Maedi Visna (MV) Monitoring Scheme

The Scheme is open nationally to flock masters who undertake to abide by the rules and conditions of membership. Membership is ultimately at the discretion of SAC Veterinary Services.
The monitoring scheme is not equivalent to the accreditation scheme.
MV accredited sheep must be kept separate from all non accredited sheep/goats (including MV monitored sheep) at all times. Likewise monitored sheep must not have prolonged exposure to non accredited sheep/non monitored sheep (in the same field or building for more than I day).
A flock can become MV monitored when it passes one qualifying blood test.
Once MV monitored a proportion of the flock is blood tested every 2 years and the member is issued with certificates of MV monitored status.
The scheme

• has been designed to identify commercial flocks that have been tested for freedom from maedi visna but where total segregation of the flock is not practicable
• has a low cost scheme
• enables flock masters of "closed" commercial flocks to check that their flock is not infected
• enables flock masters of "open" flocks to monitor incoming animals
• provides a source of tested commercial animals
• members have the opportunity to advertise to potential purchasers that the flock is maedi visna monitored
• is a valuable scheme for flock masters who already have an MV accredited pedigree flock and who would like to monitor the commercial flock as part of their disease prevention programme
• may be added on to the Premium Health Scheme (Enzootic Abortion of Ewes accreditation scheme)

Maedi Visna (MV) is a viral disease which occurs in most sheep producing countries.
Maedi visna has been in Britain for approximately 20 years. The disease was originally brought into this country by sheep imported from the continent. It is estimated that at least 100,000 sheep are now infected in the national flock and clinical outbreaks are being reported from all over the country.
The Maedi Visna Accreditation Scheme is a national voluntary scheme which exists to prevent maedi visna disease in sheep. It is run by SAC Veterinary Services and has around 3,500 members.
MV is a chronic disease of sheep caused by a retrovirus. The name derives from two Icelandic words which describe the main clinical signs of pneumonia and wasting.

• maedi which affects the lungs
• visna which affects the central nervous system

How does it show itself?

Maedi visna infects sheep at any age (mainly lambs but the clinical signs of the disease are usually not seen in sheep under 3 years). After a long incubation period the following clinical signs can appear:

• pneumonia
• progressive paralysis
• wasting
• arthritis
• chronic mastitis

How is it transmitted?

• Lambs suckling infected milk
• Close contact and inhalation via droplets from the nose and mouth
• Cross contamination of blood from punches and needles

Maedi Visna - the facts

• long incubation period
• highly contagious
• difficult to diagnose
• no cure
• no vaccine
• fatal

What is the potential economic impact?

• 10-20% adult mortality after the development of clinical signs
• Lamb mortality and reduced growth rates due to lack of colostrum/milk
• Increase in culling rate
• Incidence of arthritis, premature births and reduction in conception rates

Case study
A recent outbreak on one lowland farm resulted in:

• 68% of the flock becoming infected
• 14% adult mortality rate
• 30% of the potential lamb crop lost
• Cost of MV infection nearly £32 per ewe

The entire flock was slaughtered!
Can you afford to take the risk?

Maedi Visna (MV)/Caprine Arthritis Encephalitis (CAE) Accreditation Scheme

The Scheme is open nationally to flock masters who undertake to abide by the rules and conditions of membership. MV accredited sheep are kept separately from non accredited sheep at all times. Membership is ultimately at the discretion of SAC Veterinary Services.

Benefits of the scheme:

• Helps you to reduce the risk of your flock contracting the disease
• Allows you membership of an elite nationally recognised health scheme with the backing of SAC Veterinary Services
• Enables you to attend shows and sales from which your animals would otherwise be barred
• Allows you to export to certain countries free from maedi visna
• Gives you the opportunity to advertise to potential purchasers that your flock is MV accredited
• Gives added value to your flock by enabling you to supply purchasers who demand MV accredited stock

A flock can become MV accredited when it:

• Passes two qualifying blood tests between 6 and 12 months apart
• Has certification from a vet that the holding can comply with scheme rules and conditions

Once MV accredited, a proportion of the flock is blood tested every 2 years and the member is issued with certificates of status for selling or moving scheme sheep. Shows and sales are licensed to provide space for MV accredited sheep.
An MV monitored scheme is available for commercial flock masters who are unable to totally isolate their flock.