Genetic association between sow longevity and social genetic effects on growth in pigs.

Objective: Sow longevity is important for efficient and profitable pig farming. Recently, there has been an increasing interest in social genetic effect (SGE) of pigs on stress-tolerance and behavior. The present study aimed to estimate genetic correlations among average daily gain (ADG), stayability (STAY), and number of piglets born alive at the first parity (NBA1) in Korean Yorkshire pigs, using the SGE model.

Methods: The phenotypic records of ADG and reproductive traits of 33,120 and 11,654 pigs, respectively, were evaluated. The variances and (co) variances of the studied traits were estimated by an animal multi-trait model applying the Bayesian with linear-threshold models using Gibbs sampling.

Results: The direct effect on ADG had a significantly negative genetic relationship with STAY, whereas the social effect on ADG had a neutral genetic relationship. In addition, the genetic correlation between the social effects on ADG and NBA1 tended to be positive, unlike the direct effects. The genetic correlation of the total effect on ADG with that of STAY was negative but non-significant, owing to the social effect.

Conclusion: These results suggested that total genetic effect on growth in the SGE model might reduce the negative effect on sow longevity owing to the growth potential of pigs. We recommend including social effects as selection criteria in breeding programs to obtain satisfactory genetic changes in both growth and longevity.