Tagging Sheep

From time to time delegates from the EEC come to inspect abattoirs and farms to determine if we are working to the current regulations. It would appear that on a recent visit there was criticism of the ear tagging system and record keeping on sheep farms. I have noticed in the past six months at both Shrewsbury and Bishops Castle markets that there have been very few animals that are not correctly identified. I do not think that there is a significant problem locally. At the moment we are the only country in Europe that does not double tag sheep, the rest of the EEC is moving towards a system of electronic tagging for sheep and goats. So far we have resisted these new measures, but it is going to be difficult to argue our case if the British rules are regularly broken.

Brucellosis Monitoring

The Chief Veterinary Officer has announced that as from the 9^th April there will be no more routine monitoring of cattle for Brucellosis in the UK from blood samples. In the future we will rely on samples taken from imported cattle, from bulk milk tank samples and from investigating animals that have aborted. It should be remembered that this is an important zoonotic disease affecting both farmers and vets.There has been no discussion of this in the Veterinary Press. Brucellosis does occur from time to time, the last outbreak was in Dorset in 2004. Most recent cases have been related to imported cattle as was seen in North Wales in 2003. In the past the serum samples taken from cattle for Brucellosis eradication have been used to monitor other diseases. This is how warble fly infestation was tracked to isolated areas of the country and increases were observed when it was not adequately controlled in imported dairy cattle. Warble fly has now been brought under control and it is Blue Tongue that is the new danger. It will not be so easy to investigate the spread of diseases in cattle when the blood sampling comes to an end.

Reporting Abortions

From April it will be even more important to report to us all cattle abortions. On dairy farms it is usually only after a second abortion that samples will be taken. All abortions are investigated on farms that are not selling milk for human consumption. We often take this as an opportunity to look for the other common causes of a failed pregnancy or at least to confirm that that there is not a disease process involved.

Controlling Tuberculosis

Thirty years ago Tuberculosis was thought of as a conquered disease. In cattle the numbers of infected herds were dwindling year on year most herds were on four yearly testing with only the cows and bulls having the injections except for a handful of locations in the south west of the country. Even when it was first realised that badgers were involved in the disease process control methods did seem to be working until they were suddenly brought to a halt when badgers became a protected species. It is interesting to note that Australia and New Zealand had reached a similar point in the mid seventies and that they at least have had better success at controlling the infection.

Australia

Australia was declared free of Bovine Tuberculosis in 1997 after a seventy five year battle with the disease. Since then there have been only a small number of herd breakdowns and none since 2002. In the nineteen seventies it was realised that as well as the cows Asian water Buffalo and feral pigs also had the disease. In that country the role of wildlife reservoirs of the disease were understood. They were able to cull the infected water buffalo and found that the pigs were an end host to the disease, they caught the infection when cattle were heavily infected, but were unable to excrete the bacillus and did not pass the infection back to cattle.

Regional Controls

In Australia movement controls were much stricter than they are here. After a herd breakdown no cattle movement could occur for at least two years after all of the cattle tested clear. There were strict movement controls within regions so that animals were not able to move from a high disease region to clean areas. For many years this severely restricted the traditional trading patterns of livestock within the country. It was effective in the end even though they use just a single tuberculin injection in Australia which is not thought to be as effective as the double injection we have here.

New Zealand

New Zealand has not found it easy to eradicate tuberculosis because it was prevalent throughout the country and it was realised in the late sixties that Brushtail Possums also had the disease. In New Zealand control programs were linked to the tuberculosis history of the farm, the accessed risk from infected wildlife and the disease status of the region. Things were working well in the late 1970’s when the number of cattle testing positive was low and all expectations were that the disease would soon be eradicated from both cattle and farmed deer. Things did not go quite as planned as the number of herd breakdowns increased over the following fifteen years. There was then a massive effort to bring things back under control and currently 67% of the money spent on tuberculosis is used to identify and cull the wildlife vectors. They have now reached the situation where there are some herd breakdowns, but the underlying trend is to uncover the spread of infection in wildlife which is proving to be more and more costly to control.

United Kingdom

So what dose this mean for cattle in the United Kingdom? In the mid seventies we did start to investigate our wild life vector with some success, but that soon drew to a halt. We too have infected regions, but there is no policy to treat areas where there is a high prevalence of the disease in a different way than the rest of the country. We know more about our wild life vector, we know that it is very susceptible to the infection from as little as ten organisms, which is a very small amount. We are well aware that because it lives underground the infection will readily spread. There is talk about vaccinating wild life and reducing the spread of infection, it is difficult so to see how this is going to work.

Spread of Infection

In the meantime we are seeing an increase in the disease in wild deer and nothing is done to limit the numbers of wild boar that are a problem in many areas of the country. Bovine Tuberculosis is sometimes seen in cats and a single dog in the West Country was known to have been infected by the organism. I am not sure exactly what has to happen before we start to realise that Tuberculosis is a devastating disease that we must get under control. The longer we leave it the more difficult and the more costly it will become.

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