Performance of Zebu Heifers under Heat Mitigation Measures in a Humid-Tropical Environment

Productivity of bovine species is drastically reduced when the animals are subjected to heat stress as often occurs in tropical regions. Although zebu cattle are considered to be heat tolerant, their productivity could improve when cooling measures are applied to mitigate the effects of heat stress. In this study, twenty four Sokoto Gudali heifers under mean ambient temperature of 27.4 ­°C and temperature humidity index (THI) of 78 were subjected to four cooling treatments: no cooling (control), fan, shower and shower with fan. Rectal temperature of heifers reduced from 39.3 °C (in the afternoon) to 39.2, 38.5, 38.5 and 38.0 °C for control, fan, shower and shower with fan, respectively, one hour after administration of treatments. Dry matter intake (DMI) and growth rate of heifers increased significantly (P < 0.05) when cooling measures were applied. DMI of heifers varied from 2.08 to 3.78% of body weight (BW) while average daily gain (ADG) varied from 0.38 to 0.86 kg/d with cooled animals having the higher values. Application of cooling measures significantly improved the performance of zebu heifers raised in a hot and humid environment.