Friday, 28 January 2011

Tuberculosis testing in cattle

This posting has absolutely nothing to do with sheep. Tuberculosis is a notifiable disease, should any farmer suspect he has an animal suffering from TB he is bound by law to notify the necessary authorities - DEFRA. However, in this instance we are talking about cattle, as sheep, suprisingly enough (and horses), are resistant to the disease - amazing to think there is something sheep are less likely to suffer from!

So why am I writing about TB when it has absolutely nothing to do with sheep? Well due to the fact that the majority of the farms in Tarset also run cattle I thought it might be of interest to some to know about the regulations these farmers have to adhere to.

All cattle within the British Isles have to undergo regular tuberculosis testing. The parish of Tarset and Greystead is a 'clean' area and so undergoes their testing every four years - which just so happens to be this year.

So what is TB? Well it is a disease of the respiratory tract spread by a bacteria and passed from animal to animal but will also cross to different species, therefore it is possible for cattle to be infected by badgers, which is a long standing issue which preys on many farmers minds. Badgers carry the TB virus in this country but they are also a protected species. Many years of fighting beaurocracy still seems to be drawing blanks even though a promise of badger culls in the worst infected areas of the country was finally given. Badger numbers have understandably been on the increase since they received their protected species status in 1973.

Cattle can easily pick up the TB bacterium by grazing in areas where badgers frequent, even if you keep your cattle away from areas where the badger actually lives they do tend to wander around quite a lot (badgers that is) and so in a densely badger populated area it would be almost impossible to prevent cattle from having access with badgers. Even when housed for the winter cattle are still not safe from the badger as they will often enter cattle sheds and yards to forage, eating the same food as the cattle have access to.

We know that badgers carry TB and are the greatest threat to contaminating cattle, which are the most susceptible domesticated species to the bacteria, but deer, alpacas, goats even cats and dogs can be infected as can humans. It is the threat to the latter species which causes the disease to be notifiable under British law, the threat to humans.

There are a few strains of TB and in actual fact only half a percent of all people affected in this country have been infected by bovine TB - an interesting statistic! If meat is properly cooked and any milk consumed is pasteurised then the only way anyone could be infected with bovine TB is if infected cattle with full blown TB sneezed or coughed over them and they inhaled the bacteria. Which brings some to question why we still battle on with government enforced cattle testing.

For the time being at least cattle testing is still on the agenda for cattle farmers in this country and as already said this is the time for our parish to have it's cattle tests.

The vets inform the farmers that their test is due and a date is set. Winter time is preferrable for many as their cattle are mainly all housed and so easier to handle. Held together in sheds rather than running all over the farm. Cattle are not always co-operative when it comes to moving them and bringing them into the steading (farm yard), they tend to know something is up and can be wound up to high dough (over excited) before the proceedings get underway. During the winter months and housed they are already 'cornered', makes life a little bit easier!

Within this parish, due to it being a four yearly test it is only necessary to test animals over two years of age (there is an odd minor exception but I don't want to complicate things). Each animal is walked into a cattle crush for ease of working with and operator/livestock safety. A cattle crush is a device designed to hold the animal as stationary as possible and as comfortably as possible, it has an unfortunate name, it most definitely does not crush the animal, although it will often restrain them by the neck in a guillotine type fashion. This may sound inhumane but believe you me it is anything but, years of improvements have produced excellent and safe cattle handling facilities for both man and beast.

Once held secure the vet reads the ear tag number. All cattle in the UK are registered (a legal requirement) and all carry tags in their ears with the required registration data. The tag number of the beast is recorded along with it's age and sex. Access to the neck is necessary as the hair is shaved off two small areas one a distance above the other. The skin at the bare areas is then measured with calipers and the measurements recorded prior to the sites being injected with a laboratory produced TB bacteria. Avian TB as well as bovine TB is injected, the avian is injected in the top area with the bovine further below. Once all the cattle have been dealt with the vet will depart and return in 3 days.

Should an animal be carrying Bovine TB it will react to the injection it was given, the avian injection is given to enable the vet to compare the reactions to the two different forms of TB. When the vet returns to re check the herd he again measures the skin and records the measurements if necessary. It is not unusual for there to be raised areas at the injection sites, however, should the lower area be more pronounced than the higher site (the bovine react more than the avian) then the beast will be classed as being inconclusive and a further test will have to be run in 60 days time.

