Sheep scab is once again “notifiable” under the Sheep Scab (Scotland) Order 2010. It is currently considered the most contagious disease of sheep in Britain. Mainly transmission is directly from sheep to sheep however the scab mites can survive off sheep for 16 days, living on fences, bushes, trees and equipment. Effective fencing must also be maintained in order to prevent contact with neighbouring sheep that may be carrying scab mites.
Scab will come onto a farm with any sheep moving on after purchase or returning from grazing. It is wise to assume all sheep arriving on the farm could be infected and therefore should be injected or dipped with an appropriate product, and kept away from the main flock until at least two weeks after the treatment has been completed. All animals on the farm should be checked for scab in the spring and treated if required.
If you suspect sheep to have scab it is important to have this diagnosis confirmed by your vet who will take skin scrapings and examine them under the microscope at the practice. If mites are present we will inform the local Animal Health Office who will place temporary movement restrictions until treatment is completed. It is also advisable to warn your neighbours that scab has been diagnosed so that they can treat their flock at the same time. Please contact us to find the most appropriate treatment for your flock.
Pour-ons, jetters and showers are generally considered to be ineffective for control or treatment of scab.
Organophosphate dips may be used and a single application of diazinon will provide approximately 4 weeks protection.
Injections of moxidectin (Cydectin or Zermex), doramectin (Dectomax) or ivermectin (eg Virbamex, Ivomec Classic, Panomec, Noromectin etc) may be used for prevention and treatment of scab although some of these products require a course of two applications.
Always check the datasheet before using any of these products. Be aware that many of these products have long withdrawal periods so contact the surgery to find the product most suitable for your flock.