Livestock Heat Stress: Welfare in a Warming Climate

Heat stress in livestock is an increasing welfare concern as global temperatures rise, causing reduced production, compromised immune function, and mortality in severe cases.

Key Facts

Dairy cows begin to experience heat stress at 21-24C depending on humidity, with serious health impacts above 30C
Heat stress reduces fertility, milk production, feed intake, and immune function in dairy cattle
Estimated global dairy production losses from heat stress exceed 1.7 billion dollars annually in the US alone
Broiler chickens and pigs have limited thermoregulatory capacity and are highly vulnerable to heat events
Shade, ventilation, water access, and evaporative cooling systems are the primary mitigation measures
Climate projections predict significant increases in heat stress days for livestock across Europe by 2050
Summer mortality events in poultry can kill tens of thousands of birds in a single ventilation failure incident

Welfare Considerations

Heat stress causes genuine animal suffering: panting, lethargy, reduced feed and water intake, and in extreme cases death. As climate change increases the frequency and severity of heat events, livestock welfare systems must adapt proactively. Ventilation system design, shade provision, and access to adequate cool water are minimum requirements during heat waves. The welfare and productivity losses from heat stress create economic alignment between welfare improvement and farm viability - a rare convergence that can drive adoption of better housing and management.

What You Can Do

Ensure livestock always have access to shade and fresh cool water during warm weather
Check ventilation systems before summer and ensure backup power for ventilation in poultry and pig housing
Monitor animal behaviour and production during heat events as early welfare indicators
Support research into heat-tolerant livestock breeds and cooling technology
Advocate for climate adaptation planning in agriculture to include livestock welfare considerations