Fog Fever

There are several things that I still do not understand about Fog Fever. It has always been a mystery why Hereford and Hereford cross cows are the most prone to develop it. In a mixed group of cattle it is always the Herefords that develop it, the rest carry on grazing as if nothing was happening. It does not seem to occur in dairy cows, it will occur in dairy cows that are no longer visiting the parlour to be milked but are now rearing calves. Fog fever is an acute allergic reaction. It seems to be triggered at this time of the year by a fungus on the pastures. It happens when adult cows move from stale pasture onto new field where the grass has not been grazed for some time. It starts on still days when there are cobwebs on fences and hedge rows. The risk factors are about at the moment so try to avoid sudden pasture changes if you have susceptible animals.

Dramatic Symptoms

Often the symptoms are dramatic. Affected animals get a massive build up of fluid on their lungs. Sometimes they are not able to move from the pasture as they are so breathless. Sometimes they are found dead. Usually several animals are affected. Animals that have been treated for the condition in previous years are particularly at risk.

It is not clear why this condition is not as common as it used to be. There may be a connection with migrating lungworm larvae as cattle with husk show similar if less severe symptoms. It might be that the larvae can trigger the condition and that modern wormers help to stop that happening. Also there are host of non steroidal drugs that we use to treat respiratory conditions in cattle now but somehow none of them are as effective against Fog Fever as intra venous steroids. There is a risk that this will cause a pregnant cow to abort, but that does not always happen. As well as the steroids affected animals should be housed in a quiet environment and fed anything that is not grass. Recovered animals must be kept away from lush grass and are better to go onto a field that has been grazed by sheep at first to limit their grazing.

Avoiding Calf Stress

Calves that are coming into buildings need careful handling, they can cope with only so much stress. If you have problems with Respiratory Syncitial Virus and Infectious Bovine Rhinotracheitis try to complete the vaccination course before they are housed. This might mean that they will need to start a month or more before they come in. One of the IBR vaccines can be given as an intramuscular injection which might be easier for bigger cattle. It takes a little longer for the vaccine to work if it is injected, but it might be worth while if you do not have to vaccinate and house on the same day.

Gentle Weaning

Also it is often tempting to house the group and wean them at the same time. This is not a good idea unless there are only a few animals involved and you do not get older calves blowing. It is important to worm calves before they are housed. The tendency is for the winter to come slowly so many pastures will have a significant worm infestation at this time of the year. Pour on wormers are useful because they are easy to apply and should not stress the animals, they have a residual activity so should go on killing lungworm for several weeks. They treat lice as well and should stop that developing when the calves are housed. Remember there are new rules for administering micotil now. Micotil was so popular for on farm use because it was effective and you will not get such good results with the alternatives that you can still use.

Preventing Dermatitis

Digital Dermatitis is caused by a spirochete bacterium. Often in the summer the lesions will not look very significant, but they are intensely uncomfortable. In the winter the infection becomes established in wet areas in slurry or around gateways and water troughs. Most animals seem to get some immunity if they have had the infection at some stage they are less likely to get a recurrence of the lameness unless conditions are very wet. If you regularly get dermatitis in your young cattle in the winter it might help to use an antibiotic footbath now for all of the adult stock before it gets too wet and before the herd is housed. This will have the effect of reducing the infection in the cows and should mean that you will go further into the winter before you have to treat many lame ones.

Micro Chipping Horses

There is still a lot of talking going on about identifying horses. The compulsory passport scheme has been operating for some two years now, but it has done little to stop the theft of animals or to help trace the owner of a horse found straying. To any one who treats horses it is apparent that there are a whole host of passports in different formats that have been issued. There are more than seventy agencies issuing passports for horses so it is difficult to discover if a horse has the correct documents. It is a bit unfortunate that when passports were brought in they did not implement the requirement for compulsory microchips. When a horse is micro chipped it is registered on a database so that with a few clicks of the button on a computer mouse you are able to discover details of the registered owner. This is a fairly fool proof system. At shows and events the microchip is read and compared to the presented passport. There is then no need to examine markings and whorls if the numbers match. If all horses were mico chipped as foals it would be difficult to disguise there identity and help to stop them being stolen. It would also help with welfare investigations as so many are not able to proceed because the owner of the animals cannot be traced.

Recovering Microchips

As I understand it one of the things that is being discussed is how micro chips are to be recovered from horses that have died. There may be an argument for doing this for animals that are destined for human consumption and there is no reason why they should not be detected and recovered at slaughter. Microchips are very small and it is difficult to find them. It is highly unlikely that one could be removed from a dead horse and used for fraudulent purposes. When a horse is lost there should be no reason why the passport cannot be returned and the status of the microchip changed so that it cannot be used again.

Monitoring Waterfowl

As far as I can discover there have been no cases of Avian Influenza discovered here in wild birds this summer. It is good that we have been able to avoid this disease as it continues to cause problems in Europe. Germany has had over forty outbreaks during the summer. The new plan is to monitor wild birds from areas of the country that are thought to be particularly at risk. We are on the edge of a surveillance zone so deaths of single swans or three or more geese, ducks or gulls should be reported to the DEFRA helpline.

Return to Newsletters