Patterns of peripheral vasomotor function in near-natural conditions in the calf (Bos taurus)

Patterns of ear temperatures were examined in 2- to 45-day-old calves. At variable heat loads, peripheral temperature levels varied with the heat load with little fluctuations. When 2 to 3 days old, high ear temperatures were maintained for 10-14 hr/day at 10-15 degrees C ambient temperatures in 5 of 8 calves. In near-natural conditions, fluctuating ear temperatures were the rule in the vasodilated, intermediate and vasoconstricted states; fluctuations were symmetrical in the two ears in the vasodilated and intermediate states only. The possible occurrence of cold-induced vasodilation at 10-20 degrees C ambient temperature is discussed.