めん羊のノルアドレナリンおよびアドレナリンの尿中排泄におよぼす高温の影響〔英文〕

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Urinary excretion of noradrenaline and adrenaline, rectal temperature, heart rate, respiratory rate and urine volume were measured in three sheep (about 40kg of body weight) exposed to 20°C, 30°C and 35°C. The relative humidity employed was 70%. Mean urinary excretion of noradrenaline and adrenaline by the sheep at thermoneutral environment was 14.1 and 1.4bμg/24 hours, respectively, when rectal temperature, heart rate and respiratory rate were all within normal range. When the animals were exposed to 30°C, respiratory rate increased up to 100 breaths/min, but there were no significant changes in urinary excretion of noradrenaline and adrenaline, rectal temperature, heart rate and urine volume. When the environmental temperature became 35°C, respiratory rate increased to about 190 breaths/min, and rectal temperature increased by 1.3°C. Severe heat stress which was accompanied by hyperthermia, had no effects on the urinary excretion of noradrenaline and adrenaline as well as heart rate. It was concluded from the present and our previous results that the sympathicoadrenomedullary system of sheep was activated not by heat stimuli, but by cold stimuli.
社団法人日本畜産学会の論文