Pigs are highly susceptible to heat stress and heat stroke because they cannot sweat effectively and rely on behavioral thermoregulation through wallowing, making access to cooling essential for welfare in warm climates.
Heat stress and heat stroke represent urgent welfare priorities in pig production because of the severity and rapidity of suffering they cause, combined with the fact that pigs are entirely dependent on human-provided cooling infrastructure when kept in confinement. Unlike cattle that can seek shade and utilize water sources, or species with functional sweat glands, pigs in indoor commercial systems without adequate cooling have no behavioral recourse when ambient temperatures rise above their thermal comfort zone. The physiological spiral from heat stress to heat stroke involves progressive hyperthermia, neurological compromise, cardiovascular failure, and death. Prevention requires proactive cooling system design including ventilation fans, evaporative cooling, water sprinklers, and access to wet wallow areas for outdoor pigs. Climate change makes heat stress management an increasingly critical component of farm animal welfare across wider geographic areas and longer seasonal windows.