Meeting on Herd Health during Housing
We are holding a meeting on the health of cattle during the housing period on Tuesday 13th October at 7.30pm in The White Horse Hotel, Strichen. The topics covered will include a BVD update, liver fluke, pneumonia, digital dermatitis, worms and lice. We will have another meeting during the winter on calving topics. The coming meeting is being sponsored by MSD and stovies will be provided. For catering purposes please let us know if you would like to attend by calling the practice on 01771 637219.
BVD testing reminder for store producers
Annual BVD testing is compulsory for all Scottish breeding herds. If you are selling stores before they reach nine months old and your herd is currently classed as Negative the options are as follows:
· Blood test ten calves aged 6-9 months old from each separate group for BVD antibodies
· Test every calf born or brought into the herd for virus (using either ear tissue at any age from birth or blood samples from one month old)
· Test all cattle in the herd for virus.
If your herd is currently classed as Not Negative then all cattle leaving your herd need to be individually tested as negative for BVD virus before sale (unless they are being sold as finished). If an animal tests as negative for the virus (also known as antigen) then its dam is assumed not to be a PI (Persistently Infected) animal so it can be sold without testing.
If cattle are purchased from an untested herd (e.g. a non-breeding dealer’s herd or from a non-Scottish herd) and enter a holding with a breeding herd then the bought in cattle need to have either been previously tested as negative for BVD virus or be tested on arrival in their new herd.
If your herd is classed as having Negative status and your calves remain in your herd until they are over nine months old it is best to wait until they are over that age before testing them as only five need to be tested per group and it reduces the risk of detecting antibodies that have been derived from colostrum and could still be present in the blood stream at a low level.
If you are unsure as to what your herd’s BVD status is you can check on the internet on the ScotEID website by entering your holding number (www.scoteid.com). We can also check for you or contact the BVD helpline on 01466 794323.
Please note that there are different types of BVD test:
Antibody testing indicates whether or not an animal has been exposed to BVD virus in the past. As BVD virus is very infectious and PI animals shed a lot of virus constantly then testing a proportion of the group is usually sufficient to detect if there is, or has been, exposure to BVD virus in the group.
Virus or antigen testing indicates if an animal is infected with BVD virus. PI animals are virus (or antigen) positive. PI animals do not usually have any antibody to BVD. PI animals are only created before birth. If it is not a PI animal at birth it will never become a PI animal. The virus/antigen tests are very sensitive and can sometimes detect animals that have been exposed to the virus very recently. Therefore if an animal tests as positive for virus/antigen it is recommended to isolate it and retest it again after at least three weeks. If it retests as positive it confirms that it is infected with BVD virus and is therefore a PI animal. If the dam of a PI animal is present in the herd it should be tested for BVD virus in case it is a PI animal.
Liver Fluke in Sheep
October is usually the time of year when acute liver fluke problems start to occur. As this summer has been wet the conditions have been ideal for liver fluke, which has a mud snail as part of its life cycle. It is therefore likely that the liver fluke challenge will be significant this year. Acute liver fluke hits sheep hard due to large numbers of immature flukes migrating through the liver and it can result in sudden deaths or the sheep may be seen as weak for a short time before death. Unfortunately it can result in a number of deaths over a short period and, due to the severe liver damage that is caused, the deaths can continue for a short time even after treatment during an outbreak. It is best to treat sheep (lambs, ewes and tups) for fluke before an outbreak is likely and the best drug for treating sheep this month or next is triclabendazole as it is the only drug that is effective against the very early stages of liver fluke. It is present in Fasinex and also in the wormer/fluke combination treatment Combinex. Unless ewes are in thin body condition or are tightly stocked they generally do not need worming at this time of year and only need to be treated for liver fluke. This is one of the recommendations to try and reduce the risk of wormer resistance developing in the worms on your holding.
Keeping store lambs alive and healthy
If store lambs are of unknown vaccination status it is advisable to vaccinate them with Ovivac P Plus soon after arrival. A two dose course, 4-6 weeks apart, is required. It includes protection against two of the most common causes of death of young lambs: pulpy kidney and Pasteurellosis. If their worming history is unknown it is worth dosing them for worms and fluke on arrival. At this time of year use a product that is effective against the immature flukes i.e. containing triclabendazole (e.g. Fasinex or a combination wormer/flukicide e.g. Combinex). Usually treating them for fluke on arrival and again in January is sufficient if lambs are being sold by early spring but in wet years it may be necessary to dose them for fluke again in November. When dosing for fluke in January using a product that targets the late immatures and adults is sufficient. It is best not to use triclabendazole all of the time otherwise the risk of resistance to it developing will increase. It is also worthwhile considering treating the lambs for scab, especially if you also have a breeding flock. Injectable wormers such as Dectomax Injection, Cydectin Injection and Ivomec Classic Injection target scab as well as worms however some products require two injections to be given if the sheep are showing signs of scab. Another option would be to plunge dip the sheep to prevent scab from being introduced. Dips are also good for lice control. If store lambs are in lean condition it may be worth having some of them blood sampled for cobalt, selenium and copper as they could be deficient in one or more of these trace elements. Running them through a formalin or zinc sulphate footbath soon after arrival is also worthwhile and repeating on a regular basis through the autumn and winter should help to keep footrot at a low level. Always check withdrawal periods before using any products in finishing lambs as some of the injectable wormers and fluke treatments can have lengthy withdrawals.
Catriona Ritchie BVMS MSc MRCVS
Buchan Vets Large Animal Team