Immune Response in Chickens After Simultaneous Vaccination Against Newcastle and Gumboro Disease Viruses

In this study the possibility of using simultaneous vaccination against ND, IBD in Sharkia, where the disease is a major problem, was tested beside studying prophylactic vaccination against both diseases. The role ofmAb and their influence on the prophylactic vaccination, mangment,hygiene, disinfection. were evaluated in the literature. On basis of experimental trials and field observation during 2 yearsperiod, results obtained under experimental conditions mentioned could be summarized in the following:1- Results showed that mAb against ND was high and homogeneouslydistributed but those against IBD was comparatively low.2- mAb catabolism for ND lasted 18 day and sometimes <30 day, whilethose of IBD the catabolism was very rapid <7 days. 3- Simultaneous vaccination using dead and live vaccines against bothdiseases resulted in DROP of mAb against ND but their values didn’treach zero. This could not be proved in case of IBD as ·the mAb disappeared in control birds at 7 days.4- Simultaneous revaccination with live vaccine against both diseases at 3week of age resulted in rise of antibody response against both diseasesand challengable protection for at least 35 days of age.