512 



DISEASES OF CATTLE. 



Fig. 7.— Short-nosed blue 

 louse (HxTnatopinus eu- 

 rysternus) oicnttle. En- 

 larged. (From Bureau 

 of Entomology.) 



The blue lice (figs. 7 and 8) suck the blood of cattle and are more 



injurious than the red lice (fig. 9). 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. 10) which they fasten to the hair. The blue 

 lice infest chiefly the neck and shoulders ; red lice, 

 when present, may be found almost anjrwhere on 

 the body, but are usually most numerous on neck, 

 shoulders, and at the root 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 may be treated for 

 lice by means of hand applications, spraying, 

 or dipping. Dusting powders sold under vari- 

 ous trade names are of value in helping to hold lice in check 

 when the weather is too cold for dipping or spraying. {^The applica- 

 tion of greases and insecticidal liquids by hand is fairly effective and 

 practicable in cases in which there are only a few animals to be treated. 

 The following remedies have proved effective 

 when applied by hand, the treatment being 

 repeated if necessary in about 16 days: (1) 

 Cottonseed oil and kerosene, equal parts; 

 (2) kerosene, ^ pint, mixed with lard, 1 

 pound; (3) crude petroleum; (4) any of the 

 dips recommended for use in dipping, and 

 diluted in the same proportions as for dip- 

 ping. Oils or greases should not be used 

 in very warm or very cold weather. \The 

 remedies mentioned may be applied with 

 a brush or a cloth.) They should be dis 

 tributed in a thin, even coating over the 

 surface of the body, taking care that there 

 is no excess quantity at any point. 



In spraying, any of the dips recommended for lice, properly 

 diluted, are applied by means of a spray pump over the entire body. 

 Thorough wetting of the skin and hair is important, and a second 

 treatment should be given 15 or 16 days later. 



When a considerable number of animals are to be treated the most 

 satisfactory method of destroying lice is by the use of a dipping vat. 



FiG.8.— Long-nosed bluelouso (itno- 

 gnathus vituli) of cattle. Enlarged. 

 (From Bureau of Entomology.) 



