Comparison of Rumen Undegradable Protein Content of Conventional and Organic Feeds

Authors

Elizabeth A. Schumacher, University of Nebraska at Lincoln
Galen E. Erickson, University of Nebraska - LincolnFollow
Hannah C. Wilson, University of Nebraska-LincolnFollow
J. C. MacDonald, West Texas A&M University & University of Nebraska at LincolnFollow
Andrea K. Watson, University of Nebraska at LincolnFollow
Terry J. Klopfenstein, University of Nebraska at LincolnFollow

Date of this Version

2020

Citation

The Board Regents of the University of Nebraska. All rights reserved.

Comments

2020 Nebraska Beef Cattle Report

Abstract

Knowledge of a feed ingredient’s protein content and degradability is important in formulating diets for growing cattle. However, there are limited data on protein composition and digestibility of feeds produced in an organic production system. Two studies were conducted using an in situ mobile bag procedure to compare feeds raised in organic and conventional production systems for rumen undegradable protein (RUP) content and digestibility. No differences were observed for RUP content between organic or conventional sources for dehydrated alfalfa, field peas, or expeller pressed soybean meals. Solvent extracted soybean meals were lower in RUP content than expeller pressed soybean meals. Digestibility of RUP was lower for conventional dehydrated alfalfa compared to organic dehydrated alfalfa in Experiment 1 but not in Experiment 2; no other differences in RUP digestibility were observed between conventional and organic feeds. Expeller pressed soybean meals were consistently highest in digestible RUP as a percent of DM with the exception of SoyPass, a soybean meal treated to increase RUP content. These data suggest that feeds produced in organic or conventional systems are not different in RUP content or digestibility and that processing method appears to have greater effect on protein degradability than the production system.