How intensive selection for large litter sizes in pigs has created welfare problems for piglets and sows, and what better breeding strategies look like.
The selection of pigs for extreme litter sizes represents a case where breeding for one production metric has created compounding welfare problems across multiple dimensions. Sows with very large litters produce insufficient colostrum per piglet, increasing disease susceptibility. Small, poorly nourished piglets compete intensely for teats, suffer from cold, and die at high rates. The sows themselves endure the physical burden of large pregnancies and extended nursing. This is not a situation where better management alone can fully compensate — the breeding decision itself has created a welfare problem that requires a breeding solution. Reconsidering litter size as the primary selection criterion is increasingly recognised as a welfare and sustainability imperative.