ANIMAL PARASITES OF CATTLE. 



519 



PSOROPTIC MANGE. 



Psoroptic mange of cattle is caused by small mites (fig. 16) which 

 multiply rapidly and are spread from diseased to healthy cattle 

 by bodily contact, or by pens, stables, railroad cars, etc., recently 

 occupied by mangy cattle. Tlie mites attack 

 the skin and cause it to become thickened and 

 covered with crusts and scabs, with a conse- 

 quent loss of hair. Intense itching accom- 

 panies the disease, and affected cattle are 

 more or less constantly rubbing and licking 

 themselves. Psoroptic mange commences at 

 the root of the tail, or on the neck, or withers, 

 and gradually extends over the back up to 

 the head, over the sides, and may finally af- 

 fect nearly the entire body except the legs. 

 In serious cases the skin may become ulcer- 

 ated; the animals are greatly weakened and 

 emaciated, and finally die. By taking scrap- 

 ings from the edges of scabby patches and 

 placing them on a piece of black paper in a 

 warm place the mites may be seen as tiny 

 white objects crawling over the paper, more 

 distinctly if a magnifying glass is used. 

 Mange may be confused with lousiness, ring- 

 worm, or with any condition in which there 



is itching or loss of hair, but if mites are found there is no question 

 of the diagnosis. The disease is worse during cold, w^et weather. 

 Mangy cattle, when on good pasture during the summer often seem 



to recover, but in the fall the disease again 

 appears in a severe form. 



Treatment. — The most generally used and 

 most satisfactory method of treating cattle 

 mange consists in dipping the animals in a 

 ^at filled w^ith a liquid of such nature that 

 it will kill the parasites without injuring 

 the cattle. Yats for dipping cattle are built 

 of wood, stone, or concrete, and vary in 

 length from 30 to 100 feet or more. They 

 vary in width from 3 to 7 feet at the top, 

 and 1^- to 3 feet at the bottom, and the depth 

 may be from 7 to 10 feet. A narrow chute 

 through which the cattle are driven leads 

 to one end of the vat, where a steep slide pitches the cattle into the 

 dipping fluid, through which they swim, and climb out of the vat at 

 the other end, which is built sloping and provided with cross cleats to 



Fig. 14. — Red louse (Tric7w- 

 dectes scalat-ls) of cattle. 

 Enl.nrged. (From Bureau 

 of Entomology.) 



Fig. 15. — Egg of short- 

 nosed blue louse (Hwma- 

 topinus eurystermis) at- 

 tached to a hair. Enlarged. 

 (Prom Bureau of Ento- 

 mology.) 



