Farmers across the UK are waiting to see whether the discovery of foot-and-mouth disease at a farm in Surrey is an isolated case.
Every cow has its own passport
Sussex farmer Jane Howard says it is crucial information about infected animals and where they might have moved around the country prior to their diagnosis is given as soon as possible.
She said the authorities were in far a better position to track the movements of the animals involved than at the time of the 2001 outbreak.
Mrs Howard said as each cow now had its own passport - a measure brought in as a result of the BSE crisis - it should be easy to trace where each animal has been.
Revealing how much the animals have moved around the UK before their diagnosis would put farmers' minds at rest, she said.
Mrs Howard, who has cows, sheep and pigs at Cooper's Farm in Wadhurst, said the industry was now "hugely regulated".
If a cow is moved from a farm, the British Cattle Movement Service must be told within three days.
She said: "As far as farmers are concerned we are all sitting here hoping.
"If the animals haven't moved around too much there's a greater chance that this can be contained than if they had been bought at market last week.
"I can't understand why they can't tell us that now."
The Cranleigh Agricultural Show was due to take place in Surrey on Sunday.
Mrs Howard said: "If this had been found 24 hours later there would have been 400-500 cows from all over the country there. In a way it is lucky.
Police cordons have been set up in the area surrounding the outbreak
"Everyone feels absolutely sick."
Sally Robinson, from Boyd's Farm, Wiltshire told BBC News 24 she was "absolutely devastated, numb, in complete shock, just can't believe it can happen again".
She said when the disease broke in 2001, her farm was closed down and she lost her job.
"We all lived on a day to day basis on our nerves," she added.
Mrs Robinson said she was satisfied with the government's response so far. "I am happier that the movements have stopped quicker than they did last time.
"Last time it was detected on 19 February and markets were still going on 23 February, so there was six days of movement.
"But now it's been declared straight away."