Stomach Worms in Sheep. 9 
before they are taken up by the lambs. There is but very slight 
danger that young lambs will become affected seriously while running 
with older sheep in barns or yards free from vegetation. Early lamb- 
ing, combined with good feeding of the ewes to make them milk well, 
or of the lambs themselves in a “‘creep,” or with both, brings early 
lambs to marketable weight and finish before the most dangerous 
part of the summer. Where lambs must remain for several months 
on pasture, frequent changing of pasture must be resorted to, to 
keep infestation below the extent that is injurious. 
A PRACTICABLE METHOD OF PASTURE ROTATION, 
The means of preventing the stomach-worm larve from getting 
into the lambs is suggested by what has been said concerning its 
development and powers of resistance. It was stated that a pasture 
that had been occupied by wormy sheep would need to be for at 
least a year without cattle, sheep, or goats in order to become 
practically free from [aeesteweres larve. 
_ From 10 to 20 days, according to temperature and moisture, must 
intervene between the droppmeg of the feces containing stomach- 
worm eggs and the development of many of the larve to a point 
where they will develop into adult worms after being swallowed. If 
sheep are moved to a fresh pasture before the eggs in their droppings 
develop into mature larve, complete health can be maintained. The 
practical difficulty les in always having a fresh pasture available. 
If only permanent grass pasture were used, adequate control would 
call for as many separate pastures as would allow the flock to be 
moved at least every 2 weeks without going on the same ground 
twice withm 12 months. The time of grazing during freezing 
weather would not be included in such a plan, as few of the eggs or 
young larve would survive. It should be observed that it is not 
simply the changing of pastures that is called for, but changing to 
clean ground. Putting infested sheep on pasture in May, removing 
them during June and returning them in July, offers an excellent 
chance for infestation from the eggs dropped during the first pastur- 
ing which would have hatched out into young worms waiting to be 
taken up. 
Some modifications of such a plan are quite practicable on any 
farm. In the first place, the danger is greatest to the lambs, and after 
they are sold or separated the ewes may go back to pastures used 
earlier in the season with much less danger of injury than would be 
incurred by the lambs. This change, however, would render that 
_ pasture unsafe for young lambs during the following spring. Hay- 
fields, grain stubble, and cornfields can be utilized in the rotation of 
fields to furnish fresh grazing. 
