A recent trial comparing two 45/20 adjuvant Brucella vaccines.

Two commercially prepared killed 45/20 adjuvant Brucella abortus vaccines were compared, under controlled experimental conditions, with regard to local reactions at the site of injection, serological reactions and immunogenicity. Preliminary trials were carried out in yearling cattle and guinea pigs. Three groups of 13 maiden heifers were involved. One group was vaccinated with Abortox, one group was vaccinated with Duphavac and the third group was kept as unvaccinated controls. Following service, eight, ten and eleven heifers were found pregnant in each group respectively. All were infected at mid-gestation with 15.5 x 10(6) organisms of Brucella abortus S544 (Weybridge 1955). Brucella abortus was recovered from all of the controls, from two of the Abortox vaccinates and from three of the Duphavic vaccinates. The serological reactions are discussed.