Welfare of Farmed Pigs During Extreme Heat Events

Pigs are among the most heat-sensitive farm animals because they lack functional sweat glands, making extreme heat events an acute welfare emergency in both indoor and outdoor production systems.

Key Facts

Pigs begin experiencing heat stress above 25 degrees Celsius and high humidity thresholds
Heat stress causes reduced feed intake, elevated respiratory rate, elevated cortisol, and reproductive failure in sows
Outdoor pigs in summer in temperate regions can experience severe heat without access to wallowing or shade
Evaporative cooling systems in indoor pig facilities reduce heat stress but require maintenance and electricity
The 2019 European heat wave caused significant but poorly documented pig mortality across France and Germany
Pig mortality from acute heat stress can reach significant proportions within hours in failed cooling systems

Welfare Considerations

Pigs have an exceptional vulnerability to heat that makes adequate cooling infrastructure a basic welfare requirement rather than a luxury. As climate change increases the frequency and intensity of heat extremes, this vulnerability will cause increasing welfare harm without proactive adaptation. Minimum standards for shade, wallowing access for outdoor pigs, and mechanical cooling for indoor systems should be regulatory requirements enforced with monitoring. Emergency protocols for cooling system failures should be mandatory in all intensive pig facilities to prevent the rapid-onset mass suffering that ventilation failure can cause.

What You Can Do

Advocate for mandatory cooling and shade requirements for all pig farming systems
Support climate adaptation funding for pig farm heat management infrastructure
Choose pork from lower-stocking-density systems with documented cooling provisions
Raise awareness that climate change makes pig welfare challenges increasingly urgent
Support research into heat-tolerant pig breeds and alternative housing design