Induced infectious bovine keratoconjunctivitis: vaccination with whole cell bacterins of Moraxella bovis mixed with Freund's incomplete adjuvant.

Our studies on vaccination against infectious bovine keratoconjunctivitis were extended to include the use of adjuvant bacterins. Seventeen calves were given 2 doses of killed Moraxella bovis mixed with Freund's incomplete adjuvant; 15 calves were given 2 doses of whole cell bacterin without adjuvant. Four weeks later, all vaccinated and non-vaccinated (control) calves were challenge exposed by the conjunctival administration of virulent M bovis. The incorporation of Freund's incomplete adjuvant did not enhance the immunogenicity of M bovis bacterin for protection of calves against infectious bovine keratoconjunctivitis. Results indicated that the use of Freund's incomplete adjuvant does not compensate for a reduction in the number of doses which are required for protective vaccination of cattle.