Total Ig [IgM + IgG] levels against S. suis serotype 2 in piglets as determined by ELISA. Piglets were vaccinated with the equivalent to 109 CFU/mL of S. suis strain P1/7 bacterin formulated either with Alhydrogel® (A), Emulsigen®-D (B), Quil-A® (C), Montanide™ ISA 206 VG (D), Montanide™ ISA 61 VG (E), or Montanide™ ISA 201 VG (F). The 1st dose was given at 3 weeks of age and the 2nd dose at 5 weeks of age (red arrows). Each vaccine formulation group of vaccinated piglets (n = 10) had a corresponding placebo group of piglets (n = 10). Antibody titers for individual piglets are shown with horizontal bars representing mean ± SEM. Values significantly different are shown in the graph with the corresponding P-value.