HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Roffler, R. E. Articles by Satter, L. D. Search for Related Content PubMed PubMed Citation Articles by Roffler, R. E. Articles by Satter, L. D.

Relationship Between Ruminal Ammonia and Nonprotein Nitrogen Utilization by Ruminants. II. Application of Published Evidence to the Development of a Theoretical Model for Predicting Nonprotein Nitrogen Utilization¹

Department of Dairy Science, University of Wisconsin, Madison 53706

ABSTRACT

Results from published experiments dealing with several aspects of nitrogen utilization by ruminants were used to test the concept of zero utilization of nonprotein nitrogen under conditions where more ammonia (>5 mg ammonia nitrogen/100 ml) is in the rumen than can be converted to microbial protein. Results from experiments where the flow of non-ammonia nitrogen to the abomasum of sheep was measured indicate that when urea was the source of supplemental nitrogen, a constant quantity of amino acids reached the abomasum for all rations ranging from 10 to 23% crude protein. From growth studies, addition of nonprotein nitrogen to low protein, high energy rations caused an improved rate of gain. Additions of nonprotein nitrogen to rations resulting in predicted ruminal ammonia concentrations greater than 5 mg ammonia nitrogen/100 ml rumen fluid were without benefit. From lactation studies, nonprotein nitrogen supplementation did not improve milk production if the ration contained more than 12.5% crude protein prior to supplementation or if the predicted ruminal ammonia concentration was greater than 4 mg ammonia nitrogen/100 ml rumen fluid. The importance of the amino acid requirement of the animal as well as the composition of the ration in designing and evaluating nitrogen supplementation studies is discussed.

¹ Research supported by the College of Agricultural and Life Sciences, University of Wisconsin, Madison.

This article has been cited by other articles:

				A. R. J. Cabrita, A. J. M. Fonseca, R. J. Dewhurst, C. V. P. Sampaio, M. F. S. Miranda, G. N. S. Sousa, I. M. F. Miranda, and E. Gomes Nitrogen Supplementation of Corn Silages. 1. Effects on Feed Intake and Milk Production of Dairy Cows J Dairy Sci, December 1, 2003; 86(12): 4008 - 4019. [Abstract] [Full Text] [PDF]