Weaning is one of the most stressful transitions in pig production, causing diarrhoea, aggression, and growth depression that represent significant acute and chronic welfare problems.
Weaning induces multiple simultaneous welfare challenges: loss of the mother's social and nutritional support, introduction to unfamiliar piglets causing aggression, diet change causing gastrointestinal distress, and environmental change. The combination creates a welfare storm that often results in PWD, reduced feed intake, and impaired growth for 1-2 weeks post-weaning. Welfare improvements include: later weaning (28+ days rather than 21), providing transition feeds that mimic sow milk composition, ensuring adequate space to allow weaker piglets to escape aggression, maintaining stable social groups where possible, and hygiene protocols that reduce pathogen load. The zinc oxide ban has prompted development of probiotic and phage therapy alternatives, and welfare-centred weaning management protocols.