title: Serological evaluation of precolostral serum samples to detect Bovine viral diarrhea virus infections in large commercial dairy herds.
abstract: The authors propose that screening newborn calves for Bovine viral diarrhea virus (BVDV) antibody prior to colostrum feeding is a useful strategy to detect herds with endemic BVDV infection. In the current study, precolostral serum samples of newborn calves in 2 Minnesota and 2 California dairy farms were examined. Precolostral BVDV antibodies were detected by serum neutralization and enzyme-linked immunosorbent assay in 7.4% (33/446) and 6.2% (32/515) of newborn calves in the California and Minnesota herds, respectively. The serum samples were also tested by reverse transcription polymerase chain reaction (RT-PCR), and BVDV was detected in 1.6% (7/446) and 3.5% (18/515) of newborn calves in the California and Minnesota herds, respectively. The primary advantages of precolostral testing are that calves congenitally infected with BVDV and seropositive at birth represent a larger percentage of calves born than BVDV-viremic calves and that fewer animals would need to be tested with an antibody test than a RT-PCR or antigen detection test to detect endemic BVDV infections at the herd level. Testing for BVDV antibody in calves prior to colostrum feeding detects fetal infections in both late-gestating cows and nonlactating heifers. Precolostral serum antibody detection is not confounded by vaccination and may be a more sensitive screening method than bulk milk RT-PCR and nonvaccinated sentinel calf strategies in large dairy herds.
authors.affiliation: Minnesota Veterinary Diagnostic Laboratory, University of Minnesota, St Paul, MN 55108, USA. sche0201@umn.edu
authors.forename: Jeremy
authors.initials: J
authors.lastname: Schefers
authors.forename: Claudia
authors.initials: C
authors.lastname: Munoz-Zanzi
authors.forename: James E
authors.initials: JE
authors.lastname: Collins
authors.forename: Sagar M
authors.initials: SM
authors.lastname: Goyal
authors.forename: Trevor R
authors.initials: TR
authors.lastname: Ames
mesh_terms: D000818:Animals; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000175:diagnosis*; D001947:Breeding; D002140:California; D002417:Cattle; D003612:Dairying / Q000379:methods; D030241:Diarrhea Virus 1, Bovine Viral / Q000235:genetics / Q000302:isolation & purification*; D030242:Diarrhea Virus 2, Bovine Viral / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D030243:Hemorrhagic Syndrome, Bovine / Q000175:diagnosis*; D008297:Male; D008910:Minnesota; D020133:Reverse Transcriptase Polymerase Chain Reaction