Maedi-visna is debilitating viral disease that can undermine the economic viability of a sheep flock.
The name Maedi-Visna is an Icelandic description of the two major forms of the disease(Maedi=progressive pneumonia and Visna=wasting). Although it is ultimately fatal, most of the economic loss attributed to this disease is due to decreased milk production; lowered weaning weights; increased incidence of severe arthritis and wasting; higher than average number of respiratory infections; and decreased ewe fertility. In one study, it was found that 66% of healthy appearing, Maedi-Visna positive ewes had udder lesions and their lambs had lower than average weaning weights. The disease is common in many sheep producing countries, and 70% of flocks tested in Ontario in the late 1980's had at least one positive animal. There is no cure or treatment for the disease, however, there is a reliable blood test that can identify infected animals.
What is Maedi-Visna, What causes it and How Will It Affect Your Flock?
Link to a list of producers who are currently participating in health programs