Common Parasites 



17 



ers, and are to be found in the last division of the stomach (abom- 



asum) of cattle, sheep and 

 goats. 



Symptoms. Diarrhoea, ir- 

 regular appetite, paleness of 

 the visible membrane and 

 water swelling under the chin 

 and lower jaw, (Poverty jaw), 

 are the common symptoms. 



In sheep the skin becomes 

 dry and harsh and the con- 

 dition is sometimes known as 

 "paper skin." 



Losses are caused by the 

 debilitated condition due to 

 the continual loss of blood. 

 Young animals suffer more 

 severely than adults and the 

 proportion of deaths among 

 them is greater. 



Life History. The eggs of 

 the worm are passed out with 

 the manure and hatch on the 

 ground. The larvae, minute 

 worms, crawl upon the grass 

 and other vegetation. During 

 FIG. 54. The stomach worm tffemonchu* con- warm moigt weather in 

 tortus). Enlarged. * Vulva. (From Bu- 

 reau of Animal Industry Bulletin 127.) swampy areas m the pastures 



the larvae are very active and may live several weeks outside the 

 body of an animal. During cold or very dry weather they cannot 

 live as long as in warm, moist weather. During dry weather they 

 may be found coiled upon the surface of grass blades and the leaves 

 of plants. Cattle grazing on pasturage infested with the parasites 

 become infested through consuming the grass. Upon reaching the 

 stomach the larvae begin to grow and reach maturity in two to four 

 weeks. 



Treatment and Prevention. Prevention consists in drainage of 

 all swampy areas in pasture and frequent rotation of pasture. Every 

 farm should have a sufficient number of pastures so that each pas- 

 ture may be left free of animals for two months twice a year or 

 oftener in order to give opportunity for parasites infesting the soil 

 or herbage to die off, as they will do if animals are kept away for 

 a sufficient length of time. Burning over the pastures also serves 

 to keep down parasitic infestations. The water supply should be 

 be from well or spring or freely flowing stream. Animals must not 

 be permitted to drink stagnant water at any time. A plentiful 



