ANIMAL PARASITES OF CATTLE. 



513 



(Two dippings should be given 15 or 16 days apart. Dipping in the 

 fall is good insurance against risk of loss from lice during the winter. 

 All animals in the herd should be treated regardless of the number 

 showing infestation. C Either^coal-tar-creosote 

 or nicotin dips may be used^- These are sold 

 under various trade names. The directions 

 for dilution given by the manufacturer should 

 be carefully followed. As coal-tar-creosote 

 dips do not mix well with all kinds of water, 

 they should be tested wdth the water to be 

 used for making the solution by mixing some 

 of the dip in the proper proportions with the 

 water in a clean and clear-glass bottle or jar. 

 If an oily layer or mass of globules collects 

 either at the top or the bottom of the mix- 

 ture after standing an hour, the dip is not 

 suitable for use with that kind of water. 

 Imperfectly mixed coal-tar-creosote dips are 

 liable to poison animals even when not used 

 in stronger solutions than that recommended 

 b}^ the manufacturers, and are also likely to 

 be inefficacious. 



The lime-sulphur dip, which is highly effica- 

 cious as a mange remedy, is of little value for destroying lice, espe- 

 cially blue lice. The arsenical dip used in tick eradication is a good 

 louse remedy, but its use is not advisable on account of its poisonous 

 nature, except under the supervision of capa- 

 ble persons who know how to use it and what 

 precautions to take. 



MANGE, ITCH, SCAB.i 



Cattle are subject to four kinds of mange, 

 of which common mange or psoroptic mange 

 is the most important. 



PSOROPTIC MANGE. 



Fig. 9.— Red louse ( Trichodectes 

 scalaris) of cattle. Enlarged. 

 (From Bureau of Entomology.) 



Fig. 10.— Egg of short-nosed blue 

 louse {Hsematopinus euryster- 

 nus) attached to a hair. En- 

 larged. (From Bureau of En- 

 tomology.) 



Psoroptic mange of cattle is caused by small 

 mites (fig. 11) 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. The mites attack the skin and 

 cause it to become thickened and covered with crusts and scabs, with 

 a consequent loss of hair. Intense itching accompanies the disease, 



1 For a fuller discussion see Farmers' Bulletin 1017, issued oy the U. S. Department of Agriculture. 

 54793°— 23 33 



