DISEASES OF CATTLE 367 



employed. Medicinal treatment is of little use, owing to the pro- 

 tected position in which the parasite occurs. 



INTESTINAL PARASITES. 



TAPEWORMS. 



Two species of tapeworms are known to occur in the small 

 intestine of American cattle. They sometimes grow to a length of 

 several yards and to a breadth of three-fourths of an inch. Small 

 portions of tapeworms, consisting of one or more segments, are 

 occasionally seen in the droppings of infested cattle. The life his- 

 tory is not known, but the infectious stage is undoubtedly taken in 

 with the food or water, infection being spread by the eggs of the 

 parasite contained in the feces of infested animals. The eggs per- 

 haps are swallowed by some small creature (an insect, worm, or 

 snail) which acts as an intermediate host, and which when swal- 

 lowed accidentally by a cow while grazing or drinking carries with 

 it into the cow's stomach the infectious stage of the tapeworm. 



Adult cattle do not seem to suffer much from infestation with 

 tapeworms, but in calves these parasites may cause scouring and 

 emaciation. 



Treatment for Tapeworms. Medical treatment for tapeworms 

 in cattle is usually unsatisfactory, but the bluestone treatment used 

 for stomach worms and mentioned above may be tried. Arsenic 

 in doses of 1^2 to 3 grains has been claimed to give good results in 

 the treatment of calves for tapeworms. 



ROUNDWORMS. 



A large roundworm (Ascaris vitulorum) measuring 6 to 12 

 inches in length sometimes found in the intestine of cattle, espe- 

 cially calves, may cause inflammation and occasionally rupture of 

 the intestine. Infection occurs through the swallowing of the eggs 

 of the parasite in food or water which has been contaminated with 

 the feces of infested cattle. 



A number of species of small roundworms, varying in size from 

 an eighth of an inch to an inch or more in length, occur in the in- 

 testines. Of these may be mentioned the hook worm (Monodon- 

 tus phlebotomus) and the nodular worms (CEsophagostomum col- 

 umbianum and 0. radiatum). The former is about an inch long 

 and is found in the small intestine. The latter are somewhat 

 smaller and are found in the cecum and large intestine. Hook 

 worms, when numerous, may cause anemia and other symptoms 

 similar to those caused by stomach worms. The injury to the mu- 

 cous lining of the intestine from the bites of hook worms may cause 

 severe inflammation, and affords an avenue of infection with the 

 germs of various diseases. The adult nodular worms apparently 

 do not attack the wall of the intestine, but derive their nourish- 

 ment from the intestinal contents. Several species of small, very 

 slender roundworms (Trichostrongylus') , less than a quarter of an 

 inch in length, sometimes occur in the small intestine and fourth 

 stomach, and severe gastro-enteritis, or inflammation of the stom- 

 ach and intestines, has been attributed to them. 



