In spite of numerous vaccines and different vaccination schedules used in the control of Newcastle disease (ND), prevention and control are still a problem. This study evaluated three different ND vaccines. A total of one hundred and twenty, day-old brown pullets obtained from a commercial hatchery in Ibadan, Nigeria were used for the experiment. The birds were randomly assigned into 4 groups in which groups A, B and C were vaccinated on days 1, 21 and 42 of age, while group D served as unvaccinated control. Hitchner B1 (HB1), Clone-30 and F-Strains were used as the primers for the 3 vaccinated groups respectively. Blood samples were collected from birds in each group on vaccination day and assayed for NDV antibody by Haemagglutination-inhibition (HI) test. Twenty five chickens from each group were challenged with virulent Newcastle disease virus (Kudu 113 strain) at 3 weeks after the last vaccination. The mean antibody titres of the chickens of the vaccinated groups at 3 weeks post primary vaccination showed no significant difference. However, a significant difference existed following secondary vaccination with La Sota and Komarov strains at 3 and 6 weeks of age. A good immune response and clinical resistance were observed in group of chickens vaccinated with Hitchner B1 and Clone-30 as primers than those vaccinated using F-strain. Therefore, Hitchner B1 or Clone-30 could be used as primer when vaccinating chickens against Newcastle disease.
Key words: Chickens, Vaccination, antibody, Newcastle disease, Kudu 113 Strain
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