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


     

Journal of Dairy Science Vol. 59 No. 4 656-667
© 1976 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 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 Erb, R. E.
Right arrow Articles by Cunningham, M. D.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Erb, R. E.
Right arrow Articles by Cunningham, M. D.

Dietary Urea for Dairy Cattle. II. Effect on Functional Traits1

R. E. Erb, C. M. Brown, Jr., C. J. Callahan, N. J. Moeller, D. L. Hill and M. D. Cunningham

Department of Animal Sciences and Veterinary Science, Purdue University, West Lafayette, IN 47907

ABSTRACT

Rations containing urea were blended and fed free-choice during two trials to compare effects on performance. In Groups 1, 2, and 3, respectively, urea nitrogen replaced about 0, 22, and 45% of plant nitrogen in heifer rations from insemination to mid-pregnancy, 0, 8, and 16% thereafter until 2 wk before calving, and 0, 18, and 36% (0, .9, and 1.8% of ration dry matter) precalving and during lactation. Dry matter of the lactation ration was 44% corn silage, 10% alfalfa bromegrass silage, and 46% concentrate (corn, soybean meal or urea, minerals, and vitamins). Trial 1 started with heifers before first insemination, and Trial 2 started just prior to first calving. Dietary urea had no effect on mastitis or other infections, digestive disorders, ovarian function, services per conception, and birth and survival of calves not aborted. Compared to Group 1, Group 3 had increased abortions of first pregnancy (Trial 1), increased retained placenta at second calving (Trial 2), increased calving intervals (Trial 2), and decreased gestation periods (both trials). Average daily yields of milk, fat-corrected milk, fat, and protein were decreased 8, 7, 6, and 13% in Group 3 compared to Group 1 for four consecutive lactations of Trial 2. Performance by Group 2 was similar to Group 1. It appears that replacement values of urea should be decreased if feeding rates approach 2% of the dry matter in a blended high energy ration fed free-choice.

FOOTNOTES

1 Journal Paper 5329, Purdue University Agricultural Experiment Station.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1976 by the American Dairy Science Association ®.