Microbial Characteristics, Microbial Nitrogen Flow, and Urinary Purine Derivative Excretion in Steers Fed at Two Levels of Feed Intake

Authors

Grant I. Crawford, University of Nebraska-Lincoln
Matt K. Luebbe, University of Nebraska - LincolnFollow
Joshua R. Benton, University of Nebraska-LincolnFollow
Terry J. Klopfenstein, University of Nebraska-LincolnFollow
Galen E. Erickson, University of Nebraska-LincolnFollow

Date of this Version

January 2008

Comments

Published in 2008 Nebraska Beef Cattle Report. Copyright © 2007 The Board of Regents of the University of Nebraska.

Abstract

Ruminally and duodenally fistulated Holstein steers were fed at 40% and 85% of ad-libitum intake. Microbial purine:N ratio did not differ between intake levels, which makes estimating microbial protein easier in production or experimental settings. Urinary purine derivatives (PD):creatinine (PD:C) ratio and microbial CP flow estimated from the duodenum increased with the higher feeding level. Urinary PD:C and duodenal purine flow were related, suggesting that urinary PD:C ratio can be used to estimate relative differences in microbial CP flow.