Climate change is creating urgent need for livestock welfare adaptation, with heat stress projected to become one of the leading causes of reduced welfare in food animals globally.
Heat stress in livestock causes a constellation of welfare impacts: elevated cortisol, reduced feed intake, immune suppression, reproductive failure, and ultimately heat stroke and death. Dairy cows in heat stress produce significantly less milk and have reduced conception rates. Pigs and poultry in inadequately ventilated buildings die in large numbers during heat events. Adaptation strategies include genetic selection for heat-tolerant traits, provision of shade and wallowing for pigs and cattle, improved building ventilation and cooling, and altered feeding times to avoid peak heat. Access to shade reduces heat stress significantly in outdoor cattle. The welfare benefits of heat adaptation coincide with production benefits, creating economic incentives for implementation. However, some systems are structurally unable to adapt without major investment.