Antibody profile in laying birds vaccinated with Newcastle disease vaccine, La Sota

Newcastle disease (ND) is endemic in Nigeria and constitutes a major problem to poultry production especially commercial egg production. Despite vaccination of birds, some farmers and other stakeholders still believe that there is shortened protection interval between vaccinations leading to frequent outbreaks. This work studied the antibody profile in vaccinated birds using Newcastle disease vaccine, La Sota (NDVL) with a view to establishing the rise and decline in antibody titre after vaccination and thereby determining the protection interval in our local environment. Two hundred and eighty (280) Shaver brown layers at 78% hen house production were used for the experiment. When their antibody levels were at Geometric Mean Titre of 12.1, they were vaccinated with NDVL through the oral route. On a monthly basis, the antibody titre was determined and 80 birds were taken to a distant location and challenged with a velogenic strain of Newcastle disease virus (NDV). Results showed good protection at 4 weeks, fair protection at 8 weeks and no protection at 12 weeks post vaccination (PV). We therefore recommend that under the Nigerian condition, laying flocks should be revaccinated at 7-8 weeks interval with NDVL