Aerosol administration of Newcastle disease vaccines at one day of age.

Newcastle disease vaccines were administered at one day of age by 3 general procedures: 1) discharge of a vaccine aerosol over chicks confined in an enclosed space, 2) aerosol adminstration in a poultry house, 3) a commercial device which emits a fine spray into the nasopharynx while the chick is being debeaked. From this work the following conclusions have been drawn: 1) All 3 methods are of some value with respect to the development of antibody titers and resistance to challenge. 2) The efficacy is universely proportional to the maternal antibody titer. 3) Aerosol vaccination into an enclosed air space is superior to the other methods tested. 4) Day-old vaccination is useful primarily in conferring some early resistance until a subsequent aerosol vaccination at 9-14 days of age confers additional protection. Other important factors include strain of vaccine, vaccine titer, the nature of the diluent, and site of the aerolized particles.