By Dr Faffa Malan
When Plan A – the vaccine – is not available, there are measures farmers can take to mitigate the impact of the disease.
Vaccination is, without doubt, the best precautionary measure to prevent bluetongue. Still, when the vaccine is unavailable, the most crucial advice is to reduce sheep’s exposure to the midges. Also, avoid unregistered “remedies,” “vaccines,” and folk remedies.
Previously vaccinated animals are less susceptible than young lambs – they require special attention and care. Cattle are not usually affected by the virus; when they are, the effects are minimal, but cattle are more attractive to midges than sheep. If cattle and sheep graze together, midges prefer the cattle, but the virus can multiply in cattle.
Midges breed in damp areas, such as marshes, and such places should be avoided, especially at night when the midges are active. If possible, the flock and especially the most valuable animals, such as rams, should be kept in a sheltered shed from late afternoon until late morning.
Openings can be covered with shade netting and sprayed with insect repellents. Sheep can be sprayed with registered insecticides over the head and legs. The best ingredient for this is products containing deltamethrin.
Consult your local veterinarian for expert advice because the situation can differ between districts and farms. Treatment of affected sheep relies on good care, soft food and, if necessary, appropriate antibiotics and pain relievers.
Compiled by Dr Faffa Malan, manager of the Ruminant Veterinary Association of South Africa (Ruvasa).
