518 



DISEASES OF CATTLE. 



as blue lice, and one biting louse {Tnchodectes scalaris), commonly 

 known as the red louse. 



The blue lice (figs. 12 and 13) suck the blood of cattle and are more 

 injurious than the red lice (fig. 14). Unless very abundant the latter 

 cause little injury. If numerous they irritate 

 and worry their host probably more by their 

 sharp claws than by their bites, as their food 

 seems to consist entirely of particles of hair and 

 dead skin. 



Cattle lice reproduce by means of eggs or nits 

 (fig. 15) which they fasten to the hair. The blue 

 lice infest chiefly the neck and shoulders ; red lice, 

 when present, may be found almost anywhere on 

 the body, but are usually most numerous on neck, 

 shoulders, and at the ro(!t of the tail. 



On account of the itching caused by the lice, 

 infested cattle rub against posts, trees, etc., and 

 lick themselves, the hair sometimes coming out 

 and the skin becoming thickened so that mange 

 may be suspected. 



Treatment for lice. — Cattle infested with lice 

 should be dipped in the spring and again in the fall, using a cresol or 

 nicotin dip (see p. 521), or Beaumont oil emulsion (see p. 522). The 

 arsenical dip (see p. 473) is also another remedy which may be effect- 

 ively used against lice. Wlien possible a 

 second dipping should be given after the 

 lapse of 10 to 11 days, and in some cases 

 several treatments may be necessary before 

 the lice are brought under control. The 

 dips mentioned are, as a rule, more effica- 

 cious against lice than lime-sulphur dip. 

 Though lime-sulphur is an excellent mange 

 remedy, it is less .satisfactory for lice, espe- 

 cially blue lice. If only a few cattle are to 

 be treated the dip may be applied with a 

 brush or cloth, or with a small spray pump, 

 or a mixture of kerosene one-half pint and 

 lard 1 pound may be smeared on the body. 



Fig. 12. — Short-nosed 

 blue louse (Ilwma- 

 top inus eury stern us ) 

 of ciittle. Enlarged. 

 ( From Bureau of 

 Entomology.) 



/■f 



Fig. 1.1. — Long - nosed lihio 

 louse (Linoijnathits viiuli) 

 of cattle. Enlarged. (From 

 Bureau of Entomology.) 



MANGE, ITCH, SCAB.* 



Cattle are subject to four kinds of mange, of which common mange 

 or psoroptic mange is the most important. 



1 For a fuller discussion see Farmers' Bulletin 152, issuocl by tlic TTnlted States De- 

 IKirtnii'ut of Agriculture. 



