Thermoregulation

It is the control or regulation of the body temperature that the animal carries out by means of different mechanisms and behaviours. The homeothermic organisms keep their body temperature more or less constant under a wide range of environmental conditions. Pigs, as humans, are homeothermic organisms (this is, their own heat roduction compensates for the losses). The normal rectal temperature of a pig is 38.7–39.8ºC, but it depends on the life stage  of the animal:

M Straw. Diseases of Swine. 7th edition