Sharma A K, Rodriguez L A, Wilcox C J, Collier R J, Bachman K C, Martin F G
Dairy Science Department, University of Florida, Gainesville 32611.
J Dairy Sci. 1988 Mar;71(3):819-25. doi: 10.3168/jds.S0022-0302(88)79622-8.
Objectives were to evaluate effects of interactions of maximum temperature, minimum relative humidity, and solar radiation on milk yield and constituent traits. Effects of climate variables and their interactions were significant but small in most cases. Second order regression models were developed for several variables. Six were examined in detail: Holstein and Jersey milk yields, Holstein fat and Feulgen-DNA reflectance percent, and Jersey protein percent and yield. Maximum temperature had greatest influence on each response, followed by minimum relative humidity and solar radiation. Optimum conditions for milk production were at maximum temperatures below 19.4 degrees C, increasing solar radiation, and minimum relative humidity between 33.4 and 78.2% (cool sunny days, moderate humidity). Maximum Holstein fat percent of 3.5% was predicted for maximum temperatures below 30.8 degrees C, minimum relative humidity below 89%, and solar radiation below 109 Langleys; actual mean Holstein fat percent was 3.35%. Optimum climatic conditions for Jersey protein percent were at maximum temperature of 10.6 degrees C with solar radiation at 300 Langleys and relative humidity at 16% (cool sunny days, low humidity). Because noteworthy interactions existed between climate effects, response surface methodology was suitable for determining optimum climatic conditions for milk production.
目标是评估最高温度、最低相对湿度和太阳辐射之间的相互作用对牛奶产量和成分特征的影响。气候变量及其相互作用的影响在大多数情况下是显著的，但影响较小。针对几个变量建立了二阶回归模型。详细研究了六个变量：荷斯坦牛和泽西牛的产奶量、荷斯坦牛的脂肪和福尔根 - DNA反射率百分比，以及泽西牛的蛋白质百分比和产量。最高温度对每个响应的影响最大，其次是最低相对湿度和太阳辐射。牛奶生产的最佳条件是最高温度低于19.4摄氏度、太阳辐射增加，以及最低相对湿度在33.4%至78.2%之间（凉爽的晴天，适度湿度）。预测最高温度低于30.8摄氏度、最低相对湿度低于89%且太阳辐射低于109兰利时，荷斯坦牛的最高脂肪百分比为3.5%；实际平均荷斯坦牛脂肪百分比为3.35%。泽西牛蛋白质百分比的最佳气候条件是最高温度为10.6摄氏度，太阳辐射为300兰利，相对湿度为16%（凉爽的晴天，低湿度）。由于气候效应之间存在显著的相互作用，响应面法适用于确定牛奶生产的最佳气候条件。
