Reducing aggressive behaviour in pigs
Number of skin lesions at the front of the body proves to be a good selection criterion to breed less aggressive pigs.
In indoor commercial farming systems, pigs are housed in inflexible group sizes under space-limited conditions. Pigs are often mixed with unfamiliar individuals throughout the production cycle and pigs fight to establish dominance when mixed into new social groups. This aggressive behaviour affects growth and is a welfare concern.
In collaboration with SRUC, researchers at The Roslin Institute examined the best trait to select upon in order to reduce pig aggressive behaviour. They used the number of skin lesions (scratches received) on different regions of the body to identify the least aggressive individuals to breed from.
Their results suggest that selection for reduced skin lesions at the front of the body at 24 h post-mixing results in the greatest reduction in aggressive behaviour and is therefore the best selection criterion of all analysed lesion traits to reduce aggressiveness at mixing.
In subsequent analyses, 16 locations in the genome (SNPs) were found to be associated with these skin lesions, whereby four of these were located within regions that have been associated with shortened life span and low stress resistance in model species. The team is currently exploring the social structure underlying high aggression at a pen and individual level, and the role of pig genetics on it.
Their findings have important implications for pig welfare and highlight the need for more multi-disciplinary research into the relationship between aggressive behaviour at mixing and aggression under stable social conditions.
Prediction of reduction in aggressive behaviour of growing pigs using skin lesion traits as selection criteria S Desire, S P Turner, R B D'Eath,A B Doeschl-Wilson, C R G Lewis, R Roehe (2016) Animal Vol: 10 Pages: 1243-1253, Genet Sel Evol. 48:11. http://dx.doi.org/10.1017/S1751731116000112