Pig Heat Stress: Welfare in a Warming Climate

Pigs are highly vulnerable to heat stress due to limited thermoregulatory capacity. As global temperatures rise, heat stress is becoming an increasingly serious welfare problem on farms across Europe and beyond.

Key Facts

Pigs lack functional sweat glands and rely on wallowing, shade, and evaporative cooling from wet skin to thermoregulate
Heat stress begins at temperatures above 25-27 degrees C for growing pigs and 22-24 degrees C for gestating sows
During heat stress, pigs reduce feed intake, show reduced activity, and experience significant physiological disturbance
Chronic heat stress causes reduced growth rates, impaired reproductive performance, compromised immune function, and increased mortality
Sows experiencing heat stress during gestation have smaller litters, weaker piglets, and reduced colostrum production
Sprinkler systems, mechanical ventilation, and insulated housing can significantly mitigate heat stress
Climate change projections indicate that heat stress conditions will occur for 50-100 additional days per year by 2050 in southern Europe
Outdoor pig systems offer wallowing opportunities but also remove the protection of insulated buildings during heat waves

Welfare Considerations

Heat stress causes acute suffering in pigs - panting, lethargy, refusal to eat, and collapse in severe cases. Chronic exposure to sub-critical heat stress causes prolonged physiological discomfort and production losses. Current housing systems in many European countries are designed for cooler historical climate conditions and are increasingly inadequate as temperatures rise. The welfare impacts fall hardest on sows in gestation crates who cannot move to cooler areas, and on pigs in poorly ventilated buildings where heat accumulates. Adapting farm infrastructure for a warming climate is an urgent welfare and economic priority that requires investment and planning now.

What You Can Do

Advocate for mandatory heat stress management plans as part of farm welfare licensing requirements
Support producer associations and farm advisory services in developing heat stress protocols and infrastructure guidance
Choose pork from producers with verified heat stress management systems as part of welfare standards
Engage with retailers to require heat stress management in their pig welfare sourcing standards
Support climate adaptation research in livestock production systems
Advocate for rapid decarbonisation to limit the degree of climate warming that will require costly adaptation