A ban on livestock movements brought in following an outbreak of foot-and-mouth in Surrey has been eased.
Thornton-le-Dale show in Yorkshire went ahead without livestock
Following the midnight restriction changes, farmers outside the county's surveillance zone can take livestock to slaughter and dispose of dead animals.
Meanwhile, culling has been ordered on a third farm, next to the second farm already affected, on suspicion that the disease could be developing there.
A European Union export ban on British meat and livestock remains in place.
HOW FOOT-AND-MOUTH SPREADS
Direct contact, from animal to animal
Fluid from an infected animal's blister; saliva, milk or dung also pass on the disease
Animals eating infected feed
Virus can be spread by people or vehicles, if not disinfected
Airborne spread of disease also possible
Animals can begin spreading virus before visible signs of disease emerge
And an investigation into the origin of the outbreak is continuing.
The first cases of foot-and-mouth were found in cattle at Woolford Farm, near Guildford, on Friday and a second outbreak was confirmed at a farm on Monday. Cattle in both cases have been culled.
Chief veterinary officer Debby Reynolds told a news conference on Wednesday she had also ordered livestock on a third farm to be killed, on suspicion the disease may have spread further.
"I cannot rule out that disease is developing on the premises," she said.
On the rules on movements, Ms Reynolds said they would be allowed only under strict licensing conditions, including biosecurity measures on farms, in transport and in abattoirs.
"I continue to urge all farmers and all others involved to take the highest level of biosecurity measures and to follow the conditions of the licences in every respect," she said.
Other movements of livestock, such as sending animals to market, are still banned.
Some restrictions had already been lifted in Scotland and Wales.
Kevin Pearce, director of food and farming at the National Farmers' Union, welcomed the relaxation of rules and said abattoirs would be up and running as early as Thursday morning.
Chairman of the English Beef and Lamb Executive, John Cross, said the lifting of the ban would be "a great relief" to farmers but it would take time to return to "business as usual".
Paul Langthorne, a buffalo farmer in North Yorkshire, told BBC Radio Five Live the restrictions had been hitting his business.
"If the ban had stayed on, we'd just have used up all the meat in the fridge and then we'd have had to stop trading," he said.
Health inspectors are looking into the possibility that the disease was originally transferred by employees at vaccine manufacturer Merial, based just a few miles from the farms.
The Health and Safety Executive has said there is a "strong probability" the outbreak began at the Pirbright research site, home to both Merial and the state-run Institute for Animal Health.
Both facilities had been using the strain of the virus, but the HSE did not specify which of the two was to blame.
It is understood, however, that investigations have discovered a link between problems with drainage and the possible actions, accidental or deliberate, of Merial employees who may use nearby allotments.
Soil samples from the Merial site are being tested and the results are due on Thursday.
Merial said it had conducted "intensive internal investigations" and had "complete confidence" in its processes and procedures.
It confirmed one of its employees had accompanied investigators to an allotment but said there was "no evidence linking this member of staff to the outbreak".
At a meeting in Brussels, EU veterinary and food safety experts decided emergency measures banning all British exports of meat, milk products and live animals would remain in place until 25 August.
The committee will meet again on 23 August.
Prime Minister Gordon Brown chaired another meeting of the Cobra emergency committee on Wednesday evening to discuss the outbreak.
Following criticism from some farmers and opposition parties, all footpaths within the 3km (1.8 mile) protection zone around the affected farms in Surrey have been closed.
A 10km (6.2 miles) surveillance zone is also in place.