10 Department Circular 47, U.S. Department of Agriculture. 
Plowing the land infested with the larve of stomach worms greatly 
reduces the danger of infection. This fact allows the same land to be 
used two or three times for sheep in a season by using forage crops. 
Fall-sown wheat can be used for the earliest period, the land broken 
and resown to peas and oats, rape, or soy beans for a later grazing, 
and in some cases plowed again and sown to wheat to furnish late-fall 
feed. A succession of such crops is particularly desirable for carrying 
over from weaning time until winter the ewe lambs that are to be 
retained in the flock. | 
Where sufficient changes of pasture and fresh ground can not be 
provided, preventive dosing may be partially relied upon. The 
danger in depending upon treatment lies in the fact. that while cures 
usually can be effected by its proper use, lambs that have been al- 
lowed to reach the point where medicine is needed have at least been 
seriously checked in growth, and unless very carefully watched some 
deaths will occur. 
The treatment can be used as a measure to hold the stomach 
worms in check, in conjunction with rotation of pastures. Many 
successful shepherds dose all the ewes before turning them on the 
spring pastures with the lambs. This greatly lessens the number of 
eges dropped. Afterwards all the lambs to be kept are similarly 
treated at the time of weaning, and individual cases may be treated 
on the first appearance of symptoms which will be noted if the flock 
receives the attention it really requires. When pasture rotation and 
similar preventive measures are impossible, sheep may be given the 
copper-sulphate treatment, preferably in diminished dosage, every 
month or 6 weeks during the summer season. 
The stomach worm need not be a serious trouble for a good shep- 
herd who has his lambs come early, feeds well, drenches the flock as a 
measure of prevention, and provides a rotation of pastures or pasture 
crops. 
