16. CIRCULAR 148, U. 8. DEPARTMENT OF AGRICULTURE 
from 6 to 12 fluid drams (25 to 50 cc) for a 1,000-pound animal. 
This drug usually need not be accompanied with a purgative, but 
it is advisable to give a saline purgative immediately following the 
administration of carbon tetrachloride for the removal of worms, 
particularly ascarids, from colts. 
Prevention.—Prevention of ascarid infestation requires special 
care of foals and young horses. The time to begin is before the foal 
is born. The foaling barn should be of sanitary construction and 
should be cleaned and washed with hot water and lye before the 
pregnant mare is placed in it. The mare and foal should be kept 
in a clean paddock adjoining the barn. It is best to use a paddock 
from which other horses have been absent for at least a year. The 
stable and paddock 
in which the mare 
and foal are kept 
should be cleaned 
daily if possible, lit- 
ter and manure be- 
ing removed. 
These precautions 
are designed to pre- 
vent the foals from 
becoming heavily 
infested with asca- 
rids at an early age, 
and beforethey have 
developed the neces- 
sary reserve vitality 
to cope successfully 
with a heavy worm 
infestation. When 
the foal is moved to 
a. pasture it 1s essen- 
tial to select one 
which is clean and 
that has not been 
used by horses for a 
year or oncer 
Horses may be 
FIGURE ripe al es Leek Sea