SEFETY AND BFFICACY TESTS OF INFECTIOUS BURSAL DISEASE VARIANT STRAIN VACCINE BK912

There groups of 20-day-old SPF chicks raised in isolators were vaccinated by ocu-lar instillation and oral administration with three batches of IBD BK912 lyophilized vaccinerespectively.Booster was carried out 2 weeks later with the same method.Two weeks afterthe booster,one control group and three vaccinated groups were challenged with 100BID501084A strain.Results showed 100%morbidity for the control group and 100%protectionfor the vaccinated groups.Determination of bursa index as well as protection test reveal thatthe vaccine was safe and did no harm to the bursa.