I WOULD like to try to explain a few facts about the distressing case of Cleo the Cow.

There is a National Eradication Policy in the UK for bovine TB. By law all cattle have to undergo a TB test annually to see if they are infected.

There are two levels of interpretation of the TB test, standard - where no disease has been found in the herd, and severe - where disease has been confirmed in the herd.

If an animal fails the test it is called a reactor and has to be slaughtered in an attempt to eradicate the disease.

Sometimes the animal is borderline and is called an inconclusive reactor (IR) and is allowed to have a second test 60 days later. If the IR passes this test it is clear and lives, if it is inconclusive again or fails the test it is slaughtered.

Presumably Cleo and the other cow were IRs at the first test at standard interpretation and have just been retested after 60 days at standard interpretation.

At this test one cow failed and became a reactor and Cleo passed the test on normal (standard) interpretation.

When the reactor was slaughtered it was found to have TB. At this point the interpretation of the test is immediately changed to severe as disease has been confirmed in the herd.

When this was applied to Cleo’s results it meant that sadly Cleo became an IR for the second time and had to be slaughtered.

The vet carrying out the test should have warned Mr and Mrs Ogden of the risk of Cleo becoming an IR again if the reactor was found to have lesions, and warned them that this would result in her having to be slaughtered. Defra have a clearly set out procedure when it comes to TB testing but unfortunately some of the changes in interpretation of the test when TB lesions are found in reactors are not easily understood by vets or farmers and can cause a lot of distress as in the case of Cleo.

Perhaps it is this that should be acted on?

I would also like to point out that even though the post-mortem on Cleo revealed no gross TB lesions, it takes four to six weeks from initial infection for lesions to become visible, so she may have been in the early stages of infection.

Samples will be sent for culture but even if TB is not grown at culture she may have had TB as it is a notoriously difficult organism to incubate.

Defra-only allow retesting or further tests on an animal that has failed the TB test, is only done in exceptional circumstances otherwise where would they draw the line?

Kate Lloyd