Effects of Changing Ambient Temperature on the Oxygen Consumption and the Body Temperature of Adult Angora Goats (Capra Aegagrus)

Farmers of Angora goats in the Karoo in the Eastern Cape, South Africa, experience large stock losses during cold and wet conditions. Information on the thermoregulatory responses of the goats to cold and wet conditions is scarce. We recorded the oxygen consumption (VO2), body temperature (Tb), skin temperature (Ts) and activity of six adult Angora wethers from the Karoo, at varying conditions of ambient temperature (Ta), fleece length and state of wetness. The experiments were conducted in an environmentally controlled room at the experimental temperatures 8°C and 20°C. Wetness resulted in the elevation of VO2 at 8°C, indicating increased metabolic rate in unshorn goats. The rectal temperature of the goats was within the normal range (38.5 – 39.7°C) at 8°C and 20°C. Homeothermy was partly achieved by the reduction of Ts, which reduced the temperature gradient between the skin and the surrounding air. For shorn goats, the reduction of Ts was 3 – 6°C between 8°C and 20°C while rectal temperature was constant; therefore the goats had to raise their VO2 to maintain their normal Tb. However, the dry shorn goats at 8°C had lower VO2 than at 20°C. It appears as if the goats abandoned endothermy and became torpid. There was no significant difference in activity of goats at different ambient temperatures. Activity of individual goats varied. The skin temperatures of the unshorn goats at 8°C and 20°C were more or less the same as were rectal temperatures. This suggests that the unshorn goats only used increased VO2 to maintain their body temperature while the shorn goats used both VO2 and Ts. It can then be speculated that the shorn goats were more susceptible to cold conditions than the unshorn goats which had less insulation and therefore enhanced conductance.