Resumen de Association of bovine respiratory disease or vaccination with serologic response in dairy heifer calves up to three months of age

M. Clair, Ken Leslie, Sandra M. Godden, Douglas C. Hodgins, Kerry D. Lissemore, Stephen J. LeBlanc

• Association of bovine respiratory disease or vaccination with serologic response in dairy heifer calves up to three months of age M. Claire Windeyer DVM, DVSc; Ken E. Leslie DVM, MSc; Sandra M. Godden DVM, DVSc; Douglas C. Hodgins DVM, PhD; Kerry D. Lissemore DVM, DVSc; Stephen J. LeBlanc DVM, DVSc Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON NIG 2WI, Canada. (Windeyer, Leslie, Lissemore, LeBlanc); Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108. (Godden); Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON NIG 2WI, Canada. (Hodgins) Dr. Windeyer's present address is Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.

  Address correspondence to Dr. Windeyer (c.windeyer@ucalgary.ca).

  OBJECTIVE To investigate the association of bovine respiratory disease (BRD) or vaccination with serologic response in calves.

  ANIMALS 94 Holstein calves.

  PROCEDURES To assess the association between BRD and antibody titers, 38 calves < 3 months old that were treated for BRD were matched with 38 untreated calves. To investigate the effect of vaccination on antibody titers, 24 calves were randomly assigned to be vaccinated against bovine respiratory syncytial virus (BRSV), bovine viral diarrhea virus types 1 and 2, bovine herpesvirus type 1 (BHV1), and parainfluenza virus type 3 at 2 weeks of age (n = 6), 5 weeks of age (6), and both 2 and 5 weeks of age (6) or were assigned to be unvaccinated controls (6). Blood samples were obtained at I, 2, 5, and 12 weeks for determination of serum neutralization antibody titers against the vaccine viruses, bovine coronavirus, and Mannheimia haemolytica. Antibody rates of decay were calculated.

  RESULTS Calves with initial antibody titers against BRSV < 1:64 that were treated for BRD had a slower rate of anti-BRSV antibody decay than did similar calves that were not treated for BRD. Calves with high initial antibody titers against BRSV and BHV1 had lower odds of BRD than did calves with low initial antibody titers against those 2 pathogens. Vaccination at 2 or 5 weeks of age had no effect on the rate of antibody decay.

  CONCLUSIONS AND CLINICAL RELEVANCE Clinical BRD and the serologic response of dairy calves were associated with initial antibody titers against BRSV and BHV1. Serologic or clinical responses to viral exposure may differ in calves with low passive immunity.