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Assessment of voluntary waiting period and frequency of estrus synchronization among herds

Assessment of voluntary waiting period and frequency of estrus synchronization among herds R.H. Miller, 1, * H.D. Norman, 1 M.T. Kuhn, 1 and J.S. Clay 2 1 Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350

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Assessment of voluntary waiting period and frequency of estrus synchronization among herds

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  1. Assessment of voluntary waiting period and frequency of estrus synchronization among herds R.H. Miller,1,* H.D. Norman,1 M.T. Kuhn,1 and J.S. Clay2 1Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350 2Dairy Records Management Systems, Raleigh, NC Abstr. W172 INTRODUCTION • New reproductive management regimes adopted in recent years • Synchronization protocols (ES) • Timed insemination • Voluntary waiting period (VWP) of 60 d assumed by USDA for genetic evaluation of pregnancy rate • Actual herd VWP and frequency of ES relative to traditional estrus detection need to be examined METHODS CONCLUSIONS VWP Determination • Increase in mean DFS from 89 d in 1995 to 94 d in 1998 and then slight decrease • Within herd, reasonably consistent herd means for DFS from year to year (correlation = 0.67) • 10% of cows inseminated before 60 DIM for 70% of herds • 60-d VWP assumed by USDA for calculating pregnancy rate is conservative • Increase in VWP since 1995, but recent moderation ES Herd Identification • Strong trend toward ES/timed AI regimes relative to traditional estrus detection • Steady increase from 0.9% in 1995 to 7.1% in 2001 in relative frequency of ES regimes (probable and ES) • Fewer DFS (16.4 d) and days open (9 d) for ES herds than for herds with traditional estrus detection but more services per cow (0.18) OBJECTIVES • Determine variation in DIM at first service after calving (DFS) among and within herds to assess consistency of VWP • Identify ES herds with timed insemination and compare DFS and number of services between ES herds and those with traditional estrus detection RESULTS DATA • 5.55 million lactation records (DRMS, AgSource) • Inseminations from 1995 through August 2002 • Identified service sires • Holsteins and Jerseys • Pregnancy status unknown • 2529 herds on continual test from 1995 through 2001 • Mean DFS and cows per herd FUTURE RESEARCH • Studies underway to determine if reproductive regime should be considered in genetic evaluations of pregnancy rate

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