48 PARASITES OF THE DOMESTIC ANIMALS 



habit of bringing forth its young adapting it to spend its whole life upon 

 the host from which it never migrates imless to attach to another animal 

 of the same species. It is probable that this migration occurs principally 

 at the time of shearing when the ticks leave the sheared sheep and crawl 

 upon the lambs. Off the host the ticks will not survive longer than a 

 few days, probably all will be dead within a week. 



Effect. — All breeds of sheep are alike subject to attack, the presence 

 of the "tick," or "louse," as it is commonly called, and the injury which 

 it causes, being a matter of common Icnowledge to sheep breeders. Sheep 

 are not materially affected by a few, but if in larger numbers, their 

 presence will be manifested by rubbing, scratching, and biting at the 

 fleece. Loss of flesh and general unthriftiness will occur in badly in- 

 fested animals. Where the ticks are prevalent lambs may be attacked 

 by large numbers at shearing time, in which condition many will die 

 unless promptly relieved.' 



Treatment. — In the winter months, when the long wool will not 

 permit of other treatment, the ticks may be greatly reduced in number 

 by the use of pyrethrum powder which should be freely blown deep into 

 and upon the fleece over all parts of the body. The most effectual treat- 

 ment is best applied after shearing and consists of the application by 

 dipping or as a wash of such remedies as creolin, zenolium, lysol, or 

 cresol, used in two to three per cent, strength. Decoction of tobacco, 

 in strength of three to four per cent, is also used, but, to avoid danger of 

 nicotine poisoning, should not be applied to all parts of the body at once. 

 Kerosene emulsion, which has a wide range of usefulness in the treat- 

 ment of external parasites, is another of the numerous dips resorted to 

 in this connection. The emulsion may be made either with milk or soap 

 according to the following formulae : 



Milk emulsion. — To one part milk add two parts kerosene and churn 

 by a force pump or by other means of agitation. Dilute the resulting 

 emulsion with eight to ten times its bulk of water. 



Soap emulsion. — Dissolve one-half a poimd of hard soap in one gallon 

 of hot water and, while still at near boiling point, add two gallons of 

 kerosene. Emulsify by use of force pump or other means of agitation. 

 Dilute one part emulsion with eight or ten parts water. 



These emulsions may be used in the proportions given as a spray, 

 wash, or dip. 



None of these dips will kill the pupae, and, therefore, keeping in 

 mind the life history of the parasite, the treatment should be re- 

 peated in about twenty-four days. If the dipping has been done in 

 the cooler weather of autumn, this interval should be accordingly 

 prolonged. 



As the movement of the ticks from the sheep to the lambs takes place 

 principally at the time of shearing when the insects are removed from 



