Every now and again bluetongue vaccines go out of stock. What advice can be given to help limit the incidence of this disease?
Vaccination is, without a doubt, the best precaution to prevent bluetongue. When the vaccination is not available, however, farmers can do the following to mitigate the impact of this disease:
- Avoid unregistered products, vaccinations and home remedies.
- Limit contact between sheep flocks and the midges that spread the bluetongue disease.
- Previously vaccinated animals are less susceptible to the disease than young lambs who require special attention and care.
- Cattle are rarely if at all affected by the virus but are more appealing to midges. If cattle and sheep graze together, midges will be more inclined to go to the cattle. Remember, however, that the virus can still multiply in cattle.
- The midges breed in moist areas, such as swamps. Areas like this should thus be avoided, if possible, especially at night when they are active.
- Where possible, herds or flocks and especially the most valuable animals (like rams) can be kept in a sheltered barn from late afternoon to late morning. Openings in the barn can be covered with shade netting and sprayed with insect repellents.
- Sheep can be sprayed with registered insect repellents over their heads and legs. Repellents that use the ingredient deltamethrin are the best to use for this.
- Since situations differ between districts and farms, the local vet should be consulted for expert advice. The treatment of infected sheep relies on good care, soft food, and where necessary the appropriate antibiotics and painkillers.
Compiled by Dr Faffa Malan, Managing Director of the Ruminant Veterinary Association of South Africa (RuVASA), and Prof Gareth Bath, professor of veterinary medicine at the University of Pretoria.