16 



CIRCULAR 148, U. S. DEPARTMENT OP AGRICULTURE 



from 6 to 12 fluid drams (25 to 50 cubic centimeters) for a 1,000- 

 pound animal. This drug does not need to be accompanied with a 

 purgative, but it is usually advisable to give purgatives, in this case 

 salts, with carbon tetrachloride for removing worms. 



Prevention. — Prevention of ascarid infestation requires special 

 care of foals and young horses. The time to begin is before the foal 

 is born. The foaling barn should be of sanitary construction and 

 should be cleaned and washed with hot water and lye before the 

 pregnant mare is placed in it. The mare and foal should be kept 

 in a clean paddock, adjoining the barn. It is best to use a paddock 

 from which other horses have been absent for at least a year, and 

 preferably longer. The stable and paddock in which the mare and 



foal are kept should 



be cleaned often, 

 daily if possible, lit- 

 ter and manure being 

 removed. 



These precautions 

 are designed to pre- 

 vent the foals from 

 becoming heavily in- 

 fested with ascarids 

 at an early age, and 

 before they have de- 

 veloped the necessary 

 reserve vitality to 

 cope s u c c e s sf ully 

 with a heavy worm 

 infestation. When 

 the foal is moved to 

 a pasture it is essen- 

 tial to select one 

 which is clean and 

 that has not been 

 used by horses for a 

 year or longer. 

 Horses may be 

 moved to cow and 

 sheep pastures and 

 vice versa, because 

 parasites of rumi- 

 nants are not transmissible to horses, and equine parasites are not 

 transmissible to cattle and sheep, as a rule. Proper disposal of 

 manure, and sanitary measures recommended in connection with the 

 control of blood strongyles will also help to prevent infestation with 

 ascarids. 



While infestations with ascarids can be acquired on pastures, and 

 often are so acquired, it is important to remember that ill-kept 

 stables, in which manure is allowed to accumulate (fig. 9), are also 

 the sources of heavy infestations with intestinal roundworms, pin- 

 worms, and other threadworms. Under pasture conditions many 

 eggs and larva? succumb to drought and to other unfavorable in- 

 fluences which prevail in the open. In manure-laden stalls parasite 





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Figure 9. 



-Type of insanitary box stall. Note accumu- 

 lation of litter and manure 



