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



they are put on pasture. Removal of manure from the paddocks, at 

 least once a week, will cut down the supply of eggs and larvae to which 

 the foals would otherwise be exposed, this precaution will help to 

 tide the foals over the most critical period of their lives. 



Young annuals require special care much the same as children. 

 Above everything else, a wholesome food supply and clean surround- 

 ings are the best safeguards against disease. Special precautions to 

 prevent foals from becoming parasitized are essential parts of sound 

 management in horse-breeding establishments and on the average farm. 



THE SMALL STKOZsGYLES 



In addition to the blood strongyles or palisade worms, horses are 

 commonly infested with numerous closely related species of stron- 

 gyles, which are much smaller in most cases than blood strongyles. 

 though some are almost as large. (Fig. 18.) These worms occur 



Figure 19. — Lesions produced by one of the smaller horse strongyles : A, enlarged 

 view of lesion with worms. Triodontophorus tenuicollis, surrounding it; B, types 

 of lesions. (From Ransom and Hadwen. 1918) 



in the colon and cecum and some of them produce visible injuries. 

 One species, Triodontophorus tenuicollis* produces rather severe 

 ulcers in the wall of the colon (fig. 19). probably by means of the 

 sharp teeth in their mouth cups. Some of the smaller horse stron- 

 gyles, the many species known as cylicostomes, species of Trichonema 

 or Cylicostommn. are usually about a half inch or less in length and 

 grayish white in color, and occur attached to the gut wall or free in 

 the contents of the large intestine of the horse. These worms do not 

 feed on blood, at least ordinarily, but they may feed on the mucosa 

 of the large intestine. The immature forms of some cylicostomes 

 occur in nodules in the wall of the large intestine. 



The small strongyles of the horse contribute to the picture of gross 



