Thursday, May 20, 2010

Blue Tongue and Other Ovine Afflictions

The first few months on the farm were charactersised by an inordinate amount of rain - 431mm for the first four months of that year. To put this into perspective, this is a good average annual rainfall for the area. The consequence was an explosion of diseases of the sheep related to the wet conditions. "Bromme" or maggot flies soon made their appearance. The Afrikaans slang word is derived from the characteristic buzz the fly makes. It is highly distinctive in colour, being a metallic green.

Blue Tongue made its appearance as well. This latter disease is a virus spread by midges (culicoides) or "miggies". It derives the name from the characteristic cyanosis of the tongue. There is no cure - the vet advised that the affected animals should be kept hydrated and penned in the dark, until the symptoms had dissipated. All this made for a rather hectic few weeks, as the number of sheep needing treatment increased. Fortunately the number of fatalities was limited, and the crisis soon passed.

As an interesting aside, one of the effects of 'climate change' is the occurence of Blue Tongue in Europe - it was first reported in 2006. In 2007 Britain reported its first case of the disease. It has now spread as far north as southern Sweden.

Blue Tongue is not a highly visible disease; the same cannot be said of maggot fly strike! The fly is attracted to wet patches on the skin of the sheep, usually but not always in the area of the crutch of the animal. The fly lays innumerable eggs which hatch, in short order, into live larvae (maggots) that literally devour the living flesh of the sheep. Keeping a close lookout for those so infected is an integral part of the day to day managment of the flock. Treatment is usually effected by shearing the infected area, washing the area with a strong insecticide and then dusting with an antibiotic. A truly nasty parasite!

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