Climate change is intensifying heat stress in farm animals globally, with welfare implications that require adaptation across species and production systems.
Heat stress in farm animals is a growing welfare crisis as climate change extends and intensifies periods of high temperature. Animals affected by heat stress experience physiological responses including increased respiration rates, reduced feed intake, impaired thermoregulation, and immune suppression - all of which compromise welfare and productivity simultaneously. Dairy cows begin showing welfare-relevant heat stress at temperatures above 25 degrees Celsius with high humidity - well within the range increasingly experienced in UK and European summers. Pigs lack sweat glands and rely almost entirely on panting and wallowing to cool themselves - in indoor housing without wallowing facilities and with inadequate ventilation, heat stress can cause deaths within hours. Poultry are similarly vulnerable. The welfare response required spans housing design (ventilation, shade, cooling systems), management (feed timing, stocking density reduction in summer), and genetic selection (heat-tolerant breeds). Higher-welfare systems that provide outdoor access may offer natural shade and cooling opportunities, but can expose animals to sun if shade provision is inadequate.