Effect of microclimate on body temperature of black and white coloured breeds of goat

Abstract

The present experiment was carried out to compare the effect of microclimate on rectal temperature (RT)  and body surface temperature (BST) of black and white indigenous breeds of goat. Diurnal variation of  ambient temperature (AT) and relative humidity (RH) were recorded at hourly intervals inside goat pen  and temperature humidity index (THI) was calculated. The RT and BST (fore head, back, rump, flank, hind  cannon, udder and chest) were monitored twice a day (morning and afternoon) at fortnightly intervals in  twelve female goats (6 each of black and white body coat coloured breed). The mean AT, RH and THI of  pens were 24.86±0.98 ºC (ranged from 18.3 to 33.3 ºC), 51.06±2.51% (ranged from 30.4 to 70.9%) and  71.14±1.00 (ranged from 63.9 to 78.8), respectively. The RT and BST at fore head, back, rump, flank,  hind cannon and chest regions increased significantly from morning to afternoon (P<0.001). Coat colour  did not affect RT, but significantly affected BST at rump (P=0.048), hind cannon (P<0.001) and chest  (P=0.038). However, BST at fore head, back, flank and udder was not influenced by coat colour. There  was significant interaction effect of time of day and coat colour on BST at back region (P=0.039), where  BST increased markedly in white coloured goats than their black counterparts (11.24 vs. 8.19%). The  results indicated that the goats experienced mild to moderate heat stress. The coat colour influenced body  surface temperature of goats in certain body regions; however, heat tolerance ability of black and white  coloured goat breeds did not differ.