Innate and Acquired Immune Responses of Colostrum-fed Neonatal Holstein Calves Following Intranasal Vaccination with Two Commercially Available Modified-live Virus Vaccines

Objective: To compare immune responses induced by 2 commercially available vaccines with a bovine herpesvirus type 1 (BHV1) component following intranasal (IN) administration to colostrum-fed calves.

Animals: 90 male Holstein calves (ages, 5 to 14 days).

Procedures: In a randomized complete block design, each calf received 2 mL (1 mL/nostril) of vaccine A (n = 30), vaccine B (30), or saline (0.9% NaCl) solution (30) on day 0. Blood samples were collected for determination of serum anti-BHV1 IgG titer, and nasal fluid (NF) samples were collected for determination of interferon (IFN)-α and IFN-γ concentrations and for secretory IgA titers against BHV1, , and at predetermined times for 42 days after vaccination.

Results: All calves were seropositive for anti-BHV1 IgG, and the mean anti-BHV1 IgG titer did not differ significantly among the 3 groups at any time. Both vaccines induced significant transient increases in NF IFN-α and IFN-γ concentrations. On day 5, mean IFN-α concentration and the proportion of calves with detectable IFN-α concentrations for the vaccine A group were significantly greater than those for the vaccine B and control groups. On day 42, the mean NF anti- IgA titers for both vaccine groups were significantly greater than that of the control group.

Conclusions And Clinical Relevance: Both vaccines induced innate and acquired immune responses in calves with colostral antibodies. The magnitude of the IFN-α response and proportion of calves with detectable IFN-α differed between the 2 vaccine groups. Both vaccines appeared to enhance the IgA response against .