Natural infection of broiler breeder chickens with endemic apathogenic Newcastle disease virus and their subsequent response to vaccination with a live V4 Newcastle disease virus vaccine.
1991
Bell I.G. | Nicholls P.J. | Norman C. | Cross G.M.
Flocks on a commercial farm were monitored for natural infection with endemic lentogenic Newcastle disease virus. Seroconversion was first detected at 17 weeks; peak titres were obtained at 24 weeks; and titres then declined and rose again over months, suggesting cyclic reinfection with the virus. at 54 weeks of age, 6 of 8 flocks were mass vaccinated with live vaccine, by drinking water or by aerosol. Responses showed that flocks with pre-existing natural immunity can be successfully vaccinated by the drinking water route, though not by aerosol. The response was greater in sires than in dams.
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Эту запись предоставил Wolters Kluwer