Fig. 1. (A) Individual serum virus neutralizing antibody titers of calves according to calf age on day 0 of the experiment. Horizontal red line indicates the cut-off level of antibody titers for estimated protection. (B) Geometric means of neutralizing antibodies for calves grouped by 10-day intervals based on calf age at day 0 of the experiment. A linear slope was drawn using these titer values. Horizontal red line indicates the cut-off level of antibody titers for estimated protection. Green color filled area indicates the estimated protection period. (C) Geometric means of neutralizing maternal antibody levels of unvaccinated group. A linear slope was drawn with these titer values. Horizontal red lines indicate the cut-off level of antibody titers for estimated protection. Green color filled area indicates the estimated protection period.
