Ovine psoroptic mange (sheep scab) is a debilitating and damaging condition caused by a
hypersensitivity reaction to the faecal material of the parasitic mite Psoroptes ovis. Farmers
incur costs from the use of prophylactic acaricides and, if their sheep become infected, they
incur the costs of therapeutic treatment plus the economic loss from reduced stock growth,
lower reproductive rate, wool loss and hide damage. The unwillingness of farmers to use
routine prophylactic treatment has been cited as a primary cause of the growing incidence of …