Breeding company Cogent introduced the Big Brother-like measures last week in the hope it would make the bulls exempt from slaughter should exclusion zones be extended.

Fourteen miles is too close for comfort. This way we are stopping any windborne infection or transfer by birds

Tim Heywood Cogent MD

The Holstein bulls, which are extremely valuable, are used to produce semen for breeding programmes in the UK, and for export to the US, Australia and Europe.

The Grosvenor estate is about 14 miles away from an infected foot-and-mouth area.

Cogent managing director Tim Heywood told BBC News Online: "Fourteen miles is too close for comfort. This way we are stopping any windborne infection or transfer by birds."

He said the vet and the studman, who have been joined by the studman's girlfriend, are in "excellent heart and spirit".

They are getting regular deliveries of food, fresh clothing and a few home comforts, including some beer.

The only exterior air allowed to enter the specially modified barn is being pumped in through Ministry of Agriculture-approved filters which are constantly monitored.

Splendid isolation: The bulls in their pens

Mr Heywood said the self-imposed exile may have to last for several weeks, but those people within the air-tight barn could be replaced by a new team.

He believes the government had managed the foot-and-mouth crisis well initially but now regards resources as being over-stretched.

He said: "The vets are like a peace-time army coping with what is now a wartime situation.

"It has turned into a major logistical exercise and the introduction of British troops can go some way to helping the situation."