This summer the internal and external parasites have run riot and there have been reports of a worm infestation in lambs that you might miss because it does not give the usual symptoms of scouring and loss of condition. Heamonchus contortus is a strongyle worm that sucks blood from the true stomach or abomasum. They can quickly build up to large numbers. Eggs do appear in the faeces, but it is not possible to distinguish them from the other strongyl worm eggs, so it can be deceptive as to how serious the infestation is likely to be. Lambs with this parasite loose a significant amount of blood and become anaemic. The membranes of their eyes go white, the heart rate increases and they develop a swelling under their jaw. The symptoms come on quickly; often the first thing that is noticed is that lambs will be found dead on the field. It is too easy to assume that sudden deaths in lambs are associated with pasturella or a clostridial disease so the actual cause can easily be missed before significant losses occur.

Haemonchus responds readily to the worm drenches or injections. There have been reports of resistance in some areas to the white benzimizole wormers so it might be better to avoid those if you have had significant losses. You might be restricted a bit by the withholding times of the wormer that you can use if your lambs are close to their finishing weight. I have always though of this parasite as a summer problem more in the south of the country and it is only rarely that it has had a significant impact here.

The Ringworm vaccine for calves has finally returned. Intervet have sorted out their production problems and are able to supply the vaccine again. Ringworm has always been a difficult disease to control. In the past there were aerosol sprays and a powder that you could mix into the feed over the course of a week to stop the infection. All of these have been stopped for food producing animals now. Mycophyte is still available, but it can take some time to spray on to the calves and often has to be repeated three or four times before it stops the infection.

Once a fungal infection is established in a building it can be very difficult to get rid of it as it tends to lodge in cracks and crevices and can persist on damaged wood work. Calves with ringworm never grow as well as they should, they spend too much time rubbing and scratching rather than eating and growing. Eventually after the infection the animals will develop immunity to the fungus, but this will not normally happen until the calves have had a summer out in the sunshine. Even then you cannot be sure that some lesions will not recur in older animals when they calve or when they are mixed together in different groups.

Ringvac is a live vaccine so it must be stored in a fridge. You have to mix a liquid with a tablet to get five doses of the vaccine that should be used straight away. The injection is given into the muscle on the upper half of the neck and a second dose is administered after two weeks to give life long protection against this disease. When you use the vaccine it is not necessary to try and disinfect the buildings that are used by the calves. The contamination in the buildings will gradually die out as there will be no infected animals to keep the disease active. Ringvac is particularly useful for calves that are sold as stores and on farm that sell newly calved heifers as this is one of the times when the lesions suddenly appear and spoil the animals that you have got ready for sale.

The Intervention Board has changed their telephone numbers for the Fallen Stock and for the Casualty Slaughter Scheme. The new number for both of these services is now 0800525890. This does not seem to be a change for the better. The old system was working well, now we sometimes have to wait for more than thirty minutes to get a reference number for the forms. They do not seem to have anticipated the demand for this service.

Some farms are having problems with lame cows and there seems to be a large number of lame sheep about at the moment. Foul and scald are partly caused by the feet being wet most of the time so that the infectious organisms can readily get established in the skin between the toes. The feet will not be in the best of conditions to go through the winter if the wet weather continues so it might be better to start using a formaldehyde footbath now to clear any remaining infection from the feet and harden them off before the winter comes.

September is the best month to plan your vaccination strategy to protect your calves for the housing period. Calves born outside during the summer would have little opportunity to build up a significant immunity to the respiratory pathogens. They might have some contact with older stock, but it is difficult to introduce them to housing gradually. What tends to happen is that they are out one day full time and in the next. They then have to cope with a new environment and compete for feed and space in the building. Often it is not the lack of ventilation that triggers an outbreak of pneumonia but the stress of housing and a new environment.

On most farms the infections that cause the most damage are Respiratory Syncitial Virus and Pasturella. There are vaccines to combat both of these infections. Two doses are needed about a month apart and you will not get full protection developing until two weeks after the second injection. The trick is to finish the vaccinations well before the cattle are housed. It is not always possible to anticipate the exact time when the calves will come into the buildings so it is better to get it sorted well in advance. There is no problem keeping them out longer if the weather conditions are favorable.

Just a reminder that the Sole Occupation Licensing System is still working so if you have rented or own any ground away from your farm and have stock there you can readily link them together. This means that you do not have to record any movements as long as you do not exceed the total stock numbers on the License. Also do not forget to keep the License up to date if there are any fields that you no longer use.

Let me introduce you to Alison our new vet who has just graduated from Edinburgh University. Alison comes from Weston under Redcastle and is familiar with our part of the world. Alison is interested in Mixed Practice and I am sure you will meet her in the near future.

Return to Newsletters