Effects of injectable trace minerals (Se, Zn, Cu, and Mn) administration on the immune response elicited by primary intranasal modified-live virus vaccination in dairy calves.

The objective was to determine the effects of injectable trace minerals (ITM, containing Se, Cu, Zn & Mn) administered at the time of primary intranasal (IN) modified-live virus (MLV) vaccination of young dairy calves on the serum neutralizing antibody (SNA) titers to Bovine herpes virus 1 (BHV1), Bovine respiratory syncytial virus (BRSV), and Bovine Parainfluenza type 3 virus (BPI₃V); cytokine expression in peripheral white blood cells, and BHV1-specific IgA titers in nasal secretions following the vaccination. A total of 60 calves (1 month old) were administered an IN MLV vaccine containing BHV1, BRSV, BPI₃V (Inforce 3^®) and randomly assigned to one of two experimental groups: ITM (n = 30; Multimin^®90, containing Se, Cu, Zn, and Mn) or SAL (n = 30; sterile saline). There was a consistent decay in virus-specific SNA titers in both groups. Calves with ITM had significantly greater BRSV-SNA titers on day 14 (p = 0.045), and day 28 (p = 0.028) than SAL calves. There was a significant increase in BHV1-specific IgA in nasal secretion in both groups, without significant difference. In conclusion, IN vaccination of dairy calves with high levels of maternally derived SNA did not produce a significant increase in SNA titers to the vaccine viruses but did stimulate a significant BHV1-IgA response in nasal secretions. Supplementation with ITM was associated with a delayed decrease of BRSV-SNA titers on days 14 and 28 after primary vaccination. Administration of ITM was also associated with lower clinical scores and respiratory disease morbidity and mortality. Treatment with ITM did not affect SNA titers to BHV1 and BPI3V or the BHV1-specific IgA level in nasal secretions.