Diurnal and Dietary Impacts on Purine Derivative Excretion from Spot Samples of Urine

Authors

Grant I. Crawford, University of Nebraska-Lincoln
Kyle Vander Pol, University of Nebraska-Lincoln
James C. MacDonald, University of Nebraska-LincolnFollow
Galen E. Erickson, University of Nebraska-LincolnFollow
Terry J. Klopfenstein, University of Nebraska-LincolnFollow

Date of this Version

1-1-2007

Comments

Published in 2007 Nebraska Beef Cattle Report. Copyright © 2006 The Board of Regents of the University of Nebraska.

Abstract

An individual feeding experiment was conducted to estimate diurnal and dietary impacts on microbial CP (MCP) production estimated from urinary purine derivative (PD) and creatinine excretion. Heifers were fed one of three diets formulated to produce differences in MCP production: an 85% steam-flaked corn-based diet (SFC); the SFC diet with 1.5% urea (UREA); or a corn milling byproduct-based diet (BYPROD). Spot samples of urine were collected at 0700 and 1700 hours. No urine collection time x dietary treatment interactions were present for any variable. Dry matter intake, ADG, and F:G were poorest with the SFC treatment. Urinary PD:creatinine (PD:C) ratio was greatest with the BYPROD treatment and lowest with the SFC treatment, measuring 0.94, 1.18, and 1.25 for the SFC, UREA, and BYPROD treatments, respectively. Regardless of diet, PD:C was greater with samples collected later in the day, and differences in PD:C due to diet can be observed regardless of collection time.