Why some broiler vaccines fail

Researchers at the University of Georgia investigated the possible reasons for frequent vaccine failures when broilers are vaccinated with Arkansas infectious bronchitis vaccine. Their findings are outlined below.

The goal of this project was to understand why Arkansas (Ark) infectious bronchitis vaccines are not effective when delivered by a hatchery spray cabinet. Considering that Massachusetts (Mass) type infectious bronchitis vaccines are effective when given by a hatchery spray cabinet and that Ark vaccines are effective when given by eye drop.

The delivery of the poultry vaccine not the only flaw

Dr Mark Jackwood and Dr Brian Jordan found that although the inefficient nature of delivering vaccines with a hatchery spray cabinet contributes to the problem, the failure of Ark IBV vaccine when delivered by a hatchery spray cabinet was not solely related to the mechanism of delivery but rather to problems inherent in the Ark vaccine.

Ark vaccines contain multiple virus subpopulations. One of the minor virus subpopulations in the vaccine is responsible for infecting the chicks and inducing immunity. A sufficient amount of this minor subpopulation in the Ark vaccine capable must be given for the vaccine to be effective.