Heat stress in cattle causes significant welfare impacts and production losses, and climate change is increasing the frequency and severity of heat events on farms worldwide.
Heat stress causes cattle to increase respiratory rate, reduce feed intake, seek shade, and reduce activity. Severe heat stress leads to hyperthermia, metabolic acidosis, respiratory alkalosis, and can be fatal. Dairy cattle in high-yield production are particularly vulnerable because metabolic heat generation from milk synthesis adds to the thermal load. Welfare-centered heat management includes providing adequate shade for all cattle, access to cool clean water, evaporative cooling systems in housed cattle, and avoidance of handling and transport during the hottest parts of the day. As climate change increases heat events, investment in heat mitigation infrastructure is becoming a welfare imperative.