The age at which piglets are weaned from their mothers has significant welfare implications for both sow and piglets, with evidence that very early weaning causes lasting behavioural and physiological harm.
Weaning age in pigs represents a genuine conflict between commercial incentives — earlier weaning returns sows to productivity faster — and piglet welfare. The evidence that very early weaning at or before 21 days causes lasting behavioural harm through disruption of normal suckling, social learning, and gut development is substantial. Post-weaning belly-nosing, where weaned piglets root against each other's bellies seeking the suckling contact they have lost, is a widely recognised indicator of welfare compromise from premature weaning. Gut health effects are also significant — the immature gut of early-weaned piglets is more susceptible to pathogenic colonisation, leading to post-weaning diarrhoea that affects welfare and requires antibiotic treatment in many systems. Later weaning at 28 days or beyond reduces these harms and is associated with reduced antibiotic use — an important co-benefit given antimicrobial resistance concerns. Consumer and legislative pressure for later weaning ages represents a welfare improvement that also addresses antibiotic use, making it an area where welfare and public health interests align.