Thermoregulation and energy metabolism in the neonatal pig.

The period of 2-3 days following birth represents a critical period in the life of a pig. A major factor adversely affecting survival is the difficulty of the piglet to maintain homeothermy. Its thermoregulatory mechanisms available at birth become active immediately, but the thermogenesis is limited by the paucity of body energy reserves mainly composed of glycogen. Ingestion of colostrum is associated with a considerable increase in the metabolic rate which contributes to maintenance of body temperature. Within the first day of life, it is established that both heat production and rectal temperature are closely related to the level of colostrum intake. Failure to provide an adequate thermal environment reduces colostrum intake in the neonatal pig with corresponding effects on the development of the immunological and thermoregulation system. Finally, the key role of cold stress on neonatal mortality is discussed.