Climate change is increasing heat stress risk for farm animals. Heat stress causes significant welfare problems and is projected to worsen substantially over coming decades.
Heat stress causes a cascade of welfare problems. Animals reduce feed intake to reduce metabolic heat production, causing reduced growth and milk production. Panting requires energy and reduces productive efficiency. Physiological stress responses suppress immune function, increasing disease risk. Severe heat stress causes death from hyperthermia. Poultry in closed buildings with inadequate ventilation face the greatest acute risk. Climate-adapted housing design, shade provision for outdoor animals, and cooling systems are welfare interventions that also protect productivity.