Abstract:
A polyvalent alum-precipitated vaccine containing Pasteurella multocida (Lehmann & Neuman, 1899) types A and D and four serotypes of Pasteurella haemolytica (Newsom & Cross, 1932) produced a sound immunity in mice and sheep to challenge with the homologous strains of P. multocida. The vaccine also stimulated a marked increase in the haemagglutination titres and passive protection values of the serum to the homologous strains of P. multocida. The antibody response to the P. haemolytica strains was poorer but possibly sufficient to contribute to an increase in resistance to infection.