The present investigation was conducted to study the effect of heat ameliorating measures on micro-climatic variables in the loose houses during hot-humid season. In the study different heat ameliorative measures viz. control (T0), cooling jacket (T1), cooling jacket + forced ventilation (T2) and sprinkler + forced ventilation (T3)

were utilized to ameliorate the thermal stress in Murrah buffalo heifers (n = 24). Daily maximum and minimum temperatures relative humidity (RH) and temperature humidity index (THI) of both micro and macro climate were measured at 10.00 am and 2.00 pm of Indian Standard Time (IST) by using maximum and minimum and

dry and wet bulb thermometer. Significantly (P<0.05) lower maximum temperature was observed in T3, T2 and T1 groups (29.93 ± 0.19, 30.43 ± 0.18 and 31.27 ± 0.19oC, respectively) as compared to T0 group (32.25 ± 0.19oC). However, significantly (P<0.05) lowest minimum temperature was found in T3, T2 and T1groups (25.28 ± 0.22, 25.81 ± 0.23 and 26.60 ± 0.23oC, respectively) and higher minimum temperature in T0 group (27.60 ± 0.22oC). We observed significantly (P<0.05) lower RH in T3 and T2 groups (69.84 ± 0.57 and 71.93 ± 0.51%, respectively) than those of T0 (77.18 ± 0.49) at 2.00 pm. During the peak hot period significantly (P<0.05) lower temperature humidity index (THI) was reported in T3, T2 and T1 groups (78.89 ± 0.24 and 79.43 ± 0.25 and 81.39 ± 0.23, respectively) as compare to T0 group (82.36 ± 0.20). Therefore, it can be concluded that forced ventilation with

sprinklers or cooling jacket is an important mean to protect animals from thermal stress under loose houses during hot-humid season.