Cattle on up to six farms have contracted bovine TB (bTB) despite vaccinations to badgers in the area.
However, advocates of the vaccination policy have now questioned its effectiveness.
One tenant of the trust, who supports its vaccination policy “100%” said this week it was not possible to eradicate the deadly disease without a policy to cull sick badgers.
Farmer Jon Kittow told the Western Daily Press how he has been forced to replace his herd of dairy cattle six times in 14 years.
He said: “We are a completely closed herd, we’ve spent tens of thousands on fencing, we have our own transport and there is no contact with other livestock.
“When Defra comes on to the farm after a TB breakdown we tick every box. The only place the TB could have come from is the wildlife.
“What the National Trust has been doing with its vaccination programme is very important – but it is only going to work if you take out the infected wildlife too.
“Increasingly, as a business, we have to plan for failure. Every time my cows go out they are having to dodge a bullet – the bullet that they might get TB.”
The National Trust said it stood by the vaccination trials, which have seen it inject 47 badgers in the first year of trials in 2011; 104 in 2012; 202 in 2013; and 186 in the past nine months. The charity believes it is avoiding vaccinating the same badger twice in any one year by taking a tuft of hair as a marker, though the charity concedes it may be vaccinating the same mammals in consecutive years.
Alex Raeder of the National Trust has been leading the vaccination trial in Devon. He said: “What the trust has been trying to do is something practical about the problem. It would be most unfortunate if the conclusion was that it doesn’t work and culling is better.”
But Mr Raeder agreed with Mr Kittow vaccination alone would not eradicate bTB in cattle.
He said: “We would agree absolutely that if you are really going to get on top of TB you have to address it from as many angles as possible.”
But he stopped short of advocating culling. The trust nationally has remained uncommitted on the issue, although its ruling council voted against a motion to ban any cull on trust land.