An experimental turkey rhinotracheitis (TRT) infection in breeding turkeys and the prevention of its clinical effects using live-attenuated and inactivated TRT vaccines.

The experimental inoculation of 38-week-old turkey hens with a pool of field isolates of turkey rhinotracheitis virus (TRTV) induced a marked respiratory infection and a substantial drop in egg production. Administration of a live-attenuated TRT vaccine at 1 week of age did not protect the layers against respiratory infection, but provided good protection against the effects of challenge on laying performance. However, a combination of live priming followed by injection of inactivated vaccine provided excellent protection against both respiratory infection and drops in egg production.