Fly Control

So far this has been a very dry and early spring that has been good for the late lambs and good for the cattle that have been longing to get out into the fields. Whatever happens from now on dry or wet we must be aware that the flies, even after a very cold winter have got off to good start. They may not be a problem at the moment, but when you consider that each of those flies that you see on your cows can lay up to one thousand eggs that will reach the adult stage within a week. It is a good idea to do something to control the fly population. The deltamethrin based fly products such as Coopers Spot On and Butox Swish work because they contain an insect growth regulator that prevents the eggs from hatching. They do not kill the flies directly but numbers will dwindle if they cannot be replaced. Spot on products work well for up to ten weeks when the weather is dry so now is the time to start. The chances are this will be a bad year for flies it is too late to start treatments once there numbers have reached a peak. The advice is to start preventative treatments when night temperatures are above 4.5º C so I guess now is a good time to make the first application

Investigating Unexpected Deaths

The Animal Health and Veterinary Laboratories Agency Laboratory in Shrewsbury take in samples from Shropshire, Staffordshire and from the whole of North Wales. Because of their pricing policy, they are now very expensive, it is only occasionally when there is a real need that we send in animals for post mortem. Some post mortems are paid for by drug companies investigating unexpected deaths or monitoring the efficacy of their products. In view of this it always surprises me that most things we send in still get a mention in their monthly newsletter. I have no idea how many investigations are carried out at the laboratory on the days that they are open I suspect it is not that many.

Cattle Post Mortems

Part of the remit of Animal Health and the Veterinary Laboratories Agency is to conduct scanning surveillance, that it to monitor the levels of animal disease in the country and to look out for emerging diseases and conditions such as Neonatal Pancytopaenia in dairy calves. I should imagine most farmers would think twice about taking abortion samples to Shrewsbury if you happen to be lambing ewes on the Llyn Peninsular in North Wales. Last year 800,000 cows were known to have died on farms in England and Wales. Less than 800 of those deaths were investigated by samples of any kind taken to find out why they died. The majority of the investigations were carried out on dairy cows and their offspring. When you consider that even then no diagnosis is made on thirty percent of the post mortems many incidents go undetected.

Preventing the Loss

Cattle that die suddenly on farm are an unwanted loss that in most cases we should be able to avoid. The main culprits are Clostridial disease, especially blackleg, Pasturella, Haemophilus, E coli mastitis and at this time of the year staggers.

There is a big need to find out why these animals are being lost so that we can do something to stop it. It is disappointing that no effort is made to identify farms that are at risk from acute infections. On many farms with a little planning many of these deaths could be avoided with the strategic use of vaccines and other drugs.

Tuberculosis in Cumbria

There are reports this week that officials are mystified by the loss of sixty four cattle to tuberculosis from a farm near Penrith in Cumbria. I understand that they have come from a well managed closed herd that had tested clear of the disease eighteen months ago. Cumbria has up to now been largely free of tuberculosis. There is a small ongoing pocket of infection in the south west of the county, but this is over fifty miles from the farm that has the infected herd. These are big numbers, but I do not think they should come as that much of a surprise. It would appear that most of Cumbria is on four yearly testing. Two years ago all of the farms in Wales were tested for Tuberculosis half of those were then on four yearly testing, but many were found to have reactor animals present. All of Wales is on annual testing now. I remember at the time there was surprise at the levels of undetected infection. Most cattle with tuberculosis will show no outward sign of the disease the infection will soon get established as soon as your back is turned.

Wider Implications

This week cattle on adjoining farms will be tested. To find out the true situation it would be better if all of the cattle in Cumbria were tested this year. Tuberculosis has time and again shown itself to be an unpredictable disease that is out of control, it is far better to monitor it closely rather than try to stop it once it becomes established. This new will also ring alarm bells in Scotland where they is trying to get tuberculosis free status. It will be difficult to achieve this if this outbreak is not brought under control quickly.

Investigating High Cell Counts

Now that the cows are out and the weather is dry it might be a good time to investigate those high cell count cows before the flies start to become a nuisance. This is the time of the year when it should be possible to clear up teat end skin infections. You will be well aware that cell counts can be misleading as they are only a crude indicator of infected quarters. Cell counts of more than 200,000 may not seem to be that high. You must remember that the readings are given for the cow not each quarter so 200,000 means that one quarter is over 800,000 and they need to be investigated if they are high for two months in a row. Some 60% of high cell count cows will self cure within a month of becoming infected. Of the ones that stay high 60% will become chronically infected. The trick is to catch them before this happens. Changes in the quarter may be subtle, first have a good feel of the udder does one of the quarters feel different from the rest? Draw milk from each quarter onto a dark surface to determine if there are any small clots or signs of wateriness or use the California milk test if you have it. Treat all suspect quarters for three milkings and keep an eye on the next milk recording results to check that you have done the right thing. Tackling chronic mastitis takes months not just days. If after regular checking you are still not able to track down the infected quarter continue to monitor until the cow is due to go dry and consider treating with a course of Tylan as well as your regular dry cow tubes

Foot and Mouth Disease

There are reports this week that there is an outbreak of Foot and Mouth Disease in Bulgaria. Let us hope that it is soon cleared up.

Return to Newsletters