Prediction and Evaluation of Urine and Urinary Nitrogen and Mineral Excretion from Dairy Cattle

Abstract

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.

Utilization of nitrogen in cows consuming wet distillers grains with solubles in alfalfa and corn silage-based dairy rations

“…In contrast to the reduced urinary N excretion for rations with WDGS, MUN concentration was not different among rations. Researchers have found a positive correlation between urinary N excretion and MUN (Kauffman and St-Pierre, 2001;Nennich et al, 2006). However, others have observed differences in urinary N excretion without a concurrent reflection in MUN (Ipharraguerre and Clark, 2005;Broderick et al, 2008).…”

Quantifying body water kinetics and fecal and urinary water output from lactating Holstein dairy cows

“…Therefore, accuracy of fecal and urinary water estimates considerably affects total fresh manure volume estimates. Several empirical models have been proposed to determine urinary (Holter and Urban, 1992;Bannink et al, 1999;Fox et al, 2004;Nennich et al, 2006;Khelil-Arfa et al, 2012) and fecal (Holter and Urban, 1992;Khelil-Arfa et al, 2012) water excretions from lactating dairy cows. The models of Holter and Urban (1992) and Khelil-Arfa et al (2012) were constructed using an integrated approach that connected water inputs and excretions.…”

Rapid assessment of feed and manure nutrient management on confinement dairy farms

“…Whereas much is known about biological relationships between what is fed to dairy cows, milk and manure production under experimental conditions (c.f., Broderick et al 2005;Wu et al 2000;Nennich et al 2005Nennich et al , 2006, relatively little information is available on feed and manure management under producer conditions. As the price of feed and fertilizers continue to increase dramatically, and livestock producers are increasingly held accountable for the overall environmental performance of their operations, new ways are required to track nutrient management in various components of farming systems.…”