Inducing permanent baldness of local areas on animals - esp. sheep, by cryogenic destruction of hair follicles

摘要

Permanent baldness over a predetermined area of the skin of an animal is induced by terminating the activity of hair follicles in this localised area. The area is first sheared and then a cryogenic fluid is applied to the skin in this area, within a cover which prevents the fluid reaching adjacent areas. Any sensitive parts within the cover, esp. the perineal regions, are fully protected from contact with the fluid. The cryogenic fluid must produce a skin temp. below -30 degrees C, pref. well below -80 degrees C; sprayed liq. N2 at -196 degrees C is partic. suitable. For treating an area in the region of the tail and rump of a sheep, a dome-shaped cover is used to enclose the area, and a central protection tube prevents fluid reaching the perineal regions when the fluid is sprayed into the cover. For this purpose, the tube is pref. of a heart-shaped cross-section. Process is used to prevent hair becoming matted around the rump and tail with material evacuated by the animal and the encouraging infestation by egg-laying flies. Baldness in these areas also improves fertility of ewes and produces a clean fleece when sheared. The process saves labour by eliminating partial shearing several times each year. It can also be used to eliminate hair permanently from areas around an animal's eyes and penis in the interests of hygiene.