摘要
A study on infectious bursal disease virus(IBDV)on chickens of Cobb-500 strain broiler breed at Thakurgaon district of Bangladesh was performed.The protective antibody was measured on one day old chicks(DOC)and post-vaccinated(PV)flocks up to 75 weeks by indirect enzyme linked-immunosorbent assay(I-ELISA).The assays have included five flocks with vaccination historic against IBDV contained 45,000 birds with age ranging from DOC to 75 weeks,just before culling.Maternally derived antibody(MDA)mean titer(MT)ranged from 3,395 to 5,184.The antibody from serum samples(N=92 per flock)were titer tested by I-ELISA at age 14 d,5,8,23,50 and 75 weeks of each vaccinated flock.Antibody titer level gradually decreased before vaccination.Vaccination done by intermediate plus vaccine resulting titers level was increased and stayed at the same level.The antibody MT at the 14th day was 500,which supported Deventer method.The protective antibody MT was declined at growing,laying,mid laying and last stage of laying groups.So MDA titer was enough in offspring that could protect birds easily.
