Shorn and unshorn Awassi sheep I. Body temperature

Abstract

1. The rectal temperatures of shorn and unshorn Awassi sheep were measured at various hours of the day and during various seasons of the year in two different locations in Israel. 2. An increase in body temperature accompanied an increase in environmental temperature. A steeper temperature increase was noted in shorn sheep kept in the shade. When ambient temperatures were below 30° C. the body temperature of shorn sheep was lower than that of the unshorn sheep by an average of 0·16° C. 3. When ambient temperatures were above 30° C. the body temperature of shorn sheep was equal to or higher than that of unshorn ones. 4. Upon exposure to direct sunlight, the body temperature of shorn sheep exceeded that of unshorn animals. However, when the animals were transferred to the shade, or after sunset, the shorn sheep cooled at a faster rate. Their body temperature fell below that of the unshorn sheep during the cool hours of the day. 5. Wind velocity, both in the shade and in the sun, had a greater effect on shorn than on unshorn sheep. 6. A rise in the relative humidity of ambient temperatures above 25° C. caused body temperature to rise, particularly in unshorn animals. The body temperature of shorn sheep exceeded that of unshorn ones when the animals were maintained in a hot and dry environment. 7. While the body of the shorn sheep was entirely affected by the macroclimate, the unshorn sheep were greatly influenced by the microclimate existing in the fleece. Fleece temperatures always lagged behind and were rarely equal to environmental temperatures. Since it was postulated that heat tolerance of certain animals was related to their ability to exploit cool hours of the day, it is suggested that in certain ‘tolerance tests’ records should be taken not only during exposure to heat but also during cool hours of the day.