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 Veira, D. M. Articles by Stone, J. B. Search for Related Content PubMed PubMed Citation Articles by Veira, D. M. Articles by Stone, J. B.

Nutrition of the Weaned Holstein Calf. I. Effect of Dietary Protein Level on Ruminant Metabolism¹

University of Guelph³ Guelph, Ontario, Canada N1G 2W1

Abstract

The effect of various dietary crude protein (CP) levels on rumen metabolism was studied with four Holstein calves (avg wt, 146 kg) fitted with ruminal and abomasal cannulae and fed four corn-based diets supplemented with 0, 5, 10 and 15% soybean meal (SBM). The diets contained 10.2, 12.2, 14.1 and 16.1% CP. Apparent rumen digestion of dry matter (DM), organic matter (OM) and starch averaged 43.9, 48.0 and 68.4%, respectively; none of these was affected by diet (P>.05). There was a linear increase in abomasal flow of ammonia nitrogen (N) (P<.01) and residual N (P<.05) as SBM increased in the diet. There was no effect of diet on abomasal flow of bacterial N, Abomasal flow of nonammonia N (g/100 g DM intake) increased in a linear manner (P<.05) from 1.75 at 10.2% CP to 2.07 at 16.1% CP. When protein was greater than 12% of the diet, there was evidence of wastage of protein in the rumen. Bacterial synthesis in the rumen averaged 2.0 g/100 g organic matter apparently digested. There was no apparent effect of rumen ammonia concentration on rate of microbial synthesis in spite of the low levels (<5 mg N/100 ml) observed with the low CP diets. There was a linear increase in serum urea levels before and after feeding as dietary CP increased (P<.001). Volatile fatty acid concentration in the rumen, turnover rate of the fluid phase in the rumen and rumen volume were all unaffected by changes in dietary protein (P>.05).

¹ This research was supported by the Ontario Ministry of Agriculture and Food and by the National Research Council of Canada.

² Present address: Anim. Res. Inst., Agriculture Canada, Ottawa, Ontario K1A 0C6.

³ Dept. of Anim. and Poul. Sci.

This article has been cited by other articles:

				J. Boguhn, H. Kluth, and M. Rodehutscord Effect of Total Mixed Ration Composition on Fermentation and Efficiency of Ruminal Microbial Crude Protein Synthesis In Vitro J Dairy Sci, May 1, 2006; 89(5): 1580 - 1591. [Abstract] [Full Text] [PDF]