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 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 Robinson, P. H. Articles by Kennelly, J. J. Search for Related Content PubMed Articles by Robinson, P. H. Articles by Kennelly, J. J.

Influence of Intake of Rumen Undegradable Protein on Milk Production of Late Lactation Holstein Cows

Department of Animal Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5

ABSTRACT

Twenty Holstein cows, in late lactation, were assigned to five equal groups in an orthogonal design to determine effects of a rapidly rumen degraded protein source (canola meal) low in estimated rumen undegradable protein substituted for a slowly rumen degraded protein source (corn gluten meal) high in rumen undegradable protein on feed intake, milk production, and milk composition. Cows were fed total mixed rations based upon barley silage, haycrop silage, barley grain, and supplemental protein in three 4-wk periods, subsequent to a 4-wk covariate period. In situ rumen incubation of extreme diets and estimation of intermediate diets indicated that all diets exceeded Agricultural Research Council (United Kingdom) recommendations for rumen degradable and undegradable protein as well as NRC recommendations for rumen degradable protein. However, two to four diets, dependent upon assumed ruminal turnover rates, did not meet NRC recommendations for undegradable protein. Dry matter intake and milk yield were not influenced by substitution of canola meal with corn gluten meal to increase dietary undegradable protein content. Daily yield and milk percent of lactose, fat, and protein were not influenced by substitution. Results do not support NRC recommendations to supplement diets based upon these ensiled forages and barley grain for late lactation cows with protein sources resistent to rumen degradation. Results broadly support lower amounts of rumen undegraded protein recommended by the Agricultural Research Council.

This article has been cited by other articles:

				I. R. Ipharraguerre and J. H. Clark Impacts of the Source and Amount of Crude Protein on the Intestinal Supply of Nitrogen Fractions and Performance of Dairy Cows J Dairy Sci, May 1, 2005; 88(e_suppl_1): E22 - E37. [Abstract] [Full Text] [PDF]