Nennich T D, Harrison J H, VanWieringen L M, St-Pierre N R, Kincaid R L, Wattiaux M A, Davidson D L, Block E
Puyallup Research and Extension Center, Washington State University, Puyallup, 98371, USA.
J Dairy Sci. 2006 Jan;89(1):353-64. doi: 10.3168/jds.S0022-0302(06)72101-4.
Urine excretion is a substantial factor in the amount of manure that needs to be managed, and urinary N can contribute to ammonia volatilization. Development and validation of prediction equations focusing on dietary factors to decrease urine and urinary nutrient excretion will provide information for managing urine and feces separately or for other future technologies. The objective of this study was to develop equations for prediction of urine excretion and excretion of urinary N, Na, and K and to evaluate both new and previously published prediction equations for estimation of urine and urinary nutrient excretion from lactating dairy cows. Data sets from metabolism studies conducted at Washington State University were compiled and evaluated for excretion of minerals. Urine excretion averaged 24.1 kg/d and urinary nitrogen excretion ranged from 63 to 499 g/d in the calibration data set. Regression equations were developed to predict urine excretion, urinary N excretion, and urinary Na and K excretion. Predictors used in the regression equations included milk yield, body weight, dietary crude protein percentage, milk urea nitrogen, and nutrient intakes. Previously published prediction equations were evaluated using data sets from Washington State University and the University of Wisconsin. Mean and linear biases were evaluated by determining the regression of residuals on predicted values. Evaluation and validation of prediction equations are important to develop equations that will more accurately estimate urine and urinary nitrogen excretion from lactating dairy cows.
尿液排泄是需要管理的粪便量的一个重要因素，尿氮会导致氨挥发。开发并验证侧重于饮食因素以减少尿液和尿中养分排泄的预测方程，将为分别管理尿液和粪便或其他未来技术提供信息。本研究的目的是开发预测尿液排泄以及尿氮、钠和钾排泄的方程，并评估新的和先前发表的用于估计泌乳奶牛尿液和尿中养分排泄的预测方程。对华盛顿州立大学进行的代谢研究数据集进行了汇编，并对矿物质排泄进行了评估。在校准数据集中，尿液排泄平均为24.1千克/天，尿氮排泄量在63至499克/天之间。开发了回归方程来预测尿液排泄、尿氮排泄以及尿钠和钾排泄。回归方程中使用的预测因子包括产奶量、体重、日粮粗蛋白百分比、乳尿素氮和养分摄入量。使用华盛顿州立大学和威斯康星大学的数据集对先前发表的预测方程进行了评估。通过确定残差对预测值的回归来评估均值和线性偏差。预测方程的评估和验证对于开发能够更准确估计泌乳奶牛尿液和尿氮排泄的方程很重要。
