48 CIRCULAR 14 8, U. S. DEPARTMENT OF AGRICULTURE 



and stir until a uniformly smooth mixture is obtained. When neces- 

 sary the ingredients should be warmed before mixing,' so that they 

 will mix readily and flow freely. The mixture remains uniform 

 without separation or deterioration, and may safely be used on any 

 species of domesticated animal. Being of a sticky consistence, it 

 remains in the ears and affords protection against reinfestation from 

 30 to 60 days. The only known effective method of applying treat- 

 ment is to inject the remedy into the ear passages by hand.. 



Most horses oppose the insertion of anything into their ears, and 

 some form of restraint is necessary. Gentle farm horses can usually 

 be controlled with the twitch or other well-known methods of re- 

 straint, but in treating wild range horses special equipment is neces- 

 sary. An ordinary crowding chute not more than 3 feet wide is 

 suitable for treating horses for ear ticks. 



An ordinary metal or hard-rubber syringe holding from 1 to 2 

 ounces is the best instrument to use for injecting the pine-tar-cot- 

 tonseed-oil mixture. Have the mixture warm enough to flow freely, 

 fill the syringe, grasp the ear with the left hand, then insert the 

 nozzle into the opening of the ear canal and inject about one-half 

 ounce of the fluid. Hold the ear in an upright position for a few 

 seconds and manipulate to force the mixture into the deeper parts. 

 If too much fluid is injected it will overflow and run down over the 

 head and face, where it may cause blistering. The mixture causes 

 very little irritation except on parts exposed to the direct rays of 

 the sun. 



When the ear passages contain masses of hard wax and ticks, 

 such masses should be broken down and scraped out with a wire loop 

 before treatment is applied. Treatment should be applied as 

 often as necessary to keep the ears free from ticks. One treat- 

 ment properly applied can be depended on to kill all ticks in the ears 

 and to prevent reinfestation for about 30 days. It should be re- 

 membered, however, that the eggs of the tick are not deposited or 

 hatched in the ears of animals, and a new crop of seed ticks may 

 find lodgment at any time on animals kept in infested places. 



TREATING HORSES FOR EXTERNAL PARASITES 



The three commonly used methods of treating horses, mules, and 

 asses for external parasites are (1) hand applications, (2) spraying, 

 and (3) dipping. A fourth method, not in common use but recom- 

 mended by some European investigators, is fumigation with sulphur 

 dioxide. 



HAND APPLICATIONS 



Infested animals may have parasites on any or all parts of the 

 body surface, and to effect complete eradication usually it is neces- 

 sary to cover the entire surface of the skin with the medicament. 

 On account of the difficulty of applying treatment by hand over 

 the entire body surface, hand applications are recommended only 

 as a temporary measure for holding parasites in check until the ani- 

 mals can be dipped or sprayed. 



SPRAYING 



Common parasites on or in the skin can be eradicated by proper 

 spraying, but the method commonly practiced is not economical. 



