Coat characteristics of goats in relation to heat tolerance in the hot tropics

Abstract

Heat tolerance in relation to coat characteristics was studied by exposing Sirohi goats to the sun for more than 8 h each day continuously for 5 days during the hot summer. Morning rectal temperatures and pulse rates were not influenced by coat type but dermal temperatures and respiratory rates were lower in long haired goats. In the afternoon after exposure, the short haired goats had higher respiratory and pulse rates than long haired goats. The increase in afternoon rectal temperatures, respiration rates and pulse rates over those recorded in the morning was higher in black followed by dark brown, light brown and white goats, in descending order. Water consumption was higher and feed intake during the hotter part of the day was lower in coloured goats than in white goats; feed intake was lowest in black goats. It was concluded that long haired goats tolerate radiant heat better than short haired goats and that white or light brown goats do better than dark brown or black goats. Short haired black goats had lowest tolerance of radiant heat as seen from physiological responses related to heat tolerance, water and feed intakes. Thus, it will be important to select long haired white or light brown goats for breeding and rearing in the hot tropics for higher productivity during summer months.