Bovine Tuberculosis again

It seems to me that little has been done in the past twenty years to effectively control tuberculosis in cattle. The Independent Scientific Group decided that one third of new cases occur as cattle to cattle spread, one third as a result of infected animal movements onto farms and the rest are the result of the activities of wildlife, which means badgers to you and me. It might well be that in the past when tuberculin tests came around every four years and most reactors were older cows that could have been infected for some time and there were opportunities for lateral spread of the disease. Nasal swabs have now been taken from several thousand animals that were subsequently confirmed as reactors but so far none of the samples have revealed the presence of any pathogenic bacteria. Some outbreaks have resulted from stock movements onto farms, but extensive pre movement testing has been going on for some time now. It is not very likely that significant numbers of animals could get infected in this way.

Flawed Control Policy

Since the long awaited report form the Independent Scientific Group was published in 2007 movement restrictions have been put on all herds with overdue tests and the gamma interferon blood test has been used on problem herds and those with Inconclusive Reactors. In spite of this last year there was an increase of 24% in the number of breakdown herds in England. Of more concern has been the high numbers of reactors that have been found on some farms. There are not many people who think that our Tuberculosis Control Policy is working. So what are the options now?

Proposed Changes for England

In England it has been announced that from next summer there will be a trial in six areas of the country to determine if there is any benefit to be gained by vaccinating badgers with the BCG Vaccine by injection. The vaccine will be used over a period of at least five years and the impact of the trial on the number of herd breakdowns will be carefully accessed. There are still indications that an oral bait vaccine will be licensed eventually for badgers, but this is still five years away and it will not be used for this trial. This sounds like another one of DEFRA’s long term studies. It has been shown in the past that there are difficulties trapping badgers as only a small percentage of the animal are attracted by the traps so the effects might well be limited.

Proposed Changes for Wales

The Welsh Minister for Rural Affairs Elin Jones is not afraid of confronting controversy. Faced with the dilemma that in 2008 over twelve thousand cattle from Wales were slaughtered with Tuberculosis, this is a 52% increase on the previous year, she has come to realize that further increases will not be sustainable. She has been able to argue her case from both financial, animal welfare and the huge impact it is having on her farming community. So far Cattle Health Check Wales has started to test all of the cattle herds in Wales in a fifteen month period and has identified 23 new infected herds and they have also reduced the number of overdue tests by over 80% to gain a clearer picture of where the disease is active in the country. In Wales the skin test is interpreted more stringently and Inconclusive Reactors are taken at an early stage before they become infectious. Of more importance is the plan to work in Intensive Pilot Areas in Pembrokshire to have a controlled cull of badgers. At the moment the preferred method will be cage trapping and shooting over a period of four years. In Wales they have not ruled out the use of vaccine on badgers in some areas, but they do point out that the more effective way will be the oral vaccine and that it is a long time to wait for that to become available in 2014 if indeed it does come into use at that time. The Welsh Minister is under no illusions that these polices will cause a certain amount of controversy, her over riding aim is to see Welsh livestock and Welsh wildlife co-existing in a healthy environment which is clearly not the case at the moment.

Possible Control Measures in the South West

Meanwhile I have heard about a private initiative in Devon and Cornwall to survey and access the health status of badger setts. In selected areas where there are at least six farms on 60 day testing an assessor will be employed to go onto the farms and map out the badger setts and determine by the activity at the setts whether they are likely to contain healthy or diseased animals. Once all of the farms have been surveyed and the status of the setts has been mapped a meeting is arranged with all of the farmers and their Veterinary Surgeons. So far they have found that given a typical area of ten farms with up to 300 badger setts 10% would show evidence of the presence of unhealthy badgers. It is hoped that by next autumn consent will be available from DEFRA for trained people to deal with the unhealthy setts. There is no specific indication as to how this would be done, the assumption is that carbon monoxide gas would be used. The group behind this has costed out the programme and will charge £250 from each cattle farmer involved. They realize that some of the unhealthy setts will be on farms without cattle and that these landowners will not be expected to pay. It will be interesting to see how this private scheme works out. The biggest problem will be that there needs to be a change in legislation if there is to be a cull of a protected species. The plan is to repeat the exercise each winter because if you can keep the local badger population healthy and improvement in cattle health will follow.

Lame Cows at Pasture

If this spell of dry weather continues more and more dairy cows will be out at pasture during the day. The ground is hard at the moment and already we have had problems with lame cows with bruised soles. Some cows cannot cope outside at first after spending the past six months confined to your buildings where they can sometimes hide their foot problems by not moving around too much. Keep a close eye on the cows when they first go out. Have a good look at the feet of the slower ones and those that are showing any signs of lameness. It is better to keep these animals together in the buildings until you have had a chance to get their feet trimmed. If your yards have been wet and the feet are soft get them to walk through a formalin footbath to harden the feet before they have to walk too far

Nitrate Poisoning

It is dry at the moment and some lambs will be attracted to nitrate fertilizer that has been spread on the fields but has not had a chance to work into the ground. This chemical is converted to nitrite in the stomach to block the uptake of oxygen from the bloodstream. Take care as there is no reliably treatment should this occur.

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