Evaluation of Response to Vaccination for Four Viruses That Contribute to Bovine Respiratory Disease Complex in Angus Cattle

Bovine Respiratory Disease Complex (BRDC) is a devastating problem for the US cattle industry, with estimated losses of greater than $800 million per year. Although it is also one of the most in-depth studied complexes in cattle, it remains elusive in treatment. The objective of this study was to examine response to vaccination on four viruses involved in BRDC (BHV-1, BRSV, BVDV-1, and BVDV-2). Viral neutralizing antibody levels against BHV-1, BRSV, BVDV-1, and BVDV-2 were obtained on greater than 1300 calves for each virus and were measured on a tri-weekly basis.  Calves were vaccinated on week 0, booster vaccinated 3 weeks later, and booster response was measured at week 6. Maternal BVDV-1 and BVDV-2 antibody decay was evaluated between week -3 and 0.  The older the calf, the faster maternal antibody decay occurred. Antibody concentration at initial vaccination for the four viruses decreased as calf age increased. The initial response to vaccination was negative for BVDV-1 and BVDV-2 but positive for BRSV and BHV-1. Response to booster vaccination, overall response, and final antibody titer were positive for all viruses, but initial response to vaccination was negative for BVDV-1 and BVDV-2 and positive for BRSV and BHV-1. Phenotypic correlations between the viruses ranged from strongly correlated (0.668 for BVDV-1 and BVDV-2 overall response) to lowly correlated (0.018 for BVDV-1 and BHV-1 initial response). Phenotypic correlations and inconsistencies in response to vaccination between viruses indicate there may be different mechanisms of genetic control for antibody response between the four viruses.