A prospective field study in heifers from birth to first breeding was undertaken on two commercial dairies to assess the effect of bovine viral diarrhea virus (BVDV) congenital and post-natal infection (PNI) on fertility. A high BVDV Type 2 antibody titer (1:4096) at 10 months of age was associated with 32 more days to conceive, compared with a low titer (1:128). Conversely, infection with BVDV by 5-6 months of age and high BVDV Type 2 titers 1 month before conception or breeding was associated with improved fertility. Heifers with evidence of congenital BVDV infection had lower fertility than non-infected heifers (15-42 days longer time-to-first AI), which depended on BVDV Type 2 titers at 10 months of age. Neospora caninum infection was associated with additional services per conception (SPC) and Leptospira interrogans infection was associated with a delay in the time-to-first breeding. It appears that under field conditions, the effect of subclinical BVDV infection on subsequent heifer fertility may be due to a complex of interrelationships among multiple BVDV infections that depend on the type and timing of infection relative to reproductive development and events.
|Original language||English (US)|
|Number of pages||15|
|State||Published - Apr 15 2004|
Bibliographical noteFunding Information:
Supported by in part by the Graduate Group in Epidemiology, University of California, Davis, Austin Eugene Lyons scholarship, USDA NRI Competitive Grant No. 980-2517, and USDA Formula Funds. The authors thank Dr. Wesley Johnson for statistical advice, Dr. Pete Kistler, Dr. Connor Jameson, Pam Curtis and Mary Benzinger for assistance in sample and data collection, Doug Van Beek and Phil Vannette for access to herds, and the Immunology and Virology laboratories of the California Animal Health and Food Safety Laboratory for sample testing.
- Neospora caninum