Commercial early weaning is one of the most significant welfare challenges for piglets. Understanding the impacts informs advocacy for reform of weaning practices.
Commercial early weaning compresses multiple major stressors into a single event: piglets simultaneously lose their mother, lose access to milk, experience a complete diet change, enter an unfamiliar environment, and are mixed with strange conspecifics. Each of these stressors alone would cause significant welfare impact; their simultaneous occurrence during a vulnerable developmental period produces compounding welfare harm. The consequences include post-weaning diarrhea, fighting and injury from mixing, immune suppression, and developmental trajectory changes that may affect lifetime welfare. Later weaning, even by a few weeks, substantially reduces these welfare costs. Regulatory minimum weaning ages have helped in some jurisdictions, but commercial pressure maintains very early weaning in most intensive systems.