Evaluation of two vaccination programs to control infectious bursal disease in commercial broilers

An experimental study was carried out to compare protection induced by two infectious bursal disease [IBD] vaccination programs in commercial broilers. Chickens inoculated with live vaccine at 7 and 21 days old were protected against mortality but clinical signs of IBD were noted after challenge at 28 and 35 days old. Chickens inoculated with both live vaccine [at 7 and 21 days old] and inactivated vaccine [at 8 days old] were better protected against challenge at 28 and 35 days of age. This vaccination program protected challenged chickens against both mortality and clinical IBD signs. However, the bursa: body weight ratios were lower than those of the control birds [P < 0.05]