Genetic selection for increased litter size in pigs has created welfare challenges for both sows and piglets that require advanced neonatal management to address.
The welfare consequences of breeding for extreme litter size are distributed across both the sow and her piglets. Sows carrying and nursing very large litters experience significant metabolic demand and body condition loss during lactation. Piglets from large litters compete intensely for limited teat access, with smaller individuals at high risk of starvation during the critical colostrum period. The pre-weaning mortality that results from this system involves suffering from starvation and hypothermia for piglets that do not receive adequate nutrition. Welfare-focused pig breeding programs are beginning to incorporate total litter weight born alive and pre-weaning survival as balanced selection criteria alongside total born numbers.