Early socialisation in group lactation system reduces post-weaning aggression in piglets

Background: Pre-weaning group housing for sows and their litters is expected to enhance animal welfare. However, knowledge of potential benefits of pre-weaning socialisation for piglets after weaning is still lacking.

Methods: Weaner pigs were mixed in groups of 10, using littermates (LM) from pre-weaning group housing (Gr) and from farrowing pens with crates (Co). Groups were formed as follows: Gr/Gr (5 LM from Gr + 5 LM from Gr), Gr/Co (5 LM from Gr + 5 LM from Co), Co/Co (5 LM from Co + 5 LM from Co).

Results: During 24 h after mixing, piglets in Co/Co fought more than in Gr/Co and Gr/Gr. Piglets in Co/Co had more unclear fighting results than in Gr/Co and Gr/Gr. Four days after mixing, piglets in Co/Co were more injured than in Gr/Co and Gr/Gr.

Conclusion: Early socialised piglets may have better social skills when meeting familiar and unfamiliar conspecifics after weaning.