Infectious Diseases in Sheep

Rose Young BVM BVS MRCVS, Molecare Veterinary Services

Those involved in the sheep industry may be aware of some of the infectious diseases that can affect our national flock; you will have seen the “MV accredited” sheds at regional livestock shows, and many farms have unfortunately seen the consequences of Enzootic Abortion, often via bought-in animals. But how much do you know about these diseases in sheep? And how much risk do they pose to the average farm? This short article aims to answer those questions, and provide some practical solutions to help you and your vet minimise the risks to your stock.

‘Hidden’ diseases

There are several infectious diseases affecting sheep which could be described as hidden; in which an infected animal may appear normal for a long period (sometimes years) before showing signs of disease, or those which result in animals becoming permanent “carriers” of disease. These conditions pose a problem, in that there may be no outward signs at all in the affected animal, or simply vague symptoms such as weight loss or chronic mastitis, which can easily be put down to other causes. If you are buying in animals without knowing their disease status, you could be buying in all kinds of problems. Similarly, if you don’t know the status of your own sheep, your own home-bred “closed” flock could be harbouring diseases which may affect fertility, growth rates and overall health.

Investigation and control

The table above shows the breakdown of key information on eight specific conditions, but you may notice that control strategies are similar across many of these diseases. The most important factors come down to three main points;

Know your status – annual or biannual cull ewe blood testing can be an excellent marker of the range of infectious diseases circulating in your flock, be sure to test abortions and seek advice from your vet if you suffer unusual production losses or health issues in the flock. MV and EAE accreditation also available.

Purchase policy – unless you have a completely closed flock, you risk buying in disease with every purchase, either buy from farms known free of disease, or arrange for a sample of animals to be tested at the source farm before entering your holding, rams especially. Quarantine and testing after arrival is an option if necessary.

Quarantine/biosecurity protocol – some (not all) of the diseases discussed above can be limited by using a sound quarantine and strategic treatment protocol, discuss with your vet to see what’s needed on your farm. Robust biosecurity prevents access between your stock and neighbouring farms and should be a priority.

For more information phone us on 01392 872934.