Fahey K J, Crooks J K, Fraser R A
CSIRO Division of Animal Health, Animal Health Research Laboratory, Parkville, Victoria.
Aust Vet J. 1987 Jul;64(7):203-7. doi: 10.1111/j.1751-0813.1987.tb15182.x.
The level of maternal antibody to infectious bursal disease (IBD) virus in the circulation of one-day-old layer strain chickens was found to be on average, 45% of the antibody titre in their respective dam, while the minimum ELISA titre which protected against a challenge of 1000 CID50 of virus was 400. Maternal antibody was found to disappear from the circulation of these crossbred chickens with a half-life of 6.7 days. From these data it is possible to estimate the ELISA titre necessary in vaccinated hens to provide the desired duration of passive protection; protection being assessed by an ELISA which measures IBD viral antigen in the bursa of Fabricius following challenge.
