Influence of Maternal Antibody on the Efficacy of Newcastle Disease Vaccination in Broilers

Abstract

The half-life of maternal antibody (mAb) titres against Newcastle Disease Virus (NDV) were estimated in order to trace its likely declining pattern and the influence on the efficacy of vaccination in broiler chicks. Our study was also conducted to compare two vaccination regimens with live and inactivated NDV vaccine. For this purpose, ninety day-old broiler chicks with known NDV vaccination history of parent stock were randomly allocated into three groups (I) unvaccinated control, (II) Live NDV vaccine, and (III) Live + Inactivated NDV vaccine. Haemagglutination-inhibition (HI) antibodies were determined in the pre- and post-vaccination sera of the experimental chicks. The results indicated that the unvaccinated group showed higher level of mAb against NDV at day 1 with HI antibody titre (Log2) 9.32 which was maintained up to 7 days of age (8.11) and gradually declined with no measurable antibodies of maternal origin after day 14, signifying the initiation of Newcastle Disease (ND) vaccination at 7 days of age. The vaccinated Group II and III revealed significantly higher HI titre at day 14 (11.52, 12.42), day 21 (12.95, 13.22), day 28 (11.63, 12.18) and day 35 (13.31, 13.39) than the unvaccinated control group I. Moreover, there is no significant difference in humoral immune response among both the vaccinated groups. Thus, our study suggests the use of live NDV vaccines for ND prevention in commercial broiler farming over the inactivated NDV vaccines which demands a withdrawal period before slaughter and its economic implication due to additional cost. This study also indicated that the half-life values of mAb and its effect should be considered while customizing an effective vaccine regimen.