Technical Bulletin

To:All Broiler Parent Clients

Subject: Serotype J Avian Leucosis - Practical On-Farm Control Measures for Broiler Parents.

The following is presented as a check-list of possible measures for the control of the lateral transmission of Avian Leucosis viruses in parent stock. The items are not in any order of priority, their individual importance will vary according to the specific farm and flock circumstances.

1. Optimise cleaning and disinfection in order to place young chicks in as clean an environment as possible.

2. Segregate day-olds from older stock preferably by having all sites single-age.

3. Avoid multi-strain sites and work with the chick supplier to minimise the number of source flocks per site.

4. If possible, pen chicks by flock codes.

5. Avoid handling in the first week and for as long as feasible. In particular, if placement to individual pen by parent flock or ALV-J status has been possible, grading should be left to as late as possible.

6. If carrying out activities where there is a significant risk of faecal and/or blood contamination of operators (e.g. de-beaking) in early life then change gloves and protective clothing between pens. Ideally, throughout rear, sanitise hands and any equipment between pens when bird handling is practised.

7. Review diet and feeding regime to ensure adequate protein intake (serum protein testing at routine blood sampling times may be beneficial). Particular attention must be paid to bird grading (having due regard for the point made in paragraph 3 above) and the management of birds graded as "light" to ensure adequate food intake and avoid competition.

8. Sterilise blood sampling equipment (scalpel or needle) between birds.

9. Consider the use of needle sterilisers for inactivated vaccines (e.g. Sterimatic - we can provide further information on this.).

10. Review vaccination programme:

Avoid Gumboro vaccination before 18 days and avoid the use of hot strain vaccines (Intermediate strains are OK but if Gumboro challenge is believed to be light, PBG at 6 weeks should be adequate).

Ensure that flocks are properly vaccinated for AE

If using live reovirus vaccine use as late as possible.

11. Avoid mating up early. Follow a minimum of 18 weeks of age, 20 if possible.

If you have any queries arising from this please do not hesitate to contact one of us.

Paul McMullin