What is Maedi-Visna?

Maedi-Visna (MV) is a chronic viral disease affecting sheep, caused by the Maedi-Visna Virus (MVV), which belongs to the lentivirus family. It was originally introduced into the UK through imported sheep and has since spread, particularly within commercial flocks.

MV primarily affects the respiratory and nervous systems, leading to chronic pneumonia (Maedi) and progressive wasting (Visna). It is a slow-developing disease, with symptoms often taking years to appear.

Although the virus is not zoonotic and does not affect humans, it is highly contagious between sheep. Infected animals can spread the virus before showing any visible signs, making control particularly challenging.

Clinical signs of MV

Because MV develops slowly, symptoms may not be immediately obvious. Over time, affected animals may show:

• Progressive weight loss and poor body condition
• Difficulty breathing or increased respiratory effort
• Reduced milk yield and fertility
• Lameness in some cases
• General decline in productivity

These signs often appear gradually, which can allow the disease to spread within the flock before it is detected.

Managing MV in the UK

In the UK, measures are in place to help control the spread of Maedi-Visna, focusing on monitoring, testing, and managing infected flocks.

Farmers are encouraged to test animals that show signs of illness or abnormal behaviour. Early detection plays a key role in reducing the risk of wider infection within the flock.

The importance of biosecurity

Strong biosecurity is one of the most effective ways to reduce the risk of introducing or spreading MV on your farm.

• Quarantine incoming sheep before introducing them to the flock
• Disinfect equipment and facilities regularly
• Only introduce animals from known, healthy sources
• Maintain high standards of hygiene across the farm
• Minimise unnecessary contact with other livestock

Good animal husbandry practices also play a role in reducing susceptibility to infection. Improving ventilation in sheds and ensuring adequate nutrition can help reduce stress and support immune function.

Why accurate records matter

Managing diseases like MV requires clear and accurate records. Keeping track of treatments, flock numbers, and animal movements is essential for traceability and compliance.

In the event of a disease outbreak or restriction, having reliable records allows farmers to quickly identify, isolate, and manage affected animals.

How Herdwatch can help

Herdwatch makes it easy to manage flock records, helping you stay compliant and improve overall farm management.

Keep medicine records organised

Scan and record medicine purchases directly into the app and log treatments against individual animals, ensuring a complete and accurate treatment history.

Track flock numbers and movements

Record animal movements quickly and accurately, helping maintain full traceability across your flock.

Stay prepared for inspections

Store all records digitally and generate reports instantly, making farm audits and inspections much easier to manage.

Save time on paperwork

Digital records reduce the time spent on manual paperwork, allowing you to focus more on managing your flock.

Protect your flock with better management

Maedi-Visna is a long-term disease that can have serious consequences for flock health and productivity. By combining strong biosecurity, early detection, and accurate record keeping, farmers can reduce the risk and limit its impact.

A proactive approach helps safeguard animal welfare and supports more resilient and productive farming systems.