24 



CIRCULAR 148, U. S. DEPARTMENT OF AGRICULTURE 



on weight, regain their working capacity, and make an all-round 

 improvement. 



Treatment. — "The drug commonly used for the removal of large 

 strongyles is oil of chenopodium. It is very effective and usually safe, 

 but horses are sometimes slow to recover from the after effects of the 

 medication. When this drug is used, the animal should be fasted for 

 24 to 36 hours before treatment and the drug should be given in a dose 

 of from 4 to 5 fluid drams (16 to 20 cubic centimeters) for a 1,000- 

 pound animal, or at a dose rate of 1 fluid dram (4 cubic centimeters) for 

 each 250 pounds of weight, immediately preceded or followed by 1 

 quart of raw linseed oil or by an aloes ball. Cases of excessive purga- 

 tion have been re- 

 ported in some in- 

 stances following the 

 use of raw linseed oil. 

 It is possible that this 

 undesirable action is 

 clue to impurities in 

 the product ; conse- 

 quently a good grade 

 of oil should be used. 

 A mixture, said to be 

 without the undesir- 

 able effects of raw 

 linseed oil, has been 

 recommended as fol- 

 lows : For wean- 

 lings, castor oil, 4 to 

 6 ounces, and neu- 

 tral oil, 1 pint; for 

 yearlings and 2-year- 

 olds, castor oil, 6 to 

 8 ounces, and neutral 

 oil. 1 pint; for 3- 

 year-olds and older, 

 castor oil, 8 to 10 ounces, and neutral oil. iy 2 pints. 



Carbon tetrachloride also is of value for the removal of large 

 strongyles and is safer than oil of chenopodium for treating pregnant 

 mares. The dose is 6 to 12 fluid drams (25 to 50 cubic centimeters) 

 for a 1,000-pound animal. Normal butylidene chloride is also effec- 

 tive. It is administered after a preliminary fast at a dose rate of 

 3 fluid ounces (90 cubic centimeters) for a 1,000-pound animal, and 

 followed in 5 hours by 1 quart of raw linseed oil. A closely related 

 chemical, normal butyl chloride, is equally effective and is less expen- 

 sive but has the disadvantage of being metabolized into a very un- 

 pleasant smelling substance. This drug is used at a dose rate of 

 approximately 3 fluid ounces (90 cubic centimeters) for a 1,000-pound 

 animal and is administered in from 8 to 10 times its volume of raw 

 linseed oil. 



Recently, a new drug, phenothiazine, has come into wide use as an 

 equine anthelmintic. This chemical is very effective for the removal 

 of large strongyles and some excellent results have been reported 





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Figure 17. — Horse suffering from gross infestation with 

 parasites (strongylidosis). Note marked emaciation. 

 Following treatment for the removal of parasites, this 

 horse made a good recovery 



