Laboratory investigations on the use of an inactivated IBDV-oil emulsion vaccine in commercial layer chicks. I-protectiveness of partial doses in maternally immune chicks

ABSTRACT

Three simultaneous experiments were carried out to investigate the efficacy of partial doses [1/5 and 2/5 field doses] of an oil emulsion vaccine [OEV], given either alone or in combination with live vaccine at 1 and 7 days, in protecting experimental chicks against very virulent infectious bursal disease virus [vvlBDV]. Variable protection results were obtained and attributed not only to vaccination scheme but also to the high levels of maternal antibodies but OEV seems to play a role in their depletion rate as measured by Elisa. Work is in progress to investigate the efficacy of full dose of OEV on the immune response and depletion rate of maternal antibodies