The effect of environmental temperature during pregnancy on thermoregulation in the newborn lamb

摘要: Twenty-four pregnant Scottish Blackface ewes were divided into three temperature-treatment groups 14 days before expected lambing: closely shorn and kept at 6°C (cold treatment, CD); in full fleece 26°C (warm WM); (controls, CL). Food allocation intakes similar for each group. Their lambs tested cold-induced summit metabolic rate capability (SMR) on the day of birth a mean age 12 h using water immersion to provide cooling. On following day, calorigenic response subcutaneous injections noradrenaline (NA) was measured assess non-shivering thermogenesis capability. The blood-sampled during pregnancy after SMR test.In ewes, blood glucose free fatty acid levels higher cold but not significantly so. Blood lower from CD (CD lambs) tests; other differences significant.During test, highest lambs, Rectal temperature declined least test (P < 0·05).The peak (PMR) NA injection about 1·5 times greater than CL WM 0·05). elevation PMR over thermoneutral respectively: 2·8, 1·8 1·7 CD, 0·05), this sustained longer 0·01). Thus, total markedly lambs.It concluded that exposure late favoured deposition (or checked normal decline in) foetal brown adipose tissue, so raising neonatal capacity thermogenesis.