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


     

Journal of Dairy Science Vol. 78 No. 12 2871-2876
© 1995 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 Grossman, M.
Right arrow Articles by Den Daas, J.H.G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Grossman, M.
Right arrow Articles by Den Daas, J.H.G.

Multiphasic Analysis of Reproductive Efficiency of Dairy Bulls

M. Grossman 1, W. J. Koops 2, and J.H.G. Den Daas 3

1 Department of Animal Sciences, University of Illinois Urbana 61801
2 Department of Animal Husbandry, Agricultural University, PO Box 338 6700 AB Wageningen, The Netherlands
3 Holland Genetics, PO Box 5073, 6802 EB Amhem, The Netherlands

Reproductive efficiency of dairy bulls is usually measured by nonreturn rate. Nonreturn is a compound trait that is a result of two events, conception and gestation, that lead to calving. Nonreturn rates can be used to derive more elementary biological measures for reproductive efficiency, such as conception rate and calving rate, which separately might be more reliable than nonreturn rate itself to evaluate the fertility of a bull or the performance of an AI technician.

The challenge of this study was to examine the decline in nonreturn rate in light of the theory of multiphasic analysis. A multiphasic logistic function was developed to model decline in nonreturn rate by estimating conception rate, calving rate, and characteristics of the first two estrous cycles. The model is illustrated with data on daily nonreturn rates to 120 d.

From the proportion of cows that conceived but failed to complete gestation because of postsignal embryonic death, the model estimates conception rate and calving rate. From the proportion of cows that failed to conceive or that conceived but failed to complete gestation because of presignal embryonic death, the model estimates the proportion of returns, or probability of detecting estrus, duration of nonreturns, and time of maximum decline in nonreturn rate for the first two cycles. Using the proposed model, conception rate and calving rate estimated from daily nonreturn rates might be more reliable for evaluation of performance of an AI technician and fertility of a bull than nonreturn rates at arbitrarily chosen days after insemination.

Key Words: calving rate • conception rate • mathematical model • nonreturn rate

Submitted on August 15, 1994
Accepted on August 17, 1995




This article has been cited by other articles:


Home page
 J AndrolHome page
A. G. Braundmeier, J. M. Demers, R. D. Shanks, R. G. Saacke, and D. J. Miller
Examination of the Binding Ability of Bovine Spermatozoa to the Zona Pellucida as an Indicator of Fertility
J Androl, September 1, 2002; 23(5): 645 - 651.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1995 by the American Dairy Science Association ®.