A growth medium for the production of a bacterin for immunization against infectious coryza

A serum-free modified Casman broth medium was developed to grow Haemophilus gallinarum to titers of 10-8 organisms per ml. Formalin-inactivated bacterins prepared form the broth culture were used to immunize chickens. A single dose of bacterin containing adjuvant protected 6 of 7 chickens against a homologous challenge 4 weeks postvaccination. A second dose given 3 weeks after the first offered no better protection than a single dose.