Abstract
The immune responsiveness to infectious bursal disease virus (IBDV) in four native and crossbred chicken lines was compared. ELISA IBDV antibody titers in hen serum samples, yolk from matched eggs and sera from matched 1-day-old chicks from each chicken line with an identical vaccination program were measured, and plotted. There was considerable variation between lines in the measured IBDV specific antibodies, in vaccinated parent hens and in the amounts of inherited maternally derived antibodies in both yolk and progeny chicks. Differences in ratios of the inherited antibody level from hen to 1-day-old chicks were also found among different chicken lines. Breed differences in regressions of IBDV antibody levels in yolk to that of hen or progeny chicks’ sera were also found, so prediction of serum titer of hen and/or progeny chicks from yolk are varied among chicken lines.