Figure 1: Longitudinal IFN-γ response in vaccinated and non vaccinated calves: In vaccinated calves, IFN-γ response was seen to increase starting from week 2, attaining its peak at 4th week post vaccination. Then it started to drop starting from week 4 until week 13 after which it attained the steady level. The mean of IFN-γ response was significantly (tcal=2.85; P<0.05) higher in vaccinated (Mean± SEM, 0.205 ± 0.018) group than in non-vaccinated group (Mean ± SEM, 0.168±0.008) starting from week 2 to week 13.