Aerosol vaccination against Newcastle disease. III. Field experiments in broiler chickens.

Two different aerosol generators were used for aerosol-vaccination of 128,000 broiler-type chickens having moderate to low maternal antibody titers with the B1 and LaSota strains of Newcastle disease virus (NDV). Efficacy of vaccination was evaluated from resistance to challenge with a velogenic strain (Texas GB) of NDV and hemagglutination-inhibition (HI) antibody titers, Both aerosol generators induced adequate immune response at the aperture settings used. There was little detectable benefit from vaccination at 1 day old, but antibody response and resistance to challenge were good from vaccination at 10 and 28 days of age.