Newcastle disease (ND) is fatal disease that threatens the poultry production all over the world. ND control strategies based mainly on vaccination. Despite the intensive vaccination programmes that have been implemented for ND control, the outbreaks appear continuously in vaccinated flocks and keep a continuous spread of virus to environment. The field virus
isolates obtained from recent outbreaks in Egypt revealed new strain classified as class II velogenic genotype VII sub genotype d. Although the NDV strains from one serotype APMV-1, there is genetic diversity between different genotypes. In this study, the efficacy of two inactivated NDV vaccines that have been prepared from LaSota (genotype II) and VII d
NDV (genotype VII) strains evaluated using haemagglutination inhibition test on serum obtained weekly from vaccinated chicks to monitor antibody titer induced by the prepared vaccines and also evaluated for protection % in the vaccines received birds that challenged with 106 LD50/0.5 ml I/M at 28 days post vaccination .The protection % was 100 % .this
study indicated that, the different Newcastle disease virus strains used for preparation of inactivated vaccines don't affect the protection of such vaccines against disease signs and mortality.