Ram sales are an exciting time of the year – there is the opportunity to bring in new genetics to improve your flock and the chance to catch up with friends old and new.

However, there is also the potential to buy in more than you intended. Even rams which look their best could be carrying infections or infestations which could cause huge problems on your farm. There are things you can do to reduce the risk to your flock.

Quarantine

Keep newly purchased rams separate from your main flock for as long as possible so that any problems can be identified and, if possible, treated before they have access to other sheep.

A quarantine worming programme is essential to prevent anthelmintic resistant worms being introduced to your flock. Two different wormer groups should be used one after the other.

The gold standard advice from SCOPS is to use both a group 4 (Monepantel) and group 5 (Derquantel) wormer. These are the two newest wormer groups and most likely to remove all worms from newly purchased rams.

The animals should be kept off grass for 24 hours after treatment then turned out to a field that is known to be contaminated with worm larvae. A field that has been grazed by lambs over the summer would be a good option.

Sheep scab remains a problem throughout the UK. It takes several weeks after infection for sheep to become visibly affected by sheep scab so prevention is much better than cure. OP sheep dips or injectable products are available to treat any sheep being brought on to your farm. OP sheep dips have the advantage that they will also prevent lice being introduced.

A blood sample is available which can detect antibodies to the sheep scab mite and can show evidence of infection before visible problems occur. This can be a useful tool but if the ram has become infected with sheep scab on sale day then it will still take some time for the antibodies to develop.

A lesser known problem is scrotal mange. This is caused by the Chorioptes bovis mite. This mite lives on the haired areas of the body rather than in the fleece and can cause irritation and thickening of the scrotal skin. In turn, this warms the testicles and can cause infertility.

The injectable macrocyclic lactones which are effective against sheep scab are not fully effective against scrotal mange. Organophosphate sheep dips do not have a licence for treating this problem but do appear to be effective.

Feet problems

Any purchased animal could be carrying strains of foot rot infection or contagious ovine digital dermatitis which have not been present on your farm before. While in quarantine, the feet of all purchased animals should be inspected and any problems treated before the ram is introduced to the main flock.

Other infectious disease.

Maedi Visna (MV), Johne’s disease, Border disease, CLA and Jaagsiekte (also known as Ovine Pulmonary Adenocarcinoma, OPA) can all be introduced by purchased rams.

The best way to avoid introducing MV is to purchase from accredited disease free flocks at an accredited sale. Where this is not possible the ram should be tested while in quarantine and again 6-12 months later to ensure he is not carrying infection.

Johne’s disease is more challenging. A blood test is available to check for antibodies but infected animals can test negative for prolonged periods after they become infected. You should ask the vendor about the disease status of the flock you are buying from.

Border disease can cause poor fertility in a flock and can cause immune suppression. Like BVD in cattle persistently infected animals occur. A blood sample can be tested for Border Disease Virus to ensure you have not bought in a persistently infected animal.

All purchased rams should be inspected for lumps, especially round the head neck which suggest CLA might be present. Rams can also be blood sampled to reduce the risk of introducing infection.

Jaaksieke or OPA is becoming well recognised as a major problem for the sheep industry. Ultrasound scanning of the lungs can be carried out before or after sale to avoid the purchase of an animal which has large lung tumours at the time of sale.

Unfortunately this method cannot say for sure that the ram is not infected. If scanning has been carried out pre-sale it is worth asking about the results for the other rams in the group. If infection has been found in the group then all rams in the group must be regarded as high risk.