Effects of Ambient Temperature on Calf Welfare Parameters During Long-Road Transportation

In the tested ambient temperature range (i.e., between −7 and 30°C), it was asserted that calves physical regulatory system of temperature homeostasis regularly works, particularly under ambient winter conditions. In summer, only ambient temperatures near 31°C could lead to reduced operation of the thermoregulatory center with the presence of clinical signs. This finding is strengthened by the correlation between ambient and rectal temperatures (R 2=0.57; P<0.001); rectal temperature appears to remain constant within an ambient temperature range between 8°C and 28°C. Furthermore, ambient temperatures lower than −7°C cause a slight reduction in body temperature, while values higher than 29°C result in a more than proportional physical temperature increase, which are better interpolated using a polynomial equation.