Maedi Visna is caused by a virus which is very contagious, there is no cure or vaccine and therefore it is fatal. Outbreaks have been witnessed throughout the country and of the national flock there is estimated to be at least 100,000 sheep infected.
This virus has a great impact on your flock. After clinical signs develop t
here is a 10-20% adult mortality. Increased lamb mortality results as well as decreased growth rates from reduced colustrum intake. Arthritis and reduced fertility occurs and causes an increase in culling rates.
Sheep do not normally show signs until they are adults as the virus has a long incubation period. The main clinical signs are:
It can be transmitted in a variety of ways:
Shedding of the virus in Milk, Colostrum, Faeces and respiratory secretions:
Lambs can be infected by drinking their mother's colostrum or milk. A lamb stealing milk for another dam is also at risk of infection.
Other sources are contaminated water or feed when uninfected sheep are housed or at pasture with infected sheep.
Maedi Visna (MV)/Caprine Arthritis Encephalitis (CAE) Accreditation Scheme
The Scheme is open nationally to all flock keepers who intend to conform to the rules and regulations of the membership. MV accredited sheep must be kept separately from non accredited sheep at all times. Membership is at the discretion of SAC Veterinary Services. There are many benefits of joining the scheme:
Reduces the risk of your flock getting the virus
Allows you to attend shows and sales with your flock
Allows you to export to Maedi Visna free countries
Allows you to advertise your flock as MV accredited
Adds value to your flock and enables you to sell to purchasers who have MV accredited flocks
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.
If you are interested in becoming MV accredited, please contact us at the surgery and we can talk you through it
Maedi Visna (MV) Monitoring Scheme
A MV monitored scheme is available for commercial flock masters who are unable to totally isolate their flock.
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 1 day).
A flock can become part of the monitoring scheme once it has passed one qualifying blood test.
Once MV monitored a proportion of the flock is blood tested every 2 years and certificates are issued indicating MV monitored status.
It is a low cost scheme and helps identify flocks that have been tested free from the virus but total separation is not possible. It enables farmers running closed flocks to make sure that they are not infected and ones with open flocks to check any incoming sheep. It also allows you to advertise to potential buyers that your flock is MV monitored. Keepers of MV accredited pedigree flocks can also use the monitoring scheme to check their commercial flocks as part of a disease prevention programme.
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