Bayesian approach for genetic analysis of production and reproduction traits in Jersey crossbred cattle.

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.