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



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, 

 preferably in double-walled, closed containers, until it has under- 

 gone 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 Haematopinus asini. 

 The two other species, Tricliodectes pilosus and T. parumpilosus, 

 are biting lice. 



The sucking louse of the horse is easily distinguished from the 

 biting species. It is much larger and has a long, pointed head, 

 whereas the biting lice have short, blunt, rounded heads. (Figs. 24 

 and 25. 6 ) The sucking louse apparently causes more damage than 

 the biting lice and it is more difficult to eradicate. 



NATURE AND HABITS 



The eggs or nits of the sucking louse are attached firmly to the 

 hairs, usually close to the skin, and they hatch on the. animal in 

 from 11 to 20 days, the majority hatching in from 12 to 14 days. 

 The young lice reach maturity and the females begin laying eggs 

 when they are 11 or 12 days old. The lice pass their lives on horses, 

 and can live only about 2 or 3 days when oft a host animal. 



The biting lice of horses deposit their eggs in the same general 

 manner as the sucking louse. The period of incubation is probably 

 from 8 to 10 days. These lice may live as long as 10 days when 

 separated from the host animal if kept on tufts of hair, but most 

 of them die in 5 or 6 days. 



3 By Marion Imes. 



6 From photomicrographs by W. T. Huffman, of the Bureau of Animal Industry. 



