20 FARMERS' BULLETIN 840. 



make further growth for later use. Cowpeas are good for the older 

 sheep, though unpalatable to lambs. Bermuda grass, when kept 

 short, is especially good when reinforced by lespedeza and bur 

 clover, which grow at different seasons from the Bermuda grass and 

 here find their best use as a sheep pasture. The aftermath of grain 

 and timothy fields furnishes feed for many flocks and helps greatly 

 to bring down the cost of carrying the flock through the summer. 



AVOIDING STOMACH WORMS. 



In many farming sections the flockmasters most serious troubles 

 are likely to be caused by internal parasites, the effects of which are 

 particularly evident during the later part of the pasture season. 

 Of these parasites the stomach worm is the most common and trou- 

 blesome. It occurs wherever climatic conditions and methods of 

 keeping the flock are favorable for its development, which means 

 on most farms, and probably all. No practicable means of entirely 

 avoiding infection with this parasite has been discovered, but by 

 proper arrangement of the summer pasturage it is possible to keep 

 the numbers of the worms below the danger point. A knowledge of 

 the development of this parasite affords a basis for the changing of 

 pastures that insures a healthy condition of the flock. 



The stomach worms live in the fourth stomach. 1 They are from 

 one-half to 1J inches long and have a fine red stripe running in 

 spirals from end to end of the body. Their eggs pass out in the 

 droppings of the sheep and hatch in a few hours, days, or weeks, 

 according as the temperature is high or low. At temperatures lower 

 than about 40 F. development is arrested. The larva which hatches 

 from the egg crawls up on the grass blades when they are moist, 

 and after attaching itself to the blade may be swallowed by some 

 animal. The eggs are frequently killed by freezing or drying, but 

 the larvae will sometimes live for months and can withstand re- 

 peated freezings. After being taken into the body of a ruminating 

 animal they develop into the mature worms. Cattle and goats also 

 act as hosts to these worms but usually are not so seriously affected 

 as sheep. 



The injurious action of stomach worms may be attributed to two 

 things : First, the loss of blood extracted by the parasites and the loss 

 of nutritive materials which may be absorbed by them from the ali- 

 mentary fluids; and, second, the destruction of red corpuscles by a 

 poisonous substance secreted by the parasites which is absorbed into 

 the blood. Lambs that are affected become pale, thin, and weak 

 and may either die or continue for a long time in poor condition and 

 fail to grow as they should. The absorption of blood from the lambs 



1 The information here given with regard to stomach worms is mostly taken from 

 Bureau of Animal Industry Circular 157, written by B. II. Ransom. 



