A suspected outbreak of foot-and-mouth disease is being investigated in Leicestershire.
The British Department for the Environment, Food and Rural Affairs (Defra) banned the movement of livestock in a five mile radius around a slaughterhouse in Congerstone as a precaution.
Experts are running tests on a pig to confirm whether or not the animal has the disease.
The results will not be known for at least 90 hours, said a Defra spokesman.
A spokeswoman for the National Farmers' Union said: "If Defra confirm that there is a suspected case that is a worrying development.
"This would be the third time we have had a similar scare since the outbreak was seen to have finished.
"We have to await the outcome. Defra will be carrying out their tests and they will check that any risk is minimised."