ABSTRACT
Thermal Adaptation of the Neonate Neonates usually adjust to lower, more variable temperatures. The basal metabolic rate (BMR) after birth rises to a level about 3-times greater than the fetal rate (Part A). The body temperature (TB) may fall sharply following birth, but quickly recovers. The fall and recovery times vary with species, and environmental conditions. In foals and calves it is transient; in lambs recovery takes a few hours, but in pigs it may take a day. These animals are relatively mature at birth, as are primate and guinea pig infants. Newborn mice and rats are relatively immature, and it takes longer for their thermoregulatory mechanisms to develop. The kitten, puppy and rabbit are intermediate between these groups.
