Pig Wallowing and Thermoregulation Needs

Pigs cannot sweat and depend on wallowing in water or mud for thermoregulation, making the absence of wallowing opportunity a significant welfare deprivation in hot weather.

Key Facts

Pigs have very few functional sweat glands and rely primarily on respiratory cooling and wallowing
Heat stress begins in pigs at ambient temperatures above 25-27 degrees Celsius
Wallowing in mud or water provides cooling and also protection from sunburn in outdoor pigs
Outdoor pigs without wallowing opportunity suffer significant heat stress in summer
Misting systems and wallowing pools in outdoor systems significantly reduce heat stress
Wallowing behavior is highly motivated - pigs given access use it extensively in warm weather

Welfare Considerations

Pig thermoregulation welfare is a significant and seasonal issue for outdoor and semi-outdoor production systems. Unlike most mammals, pigs cannot effectively sweat, making them vulnerable to heat stress without wallowing opportunity. Access to water or mud for wallowing is a welfare necessity in warm weather, not a luxury. Outdoor pig systems without adequate wallowing provision subject animals to heat stress that causes reduced feed intake, reproductive failure, and physiological stress. Providing shade and wallowing areas in outdoor systems represents a basic welfare requirement during summer months.

What You Can Do

Choose outdoor pork from producers providing adequate shade and wallowing for their pigs
Support welfare standards requiring wallowing provision for outdoor pigs in warm climates
Donate to research on heat stress management and thermoregulation welfare in pig production
Advocate for mandatory wallowing provision requirements in outdoor pig farming regulations