This research work was conducted to investigate the effects of age, sex and breed on the induction of immune response against experimentally prepared inactivated trivalent (type O, A, and Asia-1) FMD vaccine. Twenty six cattle were divided into four test groups (Group A, B, C, and D; 5 cattle in each group) and one control group (n=6) based on breed (local and cross), age (≤12 months and >12 months), and sex (male and female). Test cattle were vaccinated with the experimentally prepared trivalent FMD vaccine. Pre- and post vaccinated sera from the vaccinated cattle were collected upto 63 days, and the sera were tested using liquid phase blocking enzyme linked immunosorbent assay (LPBE) that was specific for FMD serotypes O, A, and Asia-1. Antibody titers of all the pre-vaccinated serum samples were found to be under protection level. The females were found to be more protected (90%; n=9/10) as compared to males (70%; n=7/10). The titers obtained were statistically analyzed using t–test to observe the effects of age, breed and sex. It was observed that the mean values of antibody titer in cattle aging >12 months against O, A, and Asia-1 serotypes were significant (P<0.05) at 21, 49 and 63 days as compared to the values obtained from the cattle aging ≤12 months. In conclusion, the local female cattle aging >12 months showed better immune response towards trivalent FMD vaccine.

OBJECTIVE To investigate the association of bovine respiratory disease (BRD) or vaccination with serologic response in calves. ANIMALS 94 Holstein calves. PROCEDURES To assess the association between BRD and antibody titers, 38 calves < 3 months old that were treated for BRD were matched with 38 untreated calves. To investigate the effect of vaccination on antibody titers, 24 calves were randomly assigned to be vaccinated against bovine respiratory syncytial virus (BRSV), bovine viral diarrhea virus types 1 and 2, bovine herpesvirus type 1 (BHV1), and parainfluenza virus type 3 at 2 weeks of age (n = 6), 5 weeks of age (6), and both 2 and 5 weeks of age (6) or were assigned to be unvaccinated controls (6). Blood samples were obtained at I, 2, 5, and 12 weeks for determination of serum neutralization antibody titers against the vaccine viruses, bovine coronavirus, and Mannheimia haemolytica. Antibody rates of decay were calculated. RESULTS Calves with initial antibody titers against BRSV < 1:64 that were treated for BRD had a slower rate of anti-BRSV antibody decay than did similar calves that were not treated for BRD. Calves with high initial antibody titers against BRSV and BHV1 had lower odds of BRD than did calves with low initial antibody titers against those 2 pathogens. Vaccination at 2 or 5 weeks of age had no effect on the rate of antibody decay. CONCLUSIONS AND CLINICAL RELEVANCE Clinical BRD and the serologic response of dairy calves were associated with initial antibody titers against BRSV and BHV1. Serologic or clinical responses to viral exposure may differ in calves with low passive immunity.