. Common diseases of farm animals. Veterinary medicine. 242 PARASITIC DISEASES than tick, as its entire life is spent on the body of a sheep. The general color of the body is brown. The legs are stout, covered with hair and armed with hooks at their extremities. The mouth parts consist of a tubular, toothed proboscis with which the para- site punctures the skin and sucks the blood. Within a few hours after birth, the larvae develop into pupip, which are hard, dark bro'wn in color and firmly glued to the wool. The young louse- fly emerges from the pupa in from three to four weeks. The sheep-tic
. Common diseases of farm animals. Veterinary medicine. 242 PARASITIC DISEASES than tick, as its entire life is spent on the body of a sheep. The general color of the body is brown. The legs are stout, covered with hair and armed with hooks at their extremities. The mouth parts consist of a tubular, toothed proboscis with which the para- site punctures the skin and sucks the blood. Within a few hours after birth, the larvae develop into pupip, which are hard, dark bro'wn in color and firmly glued to the wool. The young louse- fly emerges from the pupa in from three to four weeks. The sheep-tick is a very common external parasite. The adult parasites and the pupaj are large and easily found. When badly infested with ticks, a sheep will rub, dig and scratch the skin and fleece. This results in pieces of wool becoming pulled out and the fleece appears ragged. After clipping the ticks mi- grate from the ewes to the lambs, which may become un- thrifty and weak. The treatment consists iti dipping the flock in a one or two per cent water solution of a coal-tar dip. Dips containing arsenic are most effective in ridding sheep of ticks. Scabies.—This parasitic disease is one of the oldest and most prevalent diseases of the skin. It is commonly known as scab or mange. The animals most commonly affected are sheep, horses and cattle. The disease is caused by small mites or acari that are natu- rally divided into the t<arcoptes, which burrow under the epi- dermis, forming galleries; the Psoroptes, which live on the sup. Fig. 67.—Sheep scab mite, ventral view. (From Farmers' Bulletin No. 159, United States Department of Agriculture.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Craig, Robert Alexander, 1872-. Philadelphia London, J. B. Lippincott company
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Keywords: ., bookpublisherphilad, booksubjectveterinarymedicine, bookyear1919
