A farmer whose cattle have tested positive for bovine TB has said she will not allow officials to kill them.
The farm has 100 beef cattle
Margaret Booton, of Lower Snead Farm near Worcester, said she would not cooperate with Defra.
She said a skin test was not accurate enough as two years ago four pregnant cows which tested positive and were killed turned out to be healthy.
Defra said the test was up to 95% accurate in finding the infection, and guidelines said animals must be killed.
Eight of 100 beef cattle on the farm have tested positive for TB.
Samantha Qureshi owns between five and six of the animals, some of which have tested positive.
She has asked the courts to inform her of any application that is made to remove the cows for slaughter.
'Legal steps taken'
"We have to be sure that these animals have got TB before we would even consider letting them go and I'm certainly not convinced," she said.
Mrs Booton is writing to Defra's chief veterinary officer calling on policies to be changed.
A spokesman for Defra said no diagnostic test, including the tuberculin test, was 100% accurate.
He said: "When used as a routine screening test, it is designed to maximise identification of uninfected animals (at an accuracy of 99.9%) whilst retaining good identification of infected animals (at an accuracy 77% to 95%)."
In a statement the department's State Veterinary Service in Worcester said it was unable to discuss individual cases but if animals were found to have a reaction to the skin test they need to be removed from a farm.
"Papers regarding this removal are sent out and a valuation of the stock is arranged," the statement read.
"There are legal steps that can be taken to ensure the removal of animals."