Pigs are highly susceptible to heat stress as they cannot sweat effectively. Climate change is making summer heat stress an increasingly serious welfare problem in pig production.
Heat stress causes significant welfare harm: panting and recumbency from discomfort, reduced feed intake leading to weight loss and reproductive problems, immune suppression increasing disease susceptibility, and in extreme cases hyperthermia and death. Pregnant and lactating sows are most vulnerable. High-welfare heat stress management includes adequate ventilation, cooling systems, reduced stocking density in summer, access to water for wallowing or wetting, and dietary adjustments to reduce metabolic heat load. As climate change intensifies summer heat events, welfare-protective cooling infrastructure becomes increasingly non-optional.