ABSTRACT
Two field trials carried out on 2,000 broiler chickens showed that chickens vaccinated with the lyophilised Newcastle disease (ND) "F" vaccine at 1, 21, and 42 days were protected when challenged at 14, 35, 56 and 70 days with the virulent strain of Newcastle disease virus (NDV) administered intramuscularly, intranasally, or by contact. A high percentage of the vaccinated birds were protected even though the haemagglutination inhibition (HI) antibody levels were persistently low. Autopsies of the control and vaccinated birds that died from the challenge showed that most of the birds had lesions in the intestines.
Subject(s)
Chickens , Newcastle Disease/prevention & control , Newcastle disease virus/immunology , Vaccination/veterinary , Viral Vaccines/administration & dosage , Administration, Intranasal , Animals , Antibodies, Viral/analysis , Clinical Trials as Topic/veterinary , Dose-Response Relationship, Drug , Freeze Drying , Hemagglutination Inhibition Tests/veterinaryABSTRACT
An Australian strain of Newcastle disease virus, was evaluated for used as a vaccine following its administration by drinking water, aerosol and spray to chickens at 1 and 21 days of age. Haemagglutination inhibition antibody was produced and persisted for 11 weeks. Aerosol vaccination induced higher levels of haemagglutination inhibition antibody than the other methods of vaccination. No respiratory disease was observed following vaccination. Chickens vaccinated by aerosol and spray were fully protected when challenged at 5, 7 and 11 weeks of age with virulent Newcastle disease virus. Mortality of 10 to 30 per cent was observed in chickens vaccinated by drinking water and intranasally following challenge.
Subject(s)
Chickens/immunology , Newcastle disease virus/immunology , Viral Vaccines/administration & dosage , Administration, Intranasal , Administration, Oral , Aerosols , Animals , Antibodies, Viral/analysis , Australia , Newcastle Disease/prevention & control , WaterABSTRACT
Vaccination of chickens with the commercial Newcastle Disease (ND) V4 vaccine at 21 days old or at 21 and 35 days old, stimulated satisfactory and persistent HI antibody levels. The vaccinated chickens were immune when challenged at 49 days old or 77 days old with the virulent strain of NDV administered intramuscularly, intranasally or by contact. Postmortem findings of the non-vaccinated and vaccinated chickens that died from the challenge were recorded.
