Fifth of sheep flocks positive in maedi visna tests

Commercial sheep farmers must be aware of the “hidden menace” that is maedi visna (MV), warn leading health experts.

Scottish Agricultural College (SAC) advice is that farmers should run at least one diagnostic screening each year if they feel their flock is underperforming by sampling 12 older/thinner sheep.

See also: How maedi visna led to whole flock cull

Since 2012 MV blood screening has found 20% of surveyed flocks to be infected with the costly and crippling virus.

Of those flocks affected by the disease, infectivity levels were eventually revealed to be up to 70%.

A new SAC video explains the challenges of MV – “you cannot tell which they are by just looking at them”.

Watch the SAC video on MV and see infected sheep:

The SAC’s stark warning estimates losses of up to £50,000 in a 1,500 ewe flock from the condition, which veterinarians believe is spreading within the UK.

MV Signs

  • Thin ewes
  • Drop in milk yield
  • Increased mortality rates
  • Lambs not thriving
  • Increased mastitis
  • Reduced fertility


A diagnostic screening package for 12 (older/thinner) ewes is available for £37 (plus VAT and veterinary visits and sampling charges).

More information is available from the SRUC website.

Samples can be sent to SAC Consulting Veterinary Services, Greycrook, St Boswells, Roxburghshire TD6 0EQ.

See also: SAC launches new maedi visna test package