The Metabolic Rates of Young Pigs Living at High Ambient Temperatures

Abstract

SUMMARY In 4 series of experiments pigs aged 12 days were weaned on to a pelleted diet and after 6 days were exposed in cages to ambient temperatures of 17, 25, 33 or 35°C. for a further period of 13–15 days. In each series litter-mates were divided between warmer and cooler environments. In 3 series of experiments the food intake of pigs of the cooler group was restricted to that taken voluntarily by pigs in the warmer group. Oxygen consumption rates and body temperatures measured over a range of ambient temperatures at the end of the period of exposure indicated some degree of adaptation to high ambient temperatures, in that sojourn at the higher temperature was associated with lower oxygen consumption rates. When the difference between exposure temperatures of the 2 groups in a series was small, control of food intake removed the difference between the cooler and warmer groups. When the temperature difference was larger, however, adaptation still occurred even when food intake was controlled. The restriction of food intakes in the cooler groups to those of the warmer groups tended to reduce or remove the differences in oxygen consumption rates between the 2 groups.