Thermal and nutritional status and the development of postnatal rise in minimum metabolic rate of the rabbit

(1) By 12–36 h of postnatal age, compared with 0–12 h, rabbits exhibited 27% rise in minimum metabolic rate (MMR); the high level was later maintained. (2) The early rise was similar in fed and unfed pups, but it was absent in animals unexposed to cold during this period. (3) Beyond the age of 36 h, the unfed pups could not sustain the high MMR. (4) The low MMR of >36–72 h old unfed pups was normalized by the age of >72–120 h if they were successfully fed (their weight increased by 31%), although the consumed milk was not yet incorporated into metabolically active body mass.