Nine cowsheds were used, the differences between each cowshed are orientation （east-west or north-south）, cooling （with or without）, and height （3 m, 5 m or 8 m height）. Dry-bulb temperature, relative humidity, ...Nine cowsheds were used, the differences between each cowshed are orientation （east-west or north-south）, cooling （with or without）, and height （3 m, 5 m or 8 m height）. Dry-bulb temperature, relative humidity, dew point, shaded area, air velocity, and maximum temperature were measured beneath each shed. The temperature-humidity index （THI） and the shading efficiency were calculated for each cowshed. The trials were conducted using 180 lactating Holstein Friesian cows; twenty cows housed beneath each shade structure. Measurements performed on cows were respiration rate, skin temperature, and rectal temperature; moreover, the milk produced by each cow was recorded, and the feed intake. High air velocities were recorded under high shade structures which enhance the aeration; consequently, maximum temperatures, and THI recorded beneath high sheds were less than those recorded beneath low sheds; also, skin temperatures, and respiration rates for cows housed under high sheds were less than those measured for animals housed under low sheds（differences were found to be significant）. Thereby, increasing shed height enhances dairy cows＇ microclimate under Egyptian conditions （hot climate）; consequently, the milk production increases. The best orientation is the east-west orientation, which is preferable for hot climates. The exploitation of cooling has significant effect on microclimate, cooling enhances the ambient environment and provides comfortable zone for dairy cows within which cows reach high production levels.展开更多
文摘Nine cowsheds were used, the differences between each cowshed are orientation （east-west or north-south）, cooling （with or without）, and height （3 m, 5 m or 8 m height）. Dry-bulb temperature, relative humidity, dew point, shaded area, air velocity, and maximum temperature were measured beneath each shed. The temperature-humidity index （THI） and the shading efficiency were calculated for each cowshed. The trials were conducted using 180 lactating Holstein Friesian cows; twenty cows housed beneath each shade structure. Measurements performed on cows were respiration rate, skin temperature, and rectal temperature; moreover, the milk produced by each cow was recorded, and the feed intake. High air velocities were recorded under high shade structures which enhance the aeration; consequently, maximum temperatures, and THI recorded beneath high sheds were less than those recorded beneath low sheds; also, skin temperatures, and respiration rates for cows housed under high sheds were less than those measured for animals housed under low sheds（differences were found to be significant）. Thereby, increasing shed height enhances dairy cows＇ microclimate under Egyptian conditions （hot climate）; consequently, the milk production increases. The best orientation is the east-west orientation, which is preferable for hot climates. The exploitation of cooling has significant effect on microclimate, cooling enhances the ambient environment and provides comfortable zone for dairy cows within which cows reach high production levels.
