Burlap and buddies: the effects of social enrichment (preweaning mixing) and object enrichment (burlap) on piglet behavior and welfare in the postweaning environment

Abstract

The process of weaning piglets in commercial swine operations subjects them to numerous abrupt and stressful changes often resulting in negative welfare consequences. The objective was to study the post-weaning effects of early-life (1-3 days of age) pre-weaning socialization in multi-litter groups as well as object enrichment (burlap sheet) in the pre- and post-weaning environment by comparing 6 treatments that combined mixing of 1 vs. 2 vs. 4 litters mixed pre-weaning with and without burlap provision. An ANOVA linear model was run on all normal data, expressed per experimental unit (and behavior data were averaged over time), while non-normal data were analyzed using the Kruskal-Wallis test. Non-enriched groups of piglets were observed manipulating pen objects more often than the enriched groups (P = 0.005). Biting behaviors, including the chewing of ears and tails of pen-mates but excluding fighting, were observed the least in groups of pigs of 4 litters mixed pre-weaning, while piglets that were not mixed pre-weaning were observed biting the most (P = 0.03). Piglets who were not mixed pre-weaning also manipulated the burlap more frequently than the piglets from groups of 4 litters mixed pre-weaning (P = 0.02). Biting (P < 0.001) and displacements (P = 0.03) and fighting (P = 0.002) throughout the pen were observed less in the enriched groups. There were fewer lesions per pig in the enriched groups vs. non-enriched groups initially (P = 0.07) and one week after weaning (P = 0.10). Furthermore, pigs mixed in groups of 4 litters pre-weaning also tended to have lower lesion scores (P = 0.07) 1-week post-weaning compared to the other treatments. However, there were no differences between treatments in the proportion of piglets resting, eating/drinking, being active, or using the burlap, or for the observed frequency of displacements at the feeder, social behaviors, or belly nosing (P > 0.10). Overall, social enrichment encourages socialization with unfamiliar conspecifics at a younger age while object enrichment allows pigs to redirect their attention toward objects such as burlap. Both may improve pig behavior and welfare after weaning.