Assessment of decay of infectious bursal disease virus maternal antibodies in layer chicks

Abstract

The breeder flock with a history of 2 live vaccines and 1 infectious bursal disease virus oil emulsion vaccine (IBDV OEV) before point of lay showed high levels of antibodies at 25th week of age which persisted up to 40th week but at a slightly lower level. Uniform levels of antibodies among breeders were not observed. Decay of maternally derived antibodies (MDA) was assessed in different batches of chicks drawn from hatcheries and also chicks reared under field conditions. The decay of MDA was slower up to 10th day of age and subsequently there was a rapid fall of titres at 14th day of age. The maternal antibodies persisted depending on the initial titres of the chicks at day-old. The exposure of the chicks to IBD contaminated environment hastens the decay of MDA.