532 



DISEASES OF CATTLE. 



but finally becomes contiijuous. The disease lasts from two to five months, 

 wlieii the most extreme cases sui-cumli. 



Most of the German cattle are said to be infeslcil with liver flukes, but even 

 when a large number are ijreseiit the nourishment of the cattle is not dis- 

 turbed. Thickening of the gall ducts, so that a sn-called "Medusa's head" 

 forms on the surface of the liver toward the stomach, appears in even well- 

 nourished animals ; even in cases of a cirrhosis of the liver it is seldom that 

 any elfect upon the cattle's health can be noticed, and so long as a portion of 

 the liver tissue about twice the size of the fist remains Intact, the nourish- 

 ment of the animal may l)e comparatively good. II is rare that one sees a 

 generalized edema in slaughtered cattle as a result of fluke invasion, and even 

 in the heaviest infections of young cattle only emaciation is noticed. 



Treatment. — Medicinal treatment is unsatisfactory. The disease may be 

 lircvcnted to a coiisidoi-alile extent liy giving animals i)lenty of salt, and by 



introducing carp, frogs, and 

 toads into infected dis- 

 tricts ; these animals de- 

 stroy the young stages of 

 the parasite and feed upon 

 the snails which serve as 

 intermediate hosts. 



The drainage of wet 

 pastures and the avoid- 

 ance of swampy lands 

 for grazing purposes 

 are important measures 

 in tlie prevention of 

 flulce disease.s. 



Eiiilliet and otliers 

 liave recently recom- 

 mended the application 

 of lime to fluky pas- 

 tures, having dis.;o\-ered that very weak solutions are destructive not 

 only to fluke embryos but to snails. This application is to be made 

 (hiring the summer months at the rate of about 500 to 1,000 pounds 

 of lime per acre. The same authors also recommend for the treat- 

 ment of fluke disease extract of male fern in doses of 5 gTams to 

 eacli oO kilogi'am.s of body weight. Apparently, however, satisfac- 

 t(jry results from this treatment are not always obtained. 



TAPEWORM CYSTS OF LIVER AND OTHER VISCERA. 



Three kinds of tajieworm cysts are found in the ^■iscera of cattle. 

 One of these {Mii/th-e/is mult ice ps, or Co'inirus cei-eliralh') will be 

 further referred to in the discussion of gid (p. 533). All these are 

 tlie iiiterniGdiate stages of tapeworms, which live vhen mature in the 

 intestines of dogs, wolves, and other canines. The eggs of the tape- 

 A\orms are scatter(Mi (.>\er tlic fields in the droppings of infested clogs 

 or -woh OS, nnd when swalloved in food or water by cattle hatch out 



ic. i;0. — Portion of ^^rass stalk bearinu- three eneystcd 

 (■(■rcariii? of the common liver fluke ifasciuJa Iwpatlvii} . 

 Knlar;;i-cl- 



