Effects of injectable trace minerals on the immune response to Mannheimia haemolytica and Pasteurella multocida following vaccination of dairy calves with a commercial attenuated-live bacterin vaccine

The objective was to evaluate the effects of an injectable trace mineral (ITM) supplement containing Zn, Mn, Se, and Cu on the humoral and cell mediated immune responses to vaccine antigens in dairy calves receiving an attenuated-live bacterin vaccine containing Mannheimia haemolytica and Pasteurella multocida. Thirty 3-mo-old dairy calves received 2 doses (21 d apart) of an attenuated-live M. haemolytica and P. multocida bacterin vaccine (Once PMH, Merck Animal Health, Summit, NJ), and a 5-way modified-live-virus vaccine (Express 5, Boehringer Ingelheim, Vetmedica, St. Joseph, MO). On the day of primary vaccination, animals were randomly assigned to 1 of the 2 treatment groups (n = 15 per group): ITM (ITM administration) or control (sterile saline injection). Treatments were administered concurrently with vaccinations. Blood samples were collected for determination of antibody titers against M. haemolytica and P. multocida and of antigen-induced proliferation and interferon-γ secretion by peripheral blood mononuclear cells. Serum Se and Mn concentrations were greater (P < 0.05) in the ITM group than the control group after ITM use. Serum end-point antibody titers against both bacteria and interferon-γ secretion by peripheral blood mononuclear cells were not different (P > 0.05) between groups. The use of ITM with bovine respiratory disease vaccines enhanced (P < 0.01) antibody titer fold-change to M. haemolytica. Proliferation of peripheral blood mononuclear cells after P. multocida stimulation was increased (P = 0.03) in the ITM group on d 21 relative to baseline value. In conclusion, ITM administration concurrently with bacterin vaccination improved the immune response to M. haemolytica and P. multocida and might be a valuable tool to enhance dairy calves' response to bovine respiratory disease vaccination.