Relationship Between Metabolizable Protein Balance and Feed Efficiency of Steers and Heifers

Authors

Grant I. Crawford, University of Nebraska-Lincoln
Stephanie A. Quinn, University of Nebraska-Lincoln
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

Two individual feeding experiments were analyzed for the relationship between metabolizable protein (MP) balance and feed efficiency (G:F) in individually-fed steers and heifers. In Experiment 1, 29 crossbred steers were fed steam-flaked corn (SFC)-based diets containing either 0% or 1.2% urea (DM basis). In Experiment 2, 75 crossbred heifers were fed SFC-based diets with either 0% or 1.5% urea. The NRC (1996) MP model was used to determine individual degradable intake protein and MP balances. In both experiments there was a negative relationship within treatment between MP balance and G:F. These results were not expected, and three potential causes were proposed: conversion of MP to net protein; ruminal pH; and/or residual feed intake.