CHAPTER VI 



THE PROTOZOA OF THE ALIMENTARY TRACT OF 

 DOMESTIC RUMINANTS AND THE HORSE 



By 

 Elery R. Becker and T. S. Hsiung 



Iowa State College 



Cattle, sheep, goats, and horses are, with the exception of the 

 pig. our most useful domestic mammals. It would seem that our 

 knowledge of the protozoa which may reside in the alimentary 

 tract of these beasts would be more extensive than that of any 

 other animal except man himself, but such is probably not the 

 case. We hazard the guess that more work has been done on 

 the intestinal protozoa of the rat or the frog than on those of 

 any domestic animal. Interest in the latter, however, is developing 

 very rapidly at the present time. 



The first to make any extensive microscopical investigation of 

 the alimentary tracts of domestic animals were Gruby and Dela- 

 fond (1843), who reported in a very general way upon the pro- 

 tozoa which they had observed in ruminants, horses, dogs, and 

 pigs.^ Some of their descriptions are recognizable today ; others 

 are not. Their observations entitle them to the distinction of being 

 called "Fathers of \'eterinary Protozoology," for any general 

 account of the protozoa of domestic animals must necessarily be- 

 gin with them. They are credited with being the first to observe 

 the important protozoan faunas of the rumen and reticulum of 

 ruminants and the large intestine of the horse. 



PROTOZOA OF RUMINANTS 



The 7'itmen (paunch) and reticuliun (honeycomb) of the rumi- 

 nant stomach are esophageal derivatives and as such contain no 



^ It is said that Leeuwenhoek had previously seen certain protozoa from 

 fowls. 



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