worm, and perhaps the state in the intestinal mucosa is entirely omit- 

 ted at times. Curtice (1890c) made observations, and surmises that 

 this species develops normally in the lumen of the intestines, and even 

 gets to the mesenteric glands, the liver or the omentum ; that those 

 which penetrate the wall of the intestines may develop slowly and at 

 length get to the lumen of the intestines, or may die ; that this tumor- 

 making stage of the life history may favor the survival of the species 

 by providing slowly developing forms which pass the winter here 

 and mature in the spring, at a time when the eggs spread on the pas- 

 tures will better serve the purpose of infestation; and that worms 

 penetrating the walls of the intestines too deeply, such as those attain- 

 ing the omentum or the liver, perish/' 34 



This disease is incurable, and animals infested must be properly 

 managed. If not intelligently managed the entire breeding flock will 

 be lost eventually Symptoms of the disease in lambs are diarrhoea, 

 vigorous appetite, loss in condition of flesh and enfeebled thrift. 

 This disease is more fatal to mature sheep than to lambs because of 

 time required for the disease to develop to an acute stage. In mature 

 sheep the disease is recognized by an emaciated condition, feeble- 

 ness, pale or bluish skin, a listless expression of the eye, and a good 

 appetite. The vitality is lowered, and the extra strain of lambing, 

 secretion of milk and exposure to weather cause complication and 

 death. Some ewes while apparently in high condition of flesh, are 

 noticeably lacking in vigor. 



Rotation of Pastures. 



In order to control parasites, rotation of pastures for the flock is 

 considered the most practicable method. Another method is the in- 

 tensified forage crop system used by English shepherds on high-priced 

 land. 



By having the pasture so arranged as to allow the flock to be 

 alternated every ten days on two or more areas, the infestation of the 

 sheep by the worms can be partially controlled; for during the 

 interval that the sheep are off pasture many of the larvae that are 

 developed in the feces from the sheep die. In a badly infested flock 

 the 4ambs should be weaned prior to June, or kept in dry lot separate 

 from the ewes, and allowed to nurse their mothers at night. Lambs 

 raised in dry lot for breeding purposes, when fed succulent feed in 

 the form of green alfalfa, clover and other forage crops, with grain, 



84 Twenty-seventh Annual Report, Bureau of An. Industry, U. S., page 448. 



28 





