Vets working on vaccine for cow infection which as devastated Jeremy Clarkson

Vets have told how cattle vaccine trials on eradicating bovine TB have shown "really promising" results. TV presenter Jeremy Clarkson has catapulted the issue into the spotlight when his Diddly Squat Farm, in the Cotswolds, was hit with a case of the disease earlier this month.

The vaccination of cows and badgers is significant because farmers and scientists have long been at loggerheads over the culling of the latter as a way to control TB.

Sarah Tomlinson, the lead veterinary science expert at the Agriculture and Horticulture Development Board, said: "TB is actually on decline massively in England and Wales because governments have had a control strategy for quite a number of years. It's not perfect and there's always evolving science and evidence that we can change policy to keep driving those disease levels down but in England we are at the lowest level of TB we've had for 20 years and so that's a positive story.

Ms Tomlinson told how cattle vaccination for TB looks "really promising". The animal expert added: "The problem has always been that if we vaccinate cattle, about 80% of them would test false positive on our skin test. So what we needed to develop, which is there now and is at field trial stages, is a test to be able to pick out the infected ones so we can still remove them, but leave the vaccinated ones behind. So that is a really big thing that hopefully will make quite a big difference."

Cattle which fail a TB test, or animals that have inconclusive results for two consecutive tests, are classed as "reactors", and must be isolated and slaughtered.

Bovine TB is recognised as a problem which devastates farm businesses and is mainly spread through close contact when cattle breathe in droplets of mucus containing Mycobacterium bovis bacteria exhaled from an infectious animal.

Badgers can carry the disease and culling has long been a part of the Government response to the crisis, despite criticism from wildlife and animal welfare campaigners, such as Queen guitarist Sir Brian May.

The Government said in June it will not be extending the badger cull and retains its commitment to end the practice before the next election.

Dr Paul Horwood, IVC Evidensia Group's vet advisor for farm animals, said: "TB's been in this country forever really and we've been trying to eradicate it for a long time.

"What we've been doing until, probably the last 10 years or so, is just testing and culling, testing and culling, testing culling. That's sort of kept a lid on it but we've never been able to eradicate it out of the country completely.

"A few things are now changing. There's some trials coming through, which might help. We've got some interesting looks at vaccination, which will be quite interesting. Cattle [TB vaccines] are still at the trial phase. Badgers have a role in it. They do carry bovine TB. They do interact with cattle. And so we can't just focus on the cow to eradicate it. We're looking at a number of small-scale trials which hopefully will be ramped up looking at vaccinating the badges so that we can eradicate TB in badgers and in cattle, which would be obviously where we want to be."

A three-year trial in Cornwall last month started with 70 farms and involved farmers trapping, testing and vaccinating badgers, with training provided by scientists.

An earlier pilot study of the approach showed TB rates in badgers fell from 16% to zero in four years.

TB can devastate cattle herds and more than 20,000 infected cattle were slaughtered in the last year in England. The badger cull started in 2013 and has killed about 250,000 badgers but has been highly controversial. Badger culling is due to end in 2029.

Mandatory bovine TB testing, paid for by the Government, is required every six months in high-risk areas.

But it can be up to every four years in lower-risk places.

Will Simkin, who runs Essington Farm, said: "Farm shops are often reliant on small scale, local beef farmers, who breed specific cattle for the farm shop sector. These cattle are of a unique specification, much different than beef produced for the supermarket industry and can be from rare breed cattle.

"If bovine TB gets into these unique herds, the impact of culling the infected cattle can be devastating as proportionately a large percentage of cattle that fit the farm shop specification can be wiped out."

The farmer, who is part of the Farm Retail Association, added: "This then leads to farm shops having to look further afield for suitable cattle that may not be there, reducing marketability, increasing cost and increasing food miles.

"Ultimately it is the consumer that loses out through reduced availability of quality, rare breed cattle sold through their local farm shop."