All in all it is a quite a stressful time for both the farmer and his cattle. The farmer has the concerns that maybe his cattle could be carrying TB, there are not bound to be any signs as it can lie dormant for the whole duration of the animals life, causing no problems to anyone, not even infectious to the other cattle, so a farmer would never know until a test proved positive.

As for the cattle? Well they find themselves being handled twice in one week which can find them getting wound up. Cattle don't always take kindly to seeing strangers, they don't always appreciate being put back through the cattle crush when their memories are still fresh from the incidences of three days ago. It can get them worked up and stressed which in some weather conditions could always lead to them going down with pneumonia, the last thing any farmer would want.

Due to the poor weather conditions at the end of last year many of the cattle tests in this area found themselves postponed until a later date. Even if the snow hadn't caused a problem the ice did. Icy concrete yards are not ideal for moving cattle on, their cloven hooves struggle to purchase in such conditions and it wouldn't have been safe for their welfare or those handling them to work under such conditions. Therefore many of the tests are now taking place which sees the better half helping out many farmers to get their cattle forward for the vets inspection.

Are the tests proving to be clear? Well most are, there has apparently been one inconclusive result which will see the vet return to that farm in March to test that one beast again. Hopefully all will be well and there will be no reaction on the second test. However, should their be a reaction again the farmer will find himself held under strict movement regulations, further tests of the whole herd and more stress. Any animal which is deemed to be a reactor is automatically sent for slaughter, the farmer receives a compensatory payment from the government (which is rarely the value of the animal).

There are many countries which have managed to eradicate bovine TB by testing and culling as our country does, however, it is highly unlikely that the problem will ever be eradicated in the UK as long as the badgers carry the disease. I was told by the vet that it would be highly unlikely TB would kill many cattle, they were more likely to die of other causes or be naturally culled out of the herd by age than end up having full blown TB and die of it. So why test then? Presumably to keep those who work with cattle safe from catching it, as to the normal person on the street who cooks their meat and drinks pasteurised milk bovine TB ought not to be a threat.

3 comments:

Kevthefarmer said...

It seems the ministry in the UK has made the initial test as complicated as possible for some reason- shaving? measuring with calipers? what the @#$!. Stinks of bureaucratic reductionism at its worst or a job creation scheme devised by the vets club. Here in New Zealand the cattle are all lined up in a race and the vet walks along the line bang bang bang the injection in the side of the root of the tail, it takes about two seconds per beast. Three days later he comes back and "manually palpates" (vetspeak for feels) the injection site. again takes about two seconds per beast.
We have a serious issue in NZ with Bovine TB as a lot of the country is bush and is full of possums, feral pigs, and deer, all of which are vectors for TB, although the possums are by far the worst culprits. Our control measures are simple and effective- routine testing of cattle and farmed deer and elimination of the vectors from the margins of pastoral areas. We are winning the battle.
I love this blog- thank you for your time and effort in producing it. Although NZ is blessed with more "wilderness areas" than you are, the beauty of the English farming landscape has no equal in this part of the world.

Tarset Shepherd said...

Hi Kev, pleased you like the blog, thanks for the confidence boost!!
There is no doubt about it that our Government (and not just present day) have spent years 'producing' jobs. We are finding this year that the actual DEFRA vets and employees are doing most of the testing rather than pawning it off onto local veterinary practices, no doubt they feel a need to make their jobs seem worthwhile.
There is no wonder our country is in the mess it finds itself in today.
Very interesting to hear how your country deals with the situation. We seem to have to adhere to stringent welfare rules and a vast amount of red tape to enable us to do anything. Coupled with a greater importance shown for wildlife and environment issues than farming ones, or so it often seems.
Interestingly enough a local vet practice employed a New Zealalnd vet for a while and every farmer in the area wanted to use his services as he was down to earth, matter of fact and just got on with the job. The way he was used to working back home I guess. He was like a breath of fresh air!
Good to hear you're all winning the battle vs TB. A vet told me recently that for us to have had any chance of succeeding a badger cull ought to have been implemented 25 years ago - guess that means we're failing!

John Barness said...

Thank you for the good article.
A friend of mine, who works as a technical specialist in the health care industry told me that virtual data room service are expected to be used for this purpose.