Pigs are highly susceptible to heat stress due to limited thermoregulation capacity, making warm weather a serious welfare challenge in intensive systems.
Heat stress in pigs causes acute suffering — affected animals are visibly distressed, panting, lethargic and reluctant to move. Chronic heat exposure reduces fertility, increases stillbirth rates, and suppresses immune function. In intensive indoor systems without adequate ventilation, temperatures can rapidly reach dangerous levels. Wetting systems, cooling pads and modified housing design can substantially improve welfare outcomes.