Pigs are particularly susceptible to heat stress because they cannot sweat and rely on panting and wallowing for thermoregulation. Indoor pig production systems in temperate climates face increasing summer heat stress challenges as climate change raises ambient temperatures.
Pigs in heat stress show rapid breathing, open-mouth panting, reduced feed intake, and prostration. Core body temperature above 41°C is life-threatening. Sows in gestation units without cooling suffer reproductive failure silently — heat-induced embryo death reduces litter sizes without obvious clinical signs until birth. Boars experiencing heat stress show reduced sperm quality for 6-8 weeks after the heat event. Welfare interventions including misting systems, ventilation fans, cool floor pads, and adjusted feeding times to cooler periods of the day provide measurable benefits. Climate change projections indicate that heat stress welfare problems will intensify across all temperate pig production regions by 2030.