Bluetongue virus: The outbreak of the bluetongue virus in Devon, Somerset, Cornwall and the surrounding areas in the southwest of England is hitting farms in the region hard.

The severity of disease is much more serious than in 2025, when the greatest issues were seen in reproductive performance and foetal deformities.

The latest outbreak is characterised by clinical symptoms of disease with animals quickly succumbing to the disease.

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Reports indicate that the number of cases being officially reported is much lower than in reality due to the fact that the Department for Environment, Food and Rural Affairs is covering the cost of diagnostic testing for up to three affected animals and more farms are not testing.

Vets report widespread problems on affected farms, with sheep displaying characteristic symptoms of lesions/ulcers on the mouth, nose, tongue and feet, swollen lips, tongues, head and feet (inflammation at the coronary band), discharge from the nose and eyes and profuse drooling from the mouth. Sheep that succumb to the virus quickly enter a depressed state, with a reluctance to move or eat.

Fever and breathing problems are also seen, with cases of mortality being reported in sheep. There is no way of telling how the virus will spread with vets in the area warning of ideal environmental conditions for the virus to spread and replicate in the midge population. The Department of Agriculture, vets and farm organisations are advising farmers in Ireland to avail of vaccination as we head into the high risk vector season spanning from August to October.

Vaccination will not prevent the virus from spreading but it will reduce what is known as viraemia, or spread of the virus, and clinical symptoms. There are three vaccines on the market for bluetongue virus serotype-3; Bluevac-3, Bultavo-3 and Syvazul BTV 3.

The onset of immunity following vaccination in sheep is three weeks in Bluevac-3 and Bultavo-3 and four weeks in Syvazul BTV 3. Bluevac-3’s primary vaccination course requires two doses administered three weeks apart with the other two products requiring a single primary vaccine in sheep. The vaccine must be ordered through your vet. There is an allowance from the Department that one vaccine pack can be prescribed and dispensed to more than one herd or flock subject to veterinary oversight and maintenance of strict biosecurity, where numbers requiring vaccination are small.

Fertiliser application: There has been significant rainfall across much of the country over the last week, but there are still some areas worst affected by drought that have only received small volumes. It is important to try and get the grazing season back on track as soon as possible. The earlier fertiliser is applied in August, the greater the response will be.

There will be a natural boost in grass growth from rainfall on soils with a high temperature but nitrogen will be required to build grass reserves heading into the autumn. The application rate will depend on grass availability, demand and whether or not another round of fertiliser will be applied on given areas. Highly stocked farms will typically require in the region of 25 to 30 units N/ac (30.75kg to 37kg N/ha) while for lowly stocked farms 10 to 15 units (12kg to 18.45kg/ha) may suffice. Measures to conserve grass supplies will continue to be needed on farms badly affected until grass reserves recover.