A comparison of three different regimens of infectious bursal disease vaccination in chickens.

Five days old progeny chicks from breeders which have received primary and booster doses of live infectious bursal disease vaccine, demonstrated precipitating antibodies unlike progenies from single dose vaccinated breeders. All chicks from the two different groups of breeders were however seronegative at 22 days of age, despite vaccination at 7 or 14 days of age. Post vaccination seroconversion was first noticeable at 32 days in the group of chicks vaccinated at 7 days. Post challenge mortalities was significantly lower (P less than 0.05) and organ lesions very significantly minimized (P less than 0.01) in 7 day old vaccinated group than in 14 or 28 days old vaccinated chicks. These results showed that early (7 days) IBD Vaccination was superior to vaccination at 14 or 28 days, in terms of antibody response and protectivity against mortalities and bursal lesions.