic correlation between the two traits.