Serological responses of rams to a Brucella ovis-vitamin E adjuvant vaccine

Rams which were vaccinated at 6-8 months of age with a water-in-oil Brucella ovis-vitamin E adjuvant vaccine had significantly higher serum antibody levels than rams vaccinated with a commercial B. ovis bacterin or B. melitensis Rev 1. The adjuvant vaccine did not cause abscesses at the site of injection as some water-in-oil emulsions do. Two years after vaccination, the vitamin E adjuvant-vaccinated rams had higher antibody level than the other groups. This was most likely due to a secondary response to naturally occurring infection with B. ovis.