JDS (none)
 QUICK SEARCH:   [advanced]
Year:  Vol:  Page: 

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
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
Google Scholar
Right arrow Articles by Miller, R. H.
Right arrow Articles by Hutchison, J. L.
Right arrow PubMed Citation
Right arrow Articles by Miller, R. H.
Right arrow Articles by Hutchison, J. L.
J. Dairy Sci. 90:1594-1606
American Dairy Science Association, 2007.

Voluntary Waiting Period and Adoption of Synchronized Breeding in Dairy Herd Improvement Herds

R. H. Miller*,1, H. D. Norman*, M. T. Kuhn*, J. S. Clay{dagger} and J. L. Hutchison*

* Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350
{dagger} Dairy Records Management Systems, Raleigh, NC 27603

1 Corresponding author: millerrh{at}juno.com

Voluntary waiting period and adoption of synchronized breeding (ovulation synchronization followed by timed artificial insemination) were characterized from 33 million services of Holsteins and Jerseys in Dairy Herd Improvement herds. Calving month, calving year, and parity had large effects on days to first service for both breeds. Holstein cows that calved during March and April were bred later than those that calved during other months (February and March for Jerseys), whereas cows that calved during September and October were bred earlier. First-parity cows had longer days to first service than did second-parity cows. Herd-year voluntary waiting period was measured as the days postpartum by which 10% of cows had received a first insemination. Median days to reach 10% of cows bred were 55.5 d. Over 65% of herds had 10% of cows inseminated by 60 d postpartum, the voluntary waiting period assumed for national evaluations for daughter pregnancy rate. Herd-years with synchronized breeding at first insemination were identified through {chi}2 analysis based on deviation of observed frequency of first inseminations by day of the week from an expected equal frequency and by the maximum percentage of cows inseminated on a particular day of the week. Herds that were identified as having synchronized breeding had fewer days to first service (17.0), more services (0.16/cow), and fewer days open (9.1) than did herds that were classified as having traditional estrus detection. Synchronized herds also had a standard deviation for days to first service that was only 38% as large as that for herds that bred on observed estrus. Adoption of synchronized breeding for first services steadily increased from 1.9% of herd-years (2% of cows) for 1996 to 19.9% of herd-years (34.9% of cows) for 2005. Procedures for genetic evaluation of daughter pregnancy rate should be examined to determine if herd regimen for reproductive management affects results.

Key Words: voluntary waiting period days to first service synchronization timed artificial insemination

Copyright 2007 by the American Dairy Science Association.