Effect of changes in scrotal temperature on food intake in pigs

1. Temperature of the scrotum or a similarly sized area of skin on the back of young pigs was changed by means of a thermal pad and food intake was measured. 2. Warming the scrotum to 42 degrees C significantly increased food intake in pigs reared and fed at 25 degrees C. 3. Cooling the scrotum to 20 degrees C, or changing the back skin temperature had no effect on food intake. 4. Acclimation to 10 degrees C, or exposure to 10 degrees C for 4 hr before a meal resulted in an increase in food intake. 5. Warming the scrotum did not affect this cold-induced increase in food intake. Warming the scrotum, but not the skin on the back, reversed the meal-induced increase in rectal temperature. 6. It is concluded that changes in food intake observed during warming the scrotum were not a direct result of the sensory information signalling increased skin temperature. 7. The likely mechanisms involved are the interactions of peripheral and deep body temperature, decreased deep body temperature and increased heat loss.