A flock of sheep grazing at Maurice and Ann Gerry's Broadwell Farm were found to be infected with the virus on Saturday. All 170 animals were slaughtered on Tuesday.
The sheep belonged to Alan Viggers from Tavistock.
He said: 'I've got around 1,200 other sheep and 110 cattle. They are being checked daily by the MAFF vets and have so far shown no signs of any infection. But they will all be slaughtered later this week as a precaution, which I totally support — we've got to get in front of this bloody disease.'
Mr Viggers said ewes show no signs of the disease, but the newborn lambs were hit hard and were very distressed.
'Those lambs, they looked terrible, no one would want to see an animal in that state, they looked really terrible,' he said
Mr Viggers said he thought he was in full control on the Saturday when the infection was found and was so busy on Sunday that he had little time for it to sink home.
'But on Monday I broke down. It really, really hit me,' he said. 'Now I've got to sort this out, and I will.'
The outbreak has created chaos and fear on the Gulworthy farm of Mr and Mrs Gerry.
They fear for their own small number of animals and how they are to manage in the coming months. They are also bewildered, not knowing what is happening.
'The vets are supposed to come every two days, but much more than that I don't know,' said Mrs Gerry.
The corpses of the 170 sheep are lying in a field at the top of the farm that is completely off-limits, awaiting disposal.
'The trouble is the food for our bullocks is in the top field, in the restricted area, and we can't get to that. We haven't got enough grass and may have to buy more in a couple of days,' she said.
Mrs Gerry said the rest of the farm will not be able to be used for the next six months, removing any income they might have had.
'It goes against the grain, but the best thing might be for them to be killed, but we have no say in the matter — if we ask, we won't be able to get any compensation,' she said. 'The emotional upheaval is unbelievable, the Ministry of Agriculture is in a complete mess, nobody really knows the answers.'
Tavistock businessman Simon Allen lives with his family in a barn conversion on the farm. He has imposed a voluntary quarantine, although, according to MAFF, both they and Mr and Mrs Gerry are free to come and go so long as they disinfect themselves.
'It's an absolute nightmare,' he said. 'We don't know if we should leave the farm or not. The Form B restriction means we have to disinfect, but we could be dragging this disease all around the countryside and the sheep killed on Tuesday are going to stay on the farm for up to seven days rotting and stinking. They will be taken by badgers and foxes, spreading the disease.'