Maternal immunity against infectious bursal disease (IBD) in broiler chicks was determined by agar gel diffusion (AGD) technique. The chicks used in this study were of two breeds; Foreign breed and local Iraqi breed. The chicks were hatched from eggs derived from dams previously vaccinated at 18 weeks of age by inactivated oil emulsion IBD vaccine.
The results indicated that the maternal immunity was found on the first day of life in both the breeds. In the first group (Foreign breed) the immunity lasted for 18 days post hatching (DPH) with a titre ranging between log, 0.4/0.1 m! tolog, 1.8/0.1 ml. In the second group (Local breed) the antibody titre were the same like in the first group but the immunity lasted for 14 DPH.