PSV-A-2 - Evaluation of Immune Performance of Calves Born to Cows Vaccinated with a Lifetime Regimen of a Modified-live or Killed Viral Vaccine When Challenged with Bovine Viral Diarrhea Virus

Abstract: Vaccination is the most effective way at preventing bovine viral diarrhea virus (BVDV) infection. Maternal antibodies from colostrum provide immunoglobulins to stimulate the naïve immune system of calves, but these wane within the first 3 months of life. Limited information is available on the quality of colostrum influenced by vaccines, and their subsequent calf protection against BVDV. The objective of this study was to evaluate calf performance against BVDV after consumption of colostrum from cows vaccinated with either a killed viral (KV, n = 7) or modified-live viral vaccination (MLV, n = 9) against BVDV. Calves were weaned at approximately 140 days of age and intranasally challenged with BVDV strain 1373. Clinical scores were evaluated twice daily for 28 days, and blood samples were collected on day -2, 0, 3, 6, 8, 10, 14, and 28 post-infection (dpi) for evaluation of complete blood counts, virus isolation, and metabolites. Colostrum IgG was similar between treatment groups (P = 0.75). Calves that were born to KV cows had increased leukocyte and lymphocyte concentrations compared to MLV calves (P ≤ 0.03). Calves born to MLV cows tended to have higher clinical scores, including higher temperatures, and nasal discharge (P = 0.08). Overall, metabolites were unaffected by treatment (P ≥ 0.8), however, metabolites did differ by dpi. Serum urea nitrogen was lowest at dpi 8 (P = 0.02) and glucose was reduced from dpi -2 through d 14 (P < 0.001). Non-esterified fatty acids were elevated through dpi 14 (P < 0.0001) and haptoglobin peaked on dpi 10 (P < 0.0001). Metabolites were altered by the viral challenge and indicate the nutritional status of the animal was shifted to support the immune response. Overall, vaccination treatment of the cow had little impact on the calf’s ability to mount an immune response.