title: Indirect genetic effects for growth rate in domestic pigs alter aggressive and manipulative biting behaviour.
abstract: Indirect genetic effects (IGEs) are heritable effects of an individual on phenotypic values of others, and may result from social interactions. We determined the behavioural consequences of selection for IGEs for growth (IGEg) in pigs in a G × E treatment design. Pigs (n = 480) were selected for high versus low IGEg with a contrast of 14 g average daily gain and were housed in either barren or straw-enriched pens (n = 80). High IGEg pigs showed from 8 to 23 weeks age 40% less aggressive biting (P = 0.006), 27% less ear biting (P = 0.03), and 40% less biting on enrichment material (P = 0.005). High IGEg pigs had a lower tail damage score (high 2.0; low 2.2; P = 0.004), and consumed 30 % less jute sacks (P = 0.002). Selection on high IGEg reduced biting behaviours additive to the, generally much larger, effects of straw-bedding (P < 0.01), with no G × E interactions. These results show opportunities to reduce harmful biting behaviours in pigs.
authors.affiliation: Department of Animal Sciences, Adaptation Physiology Group, Wageningen University, PO Box 338, 6700 AH, Wageningen, The Netherlands, irene.camerlink@sruc.ac.uk.
authors.forename: Irene
authors.initials: I
authors.lastname: Camerlink
authors.forename: Winanda W
authors.initials: WW
authors.lastname: Ursinus
authors.forename: Piter
authors.initials: P
authors.lastname: Bijma
authors.forename: Bas
authors.initials: B
authors.lastname: Kemp
authors.forename: J Elizabeth
authors.initials: JE
authors.lastname: Bolhuis
mesh_terms: D000374:Aggression; D000827:Animal Welfare; D000818:Animals; D001522:Behavior, Animal; D001733:Bites and Stings; D001835:Body Weight; D005247:Feeding Behavior; D005260:Female; D059647:Gene-Environment Interaction; D008297:Male; D010641:Phenotype; D034421:Sus scrofa; D013552:Swine