Consequences of Selection for Indirect Genetic Effect for Growth in Pigs on Behavior and Production

Abstract Text: Selection on indirect genetic effects for production traits may contribute to selection response, but validation through selection experiments is required. Our objective was to determine the consequences of selection for ‘IGE on growth rate’ (IGEg) on production traits and behavior of pigs. Sires (n=24) and dams (n=64) were selected to create a high vs. low contrast for IGEg in the offspring (n=480). The contrast was 2.8 g average daily gain (ADG) per group mate. Offspring were studied in a 2×2 arrangement with IGEg (high/low) and housing conditions (conventional/enriched) to examine genotype-by-environment interactions. Selection did not alter production traits, including ADG. Behavior showed consistent changes, whereby high IGEg pigs showed less biting behavior towards group mates and objects. There were no G×E interactions, but enrichment had a positive additive effect to selection. Despite the lack of response in ADG, behavior improved.

Keywords: indirect genetic effect; behaviour; pigs