536 DISEASES OF CATTLE. 



Of these may be meiitioiiotl the liook worm (BunostomuTn phlehoto- 

 mum) .and the nodular worm {(Esophagostomiim radiatum). The 

 former is about an inch long and is foimd in the small intestine. The 

 latter are somewhat smaller and are found in the cecum and large 

 intestine. Plook Avorms, when numerous, may cause anemia and 

 other symptoms similar to those caused by stomach worms (see p. 

 530.) The injury to the mucous lining of the intestine from the bites 

 of hook worms may cause severe inflannnation. 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 nourishment from the intestinal contents. Several species of 

 small, very slender roundworms {Trichostrongyhts) , less than a 

 quarter of an inch in length, sometimes occur in the small intestine 

 and fourth stomach, and a severe gastro-enteritis, or inflamnuition of 

 the stomach and intestines, has been attributed to them. 



Xodiilar disease of the intestine, due to young nodular worms 

 which burrow in the intestinal wall during a certain stage in their 

 life history, though sometimes apparently producing serious effects, 

 particularly in young cattle, usually has little or no perceptible influ- 

 ence on the general health. Nodular disease, however, often renders 

 the intestine unfit for use as sausage casings, and as it is widely prev- 

 alent among cattle, the loss from this source is considerable. The 

 greenish or yellowish 'nodules with cheesy contents are frequently 

 mistaken by the inexperienced for lesions of tuberculosis. 



The life histories of the various small roundworms occurring in 

 the intestines of cattle have not been worked out, but in general they 

 are very likely similar to that of the twisted stomach worm as de- 

 scribed on page 530. 



Treatment for intestinal roundworms. — The preventive measures 

 are similar to those reconnnended in the case ot the twisted stomach 

 worm (p. 533). Medicinal treatment is generally not very satisfac- 

 tory. Powdered thymol, in doses of 200 grains or more, has been 

 recommended, but it often fails to have the desired result. It is 

 claimed by one author that 2 or 3 drams of rectified empyreumatic 

 oil in a mucilaginous emulsion, followed the next morning with a 

 I)urgative of 1 to 1^ pounds of sulphate of soda, will expel the large 

 roundworms {Ascaris vitidorum). 



Protozoa. 



A number of species of protozoa have been reported as parasites of 

 the intestines of cattle. To one species has been attributed a serious 

 disease of cattle in Switzerland known as red dysentery, but as yet 

 no cases of this disease in American cattle have been reported. 



