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


     

Journal of Dairy Science Vol. 75 No. 10 2840-2845
© 1992 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 HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Rankin, T. A.
Right arrow Articles by Lodge, J. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Rankin, T. A.
Right arrow Articles by Lodge, J. R.

Timing of Insemination in Dairy Heifers

T. A. Rankin 1, W. R. Smith 1, R. D. Shanks 1, and J. R. Lodge 1

1 Department of Animal Sciences, University of Illinois, Urbana-Champaign 61801

Data representing 676 AI of 372 virgin dairy heifers during 1984 to 1987 at the University of Illinois were analyzed by analysis of variance to determine the effect of timing of AI on conception rate. Standing to be mounted, bawling, and attempting to mount were the three criteria used for determining the presence of estrus. More than 90% of the observations were conducted by one herdsperson between 0700 and 1600 h daily, Heifers were artificially inseminated with frozen semen from 58 bulls by one of two technicians. Conception rate on first AI was 56%, determined by return to estrus or 33- to 50-d rectal palpation for pregnancy. Conception rate to second and later AI was near 40%. Eighty-six percent of the heifers conceived during the trial. The average interval between first observation of standing estrus and AI was 10.5 h; the range was 15 min to 33 h. The model discussed contained six variables: time interval between first observation of standing estrus and AI (group), breed, she within breed, year bred, season bred, and inseminator. The analysis of variance of conception to first AI showed timing of AI and service sire as the two most significant effects. Conception to first AI was worst when AI occurred 13.5 to 33 h after first observation of estrus. No factors considered were significant sources of variation for second or later AI.

Key Words: dairy heifer • timing • artificial insemination • conception rate

Submitted on October 9, 1991
Accepted on July 2, 1992




This article has been cited by other articles:


Home page
 J DAIRY SCIHome page
N. J. Olynk and C. A. Wolf
Expected Net Present Value of Pure and Mixed Sexed Semen Artificial Insemination Strategies in Dairy Heifers
J Dairy Sci, May 1, 2007; 90(5): 2569 - 2576.
[Abstract] [Full Text] [PDF]

Home page
 J DAIRY SCIHome page
M. T. Kuhn, J. L. Hutchison, and G. R. Wiggans
Characterization of Holstein Heifer Fertility in the United States
J Dairy Sci, December 1, 2006; 89(12): 4907 - 4920.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1992 by the American Dairy Science Association ®.