Social genetics influence weaning performance in pigs

Indirect genetic effects (IGE), also called social genetic effects, are the genetic effects of an individual on a trait of another individual. This is increasingly studied in animal and plant breeding because IGE contribute to the accuracy of breeding estimates. Studies in livestock suggest that selection for IGE for growth (IGEg), meaning the genetic influence on the growth performance of group members, might increase animals’ capacity to tolerate stress. We assessed the effect of a stressful phase (weaning) on the behaviour and performance of 480 pigs selected for either high or low IGEg. High IGEg pigs were significantly slower to explore the feed and gained less weight than low IGEg pigs in the days after weaning. Although this is contrary to the initial hypothesis, it does suggest that high IGEg pigs may have prioritized the formation of social ranks over feeding.

Camerlink, I., Ursinus, W. W., Bartels, A. C., Bijma, P., & Bolhuis, J. E. (2018). Indirect Genetic Effects for Growth in Pigs Affect Behaviour and Weight Around Weaning. Behavior Genetics 48, 413-420.

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