Positive emotions can reduce disease susceptibility during infectious challenges in humans, and emerging evidence suggests similar effects in farm animals. Because play behaviour may support a positive emotional state in pigs, this study investigated whether rearing pigs with regular intermittent play opportunities enhances disease resilience when challenged with porcine reproductive and respiratory syndrome virus (PRRSV). Litters were assigned to either play (PLY; n=5 litters) or control (CON; n=4 litters) treatments at birth. In PLY, play was promoted with extra space and enrichment items for three hours daily from five days of age (doa). At weaning (25±2 doa), 28 pigs (14/treatment) were selected for a disease challenge. The pigs were transported to a disease containment facility and at 43±2 doa (day 0 post-inoculation, DPI) inoculated with PRRSV. Play opportunities for PLY continued every other day until euthanasia of all pigs at 65±2 doa (22 DPI).
Results suggest that PLY pigs developed increased resilience to PRRSV compared to CON. Play pigs continued to play during infection, demonstrating less sickness behaviour and emphasizing the rewarding properties of play. This study demonstrates that rearing pigs in an environment supporting positive experiences through provision of play opportunities can enhance resilience against common modern production challenges, underscoring the value of positive welfare in intensive pig farming.
Rearing pigs with play opportunities: The effects on disease resilience in pigs experimentally inoculated with PRRSV (link to the full article)
