Preparation and use of an autogenous bacterin against infectious coryza in chickens.

An experiment was conducted to determine the efficacy of an autogenous bacterin against infectious coryza from a local strain of Haemophilus paragallinarum in Morocco compared with a commercial vaccine. Hens were vaccinated with a single dose or two doses of the bacterin at 15 and 18 weeks of age. Both the autogenous and the commercial vaccine conferred significant protection against experimental challenge (94% and 88%, respectively). A single dose was less protective with both vaccines.