Heat stress in farmed animals is intensifying with climate change. Understanding its welfare impacts and effective mitigation strategies is essential for farm animal welfare in a warming world.
Heat stress causes significant animal suffering and is a growing welfare emergency as climate change intensifies. Physiologically, heat stress triggers panting, reduced feed intake, behavioral agitation, and in severe cases hyperthermia leading to death. Chronic heat stress suppresses immune function, reduces growth rates, and causes reproductive failure — all indicators of compromised welfare. Mitigation requires multiple complementary strategies: shade access (the single most cost-effective intervention), ventilation systems, cooling sprinklers, wallowing areas for pigs, and adjusted feeding schedules to cooler parts of the day. Housing design choices made now will determine heat stress exposure for decades — white roofs, natural ventilation, and orientation relative to prevailing winds can dramatically reduce thermal load. Genetic selection for heat tolerance, particularly in dairy cattle, is a longer-term adaptation strategy. Regulatory requirements for shade and cooling infrastructure are emerging but enforcement is inconsistent.