JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Journal of Dairy Science Vol. 72 No. 2 462-470
© 1989 by American Dairy Science Association ®
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Xin, Z.
Right arrow Articles by Hemken, R. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Xin, Z.
Right arrow Articles by Hemken, R. W.

Effect of Reactivity Rate and Particle Size of Magnesium Oxide on Magnesium Availability, Acid-Base Balance, Mineral Metabolism, and Milking Performance of Dairy Cows1

Z. Xin2, W. B. Tucker and R. W. Hemken

Department of Animal Science, University of Kentucky, Lexington 40546

ABSTRACT

Four ruminally fistulated Holstein cows were arranged in a 4 x 4 Latin-square design. Treatments consisted of a control diet and three diets containing 4% MgO (DM basis) with increasing reactivity rates (A, B, C). Diets contained corn silage and concentrate at a 40:60 ratio (DM) and were fed at 95% of ad libitum intake. Total acid-consuming capacity and solubility of MgO in vitro paralleled particle size and agreed with the solubilities in the rumen. Milk fat percentage, but not milk yield, was increased by all three MgO diets. Ruminal pH was elevated by the MgO diets across all 8 h postfeeding. MgO, reactivity A diet tended to increase ruminal acetate, total VFA production, milk yield, milk fat yield, and milk fat percentage. Effect of time postfeeding on acetate and propionate production was significant; 2 to 6 h postfeeding was the period most responsive to the diets. No significant influence on blood acid-base balance was observed. On the basis of urinary excretion of Mg, MgO sources with smaller particles are more available to cattle. Both Ca and CI metabolism appeared to be affected by reactivity rate of MgO.

FOOTNOTES

1 This manuscript (87-5-270) is published with the approval of the Director of the Kentucky Agricultural Experiment Station.

2 Present address: Animal Science Department, Oklahoma State University, Stillwater 74078.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1989 by the American Dairy Science Association ®.