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



Treatment. — Complete eradication of spinose ear ticks is a difficult 

 matter, on account of the habits and great vitality of the ticks and the 

 wide range of animals which they may infest. Results of investiga- 

 tions conducted by the Bureau of Animal Industry have shown that 

 dipping in any of the known dips or the injection into the ear passages 

 of bland oils, crude petroleum, or various dips, etc., is not effective in 

 killing the ticks or causing them to leave the ears. Gasoline and kero- 

 sene when applied undiluted kill the ticks, but cause blistering of the 

 skin and are not suitable for use on horses. Chloroform, undiluted or 

 mixed with a bland oil. is commonly used on horses and dogs and is 

 effective. Such substances as chloroform evaporate rapidly, and there- 

 fore afford no protection against reinfestation. 



The remedy for ear ticks formulated and thoroughly tested by the 

 Bureau of Animal Industry consists of a mixture of two parts by 

 volume of ordinary pine tar and one part by volume of cottonseed oil. 

 In mixing the ingredients add the cottonseed oil to the pine tar and stir 

 until a uniformly smooth mixture is obtained. When necessary the 

 ingredients should be warmed before mixing, so that they will mix 

 readily and flow freely. The mixture remains uniform without sepa- 

 ration 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 treatment 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 restraint, 

 but in treating wild range horses special equipment is necessary. 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-cotton- 

 seed-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 neces- 

 sary to keep the ears free from ticks. One treatment properly applied 

 can be depended on to kill all ticks in the ears and to prevent rein- 

 festation for about 30 days. It should be remembered, 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 ani- 

 mals 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. 



