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 Dawson, J. R. Search for Related Content PubMed Articles by Dawson, J. R.

The Breeding Efficiency of Proved (Aged) Sires

Bureau of Dairy Industry, United States Department of Agriculture

ABSTRACT

Detailed service records of 20 proved sires used in 8 branch experiment station dairy herds are presented and the fertility of these sires after 5 years of age is expressed by the percentage of services to fertile cows that resulted in conceptions. Extra services and services to infertile cows are given separately. The data were tabulated and analyzed from the standpoint of (1) the relative fertility of the individual sires, (2) the effect of advancing age on fertility, (3) the effect of frequency of service on fertility, (4) the effect of season of the year on fertility, and (5) the effect of moving sires on their fertility.

Because of the extreme and inconsistent variation in fertility exhibited by individual sires on all phases included in this study, it is apparent that averages are of little value for application to individual sires.