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



worm infestations in horses trace back to manure as the original source. 



Manure must be regarded as dangerous, and control measures should 

 be designed to prevent contaminating the feed and water with manure 

 so far as it is possible to do so. The following measures are designed 

 to reduce the possibilities of gross infestations of horses with parasites : 



Pastures should be stocked lightly. Heavy stocking means more 

 manure, and this, in turn, means a heavier concentration of parasite 

 eggs and larvae. 



Sloping hillside pastures are better than level ones. Rain and 

 melting snow tend to wash manure down to some extent from sloping 

 pastures. The bottom of a sloping pasture is dangerous because it has 

 a high concentration of eggs and larvae. It should be fenced off if 

 possible. 



Rotation of pastures is desirable and should be used so far as avail- 

 able pastures permit. It is important to remember that permanent 

 pastures perpetuate parasites. 



Stock rotation is a sound procedure. For the most part the parasites 

 of cattle, sheep, and goats are not transmissible to horses, and vice 

 versa. Move horses to a pasture on which cattle or sheep have been 

 grazing and move cattle and sheep to a horse pasture in alternate years. 



Keep stables clean ; remove manure often, daily if possible ; supply 

 clean bedding and change it often ; and supply clean water. 



Feed from boxes well raised above the ground and from overhead 

 racks. Do not feed from the ground, because the feed will become 

 contaminated with manure. 



Do not spread fresh manure on pastures. Hold stable manure, pref- 

 erably in double-walled, closed containers, until it has undergone a 

 heating process. If you have an open manure pile, turn the outer few 

 inches of the manure once a week. Bury it under the inner portion. If 

 you have no facilities for keeping manure, haul it to areas used by 

 animals other than those that produced the manure or plow it in for 

 field crops. 



Take steps to reduce the fly nuisance by storing manure in closed 

 containers or use flytraps or other preventive measures recommended 

 by the United States Department of Agriculture. 



Remember that foals require special treatment to tide them over 

 the critical period of infancy. If you expect to raise sound horses, 

 protect the foals. 



Consult a veterinarian when your horses require medicinal treat- 

 ment for the removal of parasites. 



EXTERNAL PARASITES OF HORSES 5 



HORSE LICE 



Usually lice are restricted to one host species or to closely related 

 species, and horse lice will not live on animals other than horses, 

 mules, and asses. Three kinds of lice are commonly found on horses 

 in the United States. The first and most important of these is the 

 blood-sucking species known technically as Haematopinm asini. The 

 two other species, Trichodectes pilosus and T. parwwpilosus, are 

 biting lice. 



5 By Marion Imes. 



