The effect of jute coats on the heat losses of two breeds of sheep exposed to different environments

Abstract

Experiments were carried out to measure the effects of wearing jute coats on the heat production and external insulation of Blackface and Cheviot sheep during exposure to different types of cold environment. The results showed that wearing coats did not appreciably increase external insulation in cold conditions at wind speeds up to 10 mph when the fleece was dry. In cold, wet and windy conditions, wearing coats prevented moisture from penetrating the fleece of the sheep so that external insulation was 25–27 units when the sheep were wearing coats, but only 15–18 units when they were not.It has been shown that few environments likely to occur in Britain constitute a cold stress for grazing sheep if their external insulation is above 25 units. Wind and rain reduced the external insulation of sheep with full winter fleeces below this value only when they were not wearing coats. It is concluded, therefore, that jute coats have a considerable value in ameliorating the effects of cold stresses of the type likely to be encountered by hill sheep wintered out of doors in the British Isles.