Look out for Fog Fever

Many parts of our area are still dry and grass growth has been slow in some places. These are unusual conditions and they may cause problems with livestock as the grass comes back late in the season. Many cattle are still on bare pastures and care must be taken when they move onto better grazing. Hereford cows are particularly prone to developing Fog Fever. For some reason they seem to react to a fungus that grows on pastures and this can cause a severe reaction in their chest. Once fluid starts to build up in the lungs it can severely reduce the oxygen carrying capacity of the blood and lead to respiratory failure.

Make them move

It is important to keep a close eye on susceptible animals. You should see them at least twice each day and take time to get all of the cows to move as affected animals tend to stay in one place. It is difficult to spot them in the early stages of the condition when they are able to respond to treatments. Because this is a severe allergic type reaction affected cows need a steroid injection to stop the changes in their lungs. With care it is usually possible to move treated cattle away from the affected fields. It is usually better if they can be housed for a while to give them a chance to recover.

The Orf Vaccine is back

It has been a difficult summer on some sheep farms as there were no supplies of  Scabivax Forte for most of the year. Several farms that have regularly vaccinated had clinical cases to deal with. Sheep do not get any lasting immunity from orf and they will not pass on any protection to their lambs. If you have had some orf this year the chances are things will be worse next time and it would be better to use the vaccine this winter to clear up any lasting infection. The virus will survive as small scabs on the udder that will spread to the mouths of new born lambs that have no resistance to the infection.

Treatment Options

Scabivax Forte is a live vaccine that is scratched onto the surface of the skin usually high up on a front leg to give the ewe a mild dose of the infection so they will shed any residual scabs that they might have. The manufacturers recommend that the vaccine is used at least two months before the expected lambing to prevent any infection being spread from the vaccination sites to the new born lambs. The alternative way is to vaccinate the lambs when they are first born, but this involves several sessions and using more vaccine.

Acorn Poisoning

Yesterday I was walking by the canal near Ellesmere and I couldn’t help noticing that in several places the tow path was carpeted with fallen acorns. These can be a real problem for cattle particularly when the ground is dry and there isn’t much grass available. Most animals will not take acorns as they have a bitter taste. Unfortunately some individuals seem to like them and will search for them whatever else is available. Acorns contain an alkaloid that will damage the kidneys.

Don’t miss the early signs

At first affected animals will show signs of constipation, the faeces are often dark and they may be seen to frequently try to pass urine as their kidneys start to fail. There is no specific antidote for acorn poisoning. Liquid paraffin may help in the early stages and it is important to encourage suspect animals to drink as much as possible. Feeding 1kg per head of hydrated lime has been shown to help but it is difficult to organise. Animals that respond to treatments never seem to make a full recovery in the long term as they have to cope with the resulting kidney damage. The best way to stop acorn poisoning is to keep cattle away from the trees when acorns are on the ground by the use of temporary fencing. Some times it helps to spread slurry to discourage the cattle from grazing the affected areas, but this does not work so well when the weather is dry.

Mouth Problems

I have heard reports of several cases of wooden tongue recently. The bacteria that cause it Actinobacillus lignieresii can be found in soil and are usually present in the mouth and nose of cattle. Normally they are not able to get into the deeper structures of the mouth unless the surface has been damaged by thistles or course fodder. The tongue will soon become very swollen and the affected animal will have difficulty swallowing.

Often you might notice the tongue protruding from the mouth and salivation as it is pushed forwards. It always amazes me how well cattle will respond to treatments when they have wooden tongue. It is not usually necessary to administer anti inflammatory drugs as the swelling will start to subside soon after the first injection of antibiotics.

Jaw Infections

There is another mouth infection that is more serious. Actinomyces bovis works in a similar way to wooden tongue but it is a bacterial infection that gets established in the bone of the jaw when young cattle are changing their cheek teeth. Lumpy jaw is essentially an infection of the bone and the lower jaw will become distorted with new bone growth. It is difficult to get antibiotics to clear up this infection completely even if several doses are given. It is not wise to breed from animals with lumpy jaw as it will flare up from time to time and affected animals will not carry much condition.

Dry Feet

During the past two weeks we have been treating several dairy cows and an elderly Charolais bull that have gone down on concrete yards or on a field. It is sometimes difficult to know exactly why cattle slip and fail to get up. Certainly they all seem to have hard feet at the moment and they will soon loose confidence to try and regain their feet if they have struggled and were not been able to stand. It is difficult to advise how best to get the feet soft again. Their might be some benefit from getting dairy cows to walk through a footbath with just water each time they come in to be milked but it will take some time for the moisture levels to build up in the hoof if the dry conditions continue.

Laboratory Closures

Animal Health and the Veterinary Laboratories Agency have announced that they intend to reduce the number of the laboratories that give a full service from sixteen to just eight. In eighteen months time the laboratories in Aberystwyth and Preston will be amongst the ones to offer just a post mortem service with all of the subsequent investigative work being sent to other laboratories. There will be no laboratory in Wales that can fully investigate a disease outbreak. This is a far from satisfactory situation as it will lead to inevitable delays and it mighty be only a matter of time before the affected laboratories close completely. Fortunately Shrewsbury is a relatively new facility and will continue for the time being but nothing is certain any more.

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