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Bovine Tuberculosis (TB) Tuberculosis
(TB) in both humans and animals is caused by a bacteria. Bovine TB - Blogspot - Click here! TB Testing The Government has ordered TB testing of cattle as a control measure to prevent the spread of TB and the following is a simplified guide to why and what happens in TB Testing. As every area, herd and farm is different if there is anything you are unsure of please don't be afraid to ask your vet. The
Government's policy for controlling TB is their programme of testing
cattle and slaughtering any that react 'positively' to the test. Testing
cattle
Cattle
are tested every 1, 2, 3 or 4 years, depending on how much TB has been
found different areas. Strengthening
controls TB
in cattle has been increasing in recent years so controls on cattle have
been ordered to try to bring TB under control. Changing
the dates of tests The
dates of some herd tests are being done earlier than was previously
planned to make sure that they are done more frequently even every year
in some areas. This should help them to pick up the spread of disease
and take action to stop any further spread. They
are also reviewing the testing frequencies for every area to improve
control. The
Changes Proposed
changes include:
Do
you want to buy cattle?
Farmers
can request a copy of the Tuberculin test report and Certificate of
clinical inspection (Form TB52).This gives information about the most
recent tests on the herd and the results. The farmer can pass this on to
the buyer who can use the information when deciding to buy the animals. Other
measures All
cattle sent for slaughter are inspected by the Meat Hygiene Service both
before and after slaughter to check for a variety of diseases and
occasionally TB is identified. If this happens, the herd from which the
cattle came from will be put under movement restrictions and tested for
TB. What
happens? All
cattle herds, except beef fattening units, are routinely tested for TB.
The frequency of the test depends on how many cases of TB there have
been in the area. The test will usually be carried out every four years,
although in parts of the south west, south Wales and the Midlands it
will be every 3 years, 2 years or every year. All
eligible cattle in a herd are tested for TB using the skin test (single
comparative intradermal tuberculin test), a small injection into the
skin on the neck. Three days later (72 hours), the vet returns to the
farm, to examine the cattle and look for any 'reactors'. If there are
any, they are identified by a small swelling or lump around the
injection site, measuring about 4mm or more in diameter. Passing
the test If
none of the cattle react to the skin test and no lump or swelling
appears, they've passed the test and no further action is necessary,
until the next routine TB test (in one, two, three or four years time). Failing
the test If
any animals react to the skin test and a lump or swelling appears, the
swelling is measured with callipers and if it is 4mm or more in
diameter, they fail the test. Cattle that react to the skin test are
termed "reactors" and are removed from the farm and
slaughtered. The
Government give the farmer 100% compensation for any cattle slaughtered.
No cattle are allowed in or out of the herd unless sent direct to a
slaughterhouse, under a licence and conditions specified by the
Agriculture Department, to prevent the possibility of TB spreading. What
happens then
(NB.
In areas where TB seems to be on the increase, the vets have great
experience in testing for
TB. So if you are unsure of what is being done or how
the test is being read, please ask them. It is
important to understand that if the measurements of the skin's reaction,
(a lump or swelling) in the first test is up to 4mm in diameter it
would be judged a
'reactor'. This is referred to as the 'standard' test. If on
laboratory examination after the slaughter of cattle showing such a
reaction, disease is
found, when the herd is re-tested, the measurement can
be reduced to 2mm and this is referred to as the 'severe' test. This
may seem rather unfair to the farmer who notices the reaction is far
smaller than the one in
the cow(s) he has lost and yet it is to be marked as a
'reactor' and sent for slaughter. However, the risk that his slaughtered
animal(s) now known to
have been infected, may have passed on the disease
is too great). It
can happen that animals from a herd that contained a 'reactor' in which
disease was found after slaughter, can be deemed 'reactors' on re-test
and yet are found not to have had the disease on post mortem
examination. This is sad but at present, unavoidable. Rresearch is
ongoing into the possibility of a blood test, which will indicate
whether or not the animals are infected. If this becomes available it
will make a great difference as restrictions and re-tests will not be
necessary. If however, the herd is
free of TB. Movement restrictions are lifted. To make sure the herd
remains free from TB, another test is carried out Inconclusive
reactors Some cattle may react
only slightly to the skin test, and the vet's not certain whether they
are reactors or not. These are known as 'inconclusive reactors' or 'IRs'
and they are isolated from the rest of the herd and retested after 42
days (1st retest). If they pass the test, and there are no other
reactors in the herd, they can return to the herd . If they pass the test,
but there are other reactors in the herd and TB has already been
confirmed, the IRs can return to the herd, but restrictions on the herd
will already be in place If they fail the test,
and there are no other reactors in the herd, a new herd incident
(breakdown) starts. IRs that remain
inconclusive after this first retest are tested once again after another
42 days (2nd retest). JB. For information about the current research into providing a vaccine to protect cattle from TB click here - For more information about controlling TB in your herd - click here! ‘Dealing with TB in your herd’): If you have any more questions do call your vet or local Animal Health Office or even 'me' - I'll try to help! 01361-850282 Best wishes - Jane Barribal -Farmtalking.org
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