Climate change is intensifying heat stress across all livestock species, with projected temperature increases threatening welfare, productivity, and survival. Cattle experience heat stress above 25°C THI (temperature-humidity index), causing reduced feed intake, increased water consumption, respiratory panting, and reproductive failure. Dairy cows lose 10–30% milk production during heat stress periods. Pigs, unable to sweat, are highly vulnerable; optimal temperatures are 18–22°C. Poultry mortality during heatwaves can reach 10–20%. Welfare-positive interventions include shade provision, sprinkler and misting systems, increased ventilation, nocturnal feeding schedules, and genetic selection for heat-tolerant breeds. Economic analyses show that cooling investment generates positive returns through maintained production and reduced mortality. Climate adaptation planning is now integrated into welfare assessment frameworks.