Serological patterns in broiler parent chickens in the U.K.

Broiler parent chickens are intensively vaccinated for one or more of the following purposes :

1. To protect the parents themselves against mortality and morbidity during rear and during production.

2. To provide passive protection to the progeny by transfer of antibodies in the yolk.

3. To reduce or eliminate the transmission of pathogens to the progeny.

Serological monitoring of the response to vaccination and/or field challenge is routinely practiced as a guide to how well the above objectives are being met. In deciding the details of a specific monitoring programme the following factors will usually be taken into account :

1. Historical data on uniformity of response both within and between flocks.

2. Vaccination programme in use. The more vaccines are in use and the more operations which are being carried out on the same day then the greater the need will be to monitor response.

3. The economic consequences of not detecting a flock with a poor vaccinal response or which has become infected with an unwanted pathogen.

Most data presented here represent the results of either routine monitoring, or of investigation of particular disease problems, during the period January 1993 to September 1994. No data have been excluded except for records for which the age of the birds was not informed or recorded. The number of samplings carried out for individual flocks varied according to company policy and individual circumstances.

Detailed information on Specific Diseases: