Early weaning in commercial pig production is one of the most welfare-significant events in piglet life, triggering a cluster of stressors that produce post-weaning diarrhea, growth checks, and immune vulnerability.
Weaning in commercial pig production is a welfare event that concentrates multiple acute stressors at a single developmental moment: separation from the sow and loss of milk nutrition, introduction to an entirely new social group requiring establishment of a new dominance hierarchy, transition to solid feed that the immature gut is not fully prepared for, and transport to a new physical environment. Each of these stressors alone would challenge a young piglet; combined, they create a welfare crisis that manifests as aggressive behavior, growth check, and post-weaning diarrhea affecting immune function and survival. Later weaning age — a single management change — simultaneously reduces the intensity of all these stressors by allowing greater gut maturity, social development, and behavioral competence before the weaning transition. The welfare case for later weaning is strong and supported by production evidence, but conflicts with economic incentives to maximize sow productivity through rapid return to estrus.