The age at which piglets are weaned directly affects their immune development, gut health, and welfare outcomes, with evidence strongly supporting later weaning as a welfare and health improvement.
Weaning age is a fundamental welfare determinant — earlier weaning imposes greater stress and immunological vulnerability at a critical developmental stage. The combination of social separation from the sow, dietary transition from milk to solid feed, and mixing with unfamiliar pigs creates a welfare crisis that is intensified in early-weaned piglets whose immune and digestive systems are less mature. The welfare evidence consistently supports later weaning: 28-day-weaned pigs show lower cortisol responses, lower diarrhoea rates, and better survival than 21-day-weaned cohorts. Extending weaning beyond 28 days in some production systems further improves outcomes. The welfare case for later weaning is also an economic case — healthier pigs require fewer antibiotics and have better growth rates.