Factors Influencing the Vaccination Programme for Newcastle Disease in Bangladesh: Disease Outbreaks, Haemagglutination-Inhibition Titres and Production under Field Conditions
Keywords:Newcastle disease (ND) virus, Vaccine, Haemagglutination-inhibition (HI) test, Embryo infective dose fifty (EID50)
The study was undertaken to examine the immune response of birds following the present Newcastle disease (ND) vaccination programme by haemagglutination-inhibition (HI) test (Î²-procedure) from three study regions. This study also investigated factors possibly influencing the success of the vaccination programme. Though, those three farms had followed the different vaccination schedules, but using the same ND vaccines. Haemagglutination-inhibition (HI) titres at day-old were lower in Central Poultry Farm, Mirpur than Government Poultry Farms Jamalganj, Joypurhat and Bogra. Birds of these three farms did not persist challenge at day-old, because minimum HI titre for challenge was 24. But after introduction of ND vaccines, the HI titres showed the protective level (>24). The HI titres were lower in Mirpur after introduction of ND vaccines than Joypurhat and Bogra. The EID50 of ND vaccines were determined before introduction to test the potency of vaccines. The embryo infective dose fifty (EID50) of BCRDV (ND-F strain) was 107.67 and the EID50 RDV (ND-â€˜M' strain) was 107.46 EID50. It was done in the specific pathogen free (SPF) embryonating chicken eggs of 9-11 days of incubation. The bird mortality (%) at three different farms was different from week 1 to week 30. The body weight gain of birds at 3 different farms was different. It was also related to hen day egg production percentage. The body weight of birds of the 3 farms was different from week 2 to week 30. The intraocular vaccination of chicks with BCRDV (ND-F strain) at day 5 or day-old followed by vaccination with RDV (ND-M strain) by intramuscular route 8 weeks after primary vaccination and also before laying revaccination with RDV (ND-M strain) by intramuscular route would be a safe and efficient vaccination schedule.
Keywords: Newcastle disease (ND) virus, Vaccine, Haemagglutination-inhibition (HI) test, Embryo infective dose fifty (EID50)