Draw of stress index of the summer hot environment by milk cattle with the global warming

点击翻译按钮获取中文摘要

In many milk cowshed at kyushu region, the dairy farming observed the reduction of production and quality in milk increasing the summer hot stress in summer season. The countermeasure of summer hot has generally spread to carry the ventilation fan and spray equipment. This research investigated about the temperature fall effect by the equipment of the venilation fan and spraying in milk cowshed, and analyzed by the effect making change of storage heat index in cattle body.The analysis method asked for each element about the heat balance formula of cattle body. The large difference of temperature could do the fall effect of the temperature descent with spray method.Morever, in the object cowshed, when 1g fog evaporated in 1m^3 it became clear that the temperature which is about 0.96℃ falls. If the change of heat balance factor are investigated in order to see the influence on cattle body by spraying, when spray is not being performed in daytime. The amount of storage heat by cattle body … More by spraying, when spray is not being performed in daytime. The amount of storage heat by cattle body increases gradually and exceeds 100W/m^2 around from 10:00 time. When spray was started, The temperature fell and sensible heat flux increased slightly. Since a cattle body surface side, got very wet latent heat flux increased greatly, and although the amount of storage heat fell till around 60W/m^2, it was still under summer hot environment. The simulation was carried out in order to investigate the conditions for leading the storage heat by spray method and the ventilation fan method of an object cowshed to the optimal environment used as 0W/m^2. By controlling the amount of evaporation and wind velocity 4m/s, the evironmental range which can be led to the optimal state is narrow, and cannot be led to the optimal state under summer hot environment. The strong wind which draws the optimal wind velocity controlling the temperature and relative humidity required in a place which are not spraying, and the influence of a strong wind becomes control feeding management with an problem. Then, it is found that change how to apply the wind to cattle body and how to scatter spray, and a wind hits three fourths of cattle body, carry out the case where it is made to get wet for fog further to assumption, and temperature corresponds to the optimal environment to 38℃ by the case of 60% of relative humidity and wind velocity 4m/s. Less