SEVENTH AISNUAL YEAR BOOK— PART X. 497 



1. It is assumed that a large pasture is available which has had no 

 sheep, goats, or cattle upon it for a year, if a permanent pasture, or since 

 cultivation, if a seeded pasture. This pasture is subdivided into two by a 

 double line of fence, and a drainage ditch is run along the alley between 

 the two fences. At one end of the alley between the two subdivisions a 

 small yard is constructed, communicating with each of the subdivisions by 

 means of a gate. When the lambs are born they are placed in one of the 

 subdivisions and the ewes are placed in the other. The small yard should 

 be kept free of vegetation and must not drain into the lamb pasture. As 

 often as necessary the lambs are allowed in the small yard with the ewes 

 for suckling. The rest of the time the lambs and ewes are kept separate 

 in their respective pastures. By this arrangement the lambs are exposed 

 to infection only while they are in the small yard, where they may be- 

 come infected either by embryos of the stomach worm present on the ma- 

 nure-soiled skin of the infested ewes, or by embryos picked up from the 

 ground which has been contaminated by the droppings of the ewes. The 

 chances of infection from the skin of the ewe are so slight that in practice 

 this source of infection need not be considered. The danger of infection 

 from the ground may be avoided by frequently removing the manure from 

 the yard and keeping the surface sprinkled with lime and salt. The lambs 

 and ewes will soon learn the way to their proper pastures, and after a 

 few days little difHculty will be experienced in separating them each time 

 after the lambs are through suckling. 



2. Another plan which may be followed where the climatic conditions 

 are suitable — that is, in regions where there is a cold winter season — is 

 that of having the lambs born at a time of year when there will be no 

 danger of their becoming infected during the suckling period, and wean- 

 ing and separating them from the rest of the flock before the advent of 

 warm weather. Under the usual climatic conditions of the state of 

 Ohio, for instance, if the lambs are born in the latter part of October 

 or the first of November they may remain with the ewes on fields which 

 have not been previously occupied by sheep, goats or cattle within a year 

 — or, if cultivated fields, since cultivation — until the following March with- 

 out danger of becoming infected, since the eggs in the droppings of the in- 

 fested ewes will not hatch out during this time of year because of the 

 cold weather. The use of fields not previously occupied by sheep, goats, or 

 cattle within a year, or since cultivation, is necessary, since otherwise the 

 fields would be already infected with young worms which had hatched out 

 and reached the infectious stage before the beginning of cold weather, 

 and the lambs would consequently be liable to infection from picking up 

 these young worms, which are not killed by cold weather after they have 

 reached the final stage of larval development. When they are weaned 

 the lambs must, of course, be placed on clean pasture, if they are to con- 

 tinue free from infection. With this method only two clean pastures are 

 necessary, one in which the ewes and lambs are placed in the fall, and 

 another for the lambs when they are weaned in March. 



Unfortunately for this scheme. It is not always possible to have lambs 



born at the beginning of the winter seaspn; but with additional clean 



pastures a modification of the foregoing method may be used in the case 



of lambs born toward the end of the winter or in the spring. In the 



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