Susceptibility of turkey poults from vaccinated and unvaccinated hens to alcaligenes rhinotracheitis (turkey coryza).

One specific-pathogen-free breeder flock of Beltsville small white turkeys was given two doses of oil-emulsion-adjuvanted Alcaligenes faecalis bacterin 3 months apart, and another flock was left unvaccinated. Progeny from each flock from eggs laid after both first and second vaccination were exposed to the homologous strain (838) of A. faecalis at 1 day of age either experimentally (10(7) colony-forming units intranasally) or naturally (continuous contact with an infected poult) and monitored for 2, 4, or 6 weeks. Progeny from vaccinated hens had substantial resistance to alcaligenes rhinotracheitis compared with progeny from unvaccinated hens; resistance was greatest in progeny from twice-vaccinated hens. Poults from vaccinated hens had improved livability and growth, delayed onset of infection and clinical signs, and a less severe disease process. The results of this study indicate that breeder hen vaccination could be a useful method for providing poults with early protection against alcaligenes rhinotracheitis.