Pigs are highly susceptible to heat stress because they lack functional sweat glands, and rising global temperatures are increasing heat stress incidents in intensive pig production with serious welfare and productivity consequences.
Pigs in intensive systems face a structural vulnerability to heat stress because they cannot sweat effectively and have no access to mud wallowing. As climate change increases the frequency and severity of heat events, this vulnerability becomes an escalating welfare concern. During heat events, affected pigs experience physiological stress responses for extended periods. Pregnant sows are particularly vulnerable, and heat stress in gestation has documented effects on piglet health. Mitigation options exist — improved ventilation, evaporative cooling, building orientation, shade, and drip coolers — but capital cost presents barriers particularly for smaller producers. Welfare-focused regulations requiring cooling provisions in pig housing are needed to address this growing welfare risk.