Livestock Heat Stress: Climate Change and Farm Animal Welfare

Rising global temperatures are increasing the frequency and severity of heat stress events in farm animals, with significant welfare implications for billions of cattle, pigs, and poultry.

Key Facts

Heat stress costs the US livestock industry an estimated $2.4 billion annually in reduced production and mortality.
Dairy cows experience heat stress at temperatures above 25 degrees Celsius combined with high humidity.
Broiler chickens are particularly vulnerable to heat: mortality during heat waves can reach 1-5% of a flock within hours.
Heat stress causes reduced feed intake, elevated respiratory rate, impaired immune function, and reproductive failure in livestock.
Shade provision, evaporative cooling, and ventilation significantly reduce heat stress in cattle and pigs.
Climate projections indicate increasing frequency and duration of heat events in most major livestock-producing regions.
Dark-colored or heavily feathered poultry breeds are more vulnerable to heat; breed selection can reduce heat stress risk.

Welfare Considerations

Heat stress in farm animals is a welfare emergency that is becoming more frequent as global temperatures rise. For broiler chickens in particular — which have been selectively bred for rapid growth that generates high metabolic heat — temperature spikes can cause mass mortality events within hours. Dairy cows under chronic heat stress experience suppressed immune function, elevated mastitis rates, and metabolic dysfunction in addition to the acute discomfort of thermoregulatory failure. Welfare-protective adaptations — shade, evaporative cooling, ventilation, access to cool water — are available and cost-effective but not universally provided. Climate change will increasingly make heat stress management a non-optional component of responsible livestock management. Building resilient production systems that can withstand increasing temperature extremes is both a welfare imperative and a commercial necessity.

What You Can Do

Support certification schemes that require shade, water, and cooling provisions for livestock during warm weather.
Advocate for livestock welfare standards to incorporate climate resilience requirements including heat stress management.
Support research into heat-tolerant livestock breeds and production adaptations for warming climates.
Engage with food companies on climate adaptation plans for their livestock supply chains.
Reduce livestock product consumption, particularly from species most vulnerable to heat stress in intensive systems.