Prepare now to protect stock from Bluetongue
While Bluetongue (BTV) has been an issue in England for two seasons, it has taken longer for BTV-3 to be identified as an issue in Northern Ireland, but the virus has now been picked up meaning that Northern Ireland’s disease-free status is suspended raising questions around livestock movements and the impact on trade.
The Jubilee Vet Centre in Newtownards is the vet practice for all five herds where BTV has been identified.
Vet Andy Mayne comments: “Bluetongue is spread by the Culicoides midge when an infected midge lands on an animal and passes on the virus via biting. The midge is an issue when temperatures are around 10 O C or more and, when you look at this winter, we are reminded it was extremely wet and mild, potentially increasing the risk of midges overwintering.
“Any animal infected around service or in pregnancy runs the risk of not holding to service, aborting, resorbing the embryo, delivering a stillborn calf or a live calf with malformation of the brain, often referred to as a dummy calf,” Andy explains.
In England, the Department for the Environment, Food and Rural Affairs (DEFRA) has reported a number of dummy calves being born; some blind, others with neurological signs such as a head tilt and star gazing, neurological signs, all showing dramatic brain lesions, and typically very little functional brain tissue. These are usually euthanised upon identification.
A number of stillbirths, above average empty rates and some cases of visible lesions around the nose and mouth have also been reported.
“Amongst our clients, the virus has been detected during routine surveillance, usually when we have been TB testing,” Andy adds. “In one herd, which had no clinical signs, two animals that went off to the abattoir were picked up as BTV +ve so DAERA went back and tested and found 40-50 adult cows were virus positive out of a herd of 200.”
Jubilee Vets looks after around 25,000 cows and Andy and colleagues are now advising all clients to consider BTV to be endemic and capable of causing significant and devastating losses.
“We were seeing midges in sheds right up to Christmas time and, with the mild January, the prediction is that they survived, even thrived maybe, and are ready to start the cycle of infection again in 2026,” he says. “Our advice to clients is to vaccinate as soon as possible with the Bultavo® vaccine as it offers insurance against losses and the spend on vaccine is less than the value of losing one animal to the virus.”
Vet Sioned Timothy from Bultavo® vaccine manufacturer, Boehringer Ingelheim has been working with vets and farmers up and down the country since the first BTV outbreak was seen in 2024 and says: “Anyone with breeding cattle due to calve in the first half of 2026 would be well-advised to scrutinise calving data as that will be the first indicator that stock were exposed to the virus last year. Be aware of any abortions, empties, premature births, still births, abnormalities, failure to hold to service and calving intervals that have extended. Examining this information with your vet will help you track back to see if animals were exposed to the virus ahead of pregnancy, in the early stages, or later on.
“Equally, tracking individual cow data in the first 60 days of lactation can be a helpful identifier of exposure; for example, a key indicator of viraemia (infection) is a drop in yield,”
Sioned adds: “We know that an infected cow can have a viraemia for up to eight weeks and a milk drop of 1/litre/cow/day over eight weeks would have a significant impact on overall herd yield. Bultavo® is the only BTV-3 vaccine that prevents clinical signs and viraemia in cattle, prevents clinical signs and reduces viraemia in sheep and can be a valuable tool to help protect stock. It has no known impact on bull or ram fertility, but vaccinating ahead of breeding will ensure that the bull is protected against the potential impact of BTV-3 infection on fertility.”