Ratwan Poonam, Kumar Manoj, Mandal Ajoy
Department of Animal Genetics and Breeding, LUVAS, Hisar-125004, (Haryana), India.
Animal Breeding Section, Eastern Regional Station, ICAR-National Dairy Research Institute, Kalyani, Nadia-741235, (West Bengal), India.
Zygote. 2022 Oct;30(5):656-663. doi: 10.1017/S0967199422000120. Epub 2022 Jul 8.
The knowledge of genetic parameters of performance traits is crucial for any breeding programme in dairy animals. The present study was conducted to use a Bayesian approach for estimation of genetic parameters of production and reproduction traits in Jersey crossbred cattle. Data of Jersey crossbred cattle maintained at Eastern Regional Station, National Dairy Research Institute, West Bengal spread over a span of 41 years were utilized. The marginal posterior medians of heritability for 305-day milk yield (305MY), total milk yield (TMY), peak yield (PY), lactation length (LL), calving interval (CI), total milk yield per day of lactation length (TMY/LL) and total milk yield per day of calving interval (TMY/CI) were 0.31 ± 0.07, 0.29 ± 0.07, 0.27 ± 0.06, 0.16 ± 0.05, 0.15 ± 0.05, 0.29 ± 0.06, 0.27 ± 0.06, respectively. Moderate heritability estimates for 305MY, TMY, PY and production efficiency traits indicate the presence of adequate additive genetic variance in these traits to respond to selection combined with better herd management. Repeatability estimates for 305MY, TMY, PY, LL, CI, TMY/LL and TMY/CI were 0.57 ± 0.08, 0.58 ± 0.08, 0.51 ± 0.07, 0.34 ± 0.06, 0.31 ± 0.06, 0.54 ± 0.07 and 0.49 ± 0.07, respectively. Repeatability estimates for 305MY, TMY and PY were high in the current study, suggesting the use of first lactation records for early evaluation of Jersey crossbred cattle for future selection. Genetic correlations varied from 0.21 to 0.97 and maximum genetic correlation was observed between 305MY and TMY indicating that consideration of 305MY instead of TMY in breeding programmes would suffice. Positive genetic correlations of CI with 305MY and TMY indicated the antagonistic association between production and reproduction traits.
了解生产性状的遗传参数对任何奶牛育种计划都至关重要。本研究采用贝叶斯方法估计泽西杂交牛生产和繁殖性状的遗传参数。利用了位于西孟加拉邦的国家奶牛研究所东部区域站在41年期间饲养的泽西杂交牛的数据。305天产奶量（305MY）、总产奶量（TMY）、产奶高峰（PY）、泌乳期长度（LL）、产犊间隔（CI）、每泌乳期长度日产奶量（TMY/LL）和每产犊间隔日产奶量（TMY/CI）的遗传力边际后验中位数分别为0.31±0.07、0.29±0.07、0.27±0.06、0.16±0.05、0.15±0.05、0.29±0.06、0.27±0.06。305MY、TMY、PY和生产效率性状的中等遗传力估计值表明，这些性状存在足够的加性遗传方差，可通过更好的畜群管理来响应选择。305MY、TMY、PY、LL、CI、TMY/LL和TMY/CI的重复性估计值分别为0.57±0.08、0.58±0.08、0.51±0.07、0.34±0.06、0.31±0.06、0.54±0.07和0.49±0.07。本研究中305MY、TMY和PY的重复性估计值较高，表明可利用首次泌乳记录对泽西杂交牛进行早期评估，以供未来选择。遗传相关性在0.21至0.97之间变化，305MY和TMY之间观察到最大遗传相关性，这表明在育种计划中考虑305MY而非TMY就足够了。CI与305MY和TMY的正遗传相关性表明生产性状和繁殖性状之间存在拮抗关联。
