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 Google Scholar Google Scholar Articles by Jorgensen, N. A. Articles by Schultz, L. H. Search for Related Content PubMed Articles by Jorgensen, N. A. Articles by Schultz, L. H.

Ration Effects on Rumen Acids, Ketogenesis, and Milk Composition. I. Unrestricted Roughage Feeding^{1, 2,}

Department of Dairy Science, University of Wisconsin, Madison

ABSTRACT

Two trials, with 12 cows each, using a 56-day comparison period, were used to investigate the effect of feeding normal levels of hay and concentrates in various forms and combinations on rumen volatile fatty acids, blood ketone and sugar levels, and milk production and composition. In both trials, rations containing pelleted hay or pelleted corn produced the following changes: (1) Lower milk fat test. (2) Lower percentage of rumen acetic acid. (3) Higher percentage of rumen propionic acid. (4) Increased total concentration of rumen acids. (5) Increased blood sugar levels.

The feeding of pelleted corn tended to increase blood ketone bodies, whereas feeding pelleted hay reduced them. Feeding pelleted hay once a day counteracted the ketogenic effect of pelleted corn, whereas feeding a combined pellet, 50% hay-50% corn, had the same ketogenic effect as pelleted corn. An increase in total rumen acids with more butyrate to be metabolized would suggest butyrate to be the ketogenic agent. The high ketone levels did not prevent depression of milk fat test. The depression in milk fat test was not corrected when feeding 20 lb of long hay/day with pelleted corn.

¹ Published with the approval of the Director of the Wisconsin Agricultural Experimental Station.

² These data are part of a thesis presented by the senior author in partial fulfillment of the requirements for the degree of Master of Science, University of Wisconsin.