Birth weight and stillbirth genetic parameter estimation in a river buffalo simulated population

Stillbirth (SB) is a threshold character that has been detected as the most important factor affecting the future reproductive life of an animal. In buffaloes, stillbirth accounts for approximately 42% of all reproductive disorders being considered as the main reproductive disorder in buffalo calves. The present study aimed to estimate the heritability values and to determine the genetic and phenotypic correlation between stillbirth rate and birth weight (BW) using a Bayesian approach via Gibbs sampling method in a river buffalo population. A stochastic simulation was used to create a population in which random mating was used for 15 discrete generations. A bivariate animal model including maternal effects was used. Maternal effects were significant (p < .05) for both BW and SB. The results showed that when the SB rate increased from 1% to 50%, the estimated direct heritability of SB increased. Yet, by increasing the SB rate from 50% to 99%, a decrease of the SB estimated direct heritability was observed. The genetic correlation between BW and SB was decreased by increasing the level of occurrence of SB in the population from 1% to 99%. The root mean square error (RMSE) of heritability was increased from 40% to 70% level of occurrence of SB. Based on findings, it can be concluded that to reduce stillbirth rate in the population, it is possible to use genetic improvement program and birth weight could be one of the main components of a selection goal.