Effect of roof modification on micro-climate of animal shed

A study was conducted to compare the effect of roof modification with use of polycarbonate plastic sheet and its variable height on micro-climate of growing dairy heifers. The experiment was carried out on three sheds for three seasons, viz. hot-dry (summer) season, hot-humid (rainy) season and winter season. In control group (C), loose housing system was followed and corrugated cemented sheets were used as roofing material. In T1, polycarbonate sheets were used as roofing material with fixed height. In T2, polycarbonate sheets were used as roofing material with adjustable height. Daily ambient temperature (degrees C), dry and wet bulb temperature outside the shed (macro-climate) and inside the shed (micro-climate), Relative Humidity and Temperature Humidity Index were being recorded twice a day at 9.00 AM and 2: 30 PM for three continuous days at fortnightly interval. The average temperature of animal shed was significantly lower in T2 (27.30 +/- 0.10), followed by T1 (28.28 +/- 0.04) and C (29.46 +/- 0.16). In T2 lower temperature of shed than control was recorded during summer. Increasing the height of shed with ridge ventilation might have helped to dissipate heat easily in T2. The overall THI was significantly lower in T2 (76.50 +/- 0.16) followed by T1 (77.91 +/- 0.05) and higher in control (78.74 +/- 0.25), which might be due to less penetration of solar radiation via reflective polycarbonate sheet and higher height of roof in T2. The micro-environment was more conducive and comfortable in T2 than control. Polycarbonate roofing with adjusted higher height may be a desirable choice for animal housing to mitigate heat stress in summer.