Diagnosing Sheep Abortions

Enzootic Abortion continues to be the most frequently diagnosed cause of abortion in sheep. Chlamydophilia abortus grows in the placenta and starves the developing foetus of essential nutrients and oxygen. It is usually diagnosed by taking a smear from the placenta and examining it under the microscope. Until now tests have always been carried out as well as the smear to make sure that there has not been any other infections that have caused or contributed to the pregnancy loss. It has now been decided at the Veterinary Laboratories Agency if the smear test is positive for enzootic abortion no further teat will be carried out. Whilst I can appreciate the laboratory is keen not to waste resources, by doing un necessary tests, from time to time we do come across mixed infections. Enzootic Abortion will weaken the foetus and other organisms may become established that lead to the loss of the pregnancy. I feel that this is false economy if you do not look for things they will never be found, it is better to get the whole picture and not assume that the first positive result is the full cause of the problem.

Brucellosis in Belgium

Last December there was an outbreak of Brucellosis in Belgium. Many of the cattle that come to this country from Europe will travel through Belgium, fortunately there have been no positive cases here so far, but it isn’t very far away. You will be aware that there is now no routine testing of cattle in the UK for this disease. Milking cows are monitored from a bulk tank sample each month, but most cows and bulls are never tested so there is a danger that it can spread un noticed. It is important still to report cattle that abort, especially if they are suckler cows, so that we can come and make sure that Brucellosis is not involved.

Poisoned Hens

If like me you keep a few hens or ducks you might well be troubled by rats. In the past it has been mainly warfarin based products that have been used to control rats. Fortunately birds are fairly resistant to warfarin and they can take in a moderate amount with no ill effects. Chickens are however very sensitive to the newer rat baits containing bromadiolone and difenacourm as even the smallest amounts will kill most birds. Hens will find bait sometimes if it has been put out of reach in a drain pipe or rodents have carried small quantities out into the open. Take care if you are using the newer rat poisons as they are very toxic to birds and there is no effective antidote.

Acute Pneumonia

Histophilus somni is a gram negative bacterium similar to pasturella that will cause acute pneumonia in mainly intensively reared cattle. Often there are few signs that affected animals have the disease until they are found dead. This is a bacterial infection that does not respond well to either antibiotics or anti inflammatory drugs. It is an acute infection that will cause a build up of fluid and lead to consolidation in the lungs. Fortunately it will usually only affect individuals unless there are other pathogens present to further damage the lungs. Calves are particularly vulnerable to Histophilus after weaning and for the first sixty days when they go onto a new ration. Vaccines have been used in other countries to try and control this disease. They have been shown to give a good response in the blood, but they do not always stop the infection. In some countries antibiotics are fed for the first two months when cattle have a change of diet. It is not thought that this approach is cost effective here because of the quantities involved and the problems of inducing drug resistance. If you rear a lot of calves it is worth while to have any unexpected deaths investigated. If you are aware that you have this infection on your farm it might be possible to give the affected group more space and  plan any diet changes so that they do not clash with handling for castrations and disbudding.

Badger Control

Despite the previously announced intension to publish a balanced and comprehensive programme for eradicating bovine TB early in 2011 it now appears that the new Government’s decision on whether to allow a limited badger cull as part of this process has been delayed. At a conference on February 16^th it was reported that questions brought up from the consultation process and the difficulties in answering them had contributed to the delay in announcing the decision. It is thought that whatever decision is arrived at it will be challenged in the courts, so it might be that DEFRA are making sure that they can win the argument when this happens. This time last year the conservatives were pointing out that the current control policies were not working and that a new approach was needed. It seems a long time now since the General Election and it is frustrating that even thought there has been a change of government there has been no change of policy.

What are we waiting for?

It is difficult to see what further evidence is needed as the trials and reports were all completed long ago. We are not the only country that has a problem with Tuberculosis in farmed animals. We are, as far as I can determine, the only country who is trying to tackle TB without any wildlife controls. Just a few weeks ago DEFRA was determined to sell the English forests as they do not seem to have the recourses to manage them properly. They had a sudden change of mind in the early stages of the public consultation process and now there has been a complete policy change.

Costly Delay

I do not think that it will be possible now to eradicate tuberculosis from farmed animals in England and Wales as it is so firmly established in badgers, deer and other wildlife. The best we can hope for is rigorous control policy that will reduce the impact of the disease on farmed livestock. I notice on the BBC News website that they understand an announcement about badger culling will be delayed until May. If that is the case it is most unlikely that anything will happen this year. 

Disappearing Drugs.

The following drugs are no longer made: Dopram Drops and PregSure BVD vaccine.

Dopram is an effective respiratory stimulant for lambs as it gets absorbed through the lining of the mouth and opens up the airways. It is still available as a sterile injection that seems to work well if it is dispensed into a dropper bottle for sub lingual use.

PregSure was Pfizer’s BVD vaccine which they withdrew last year because of the bleeding calf scare.

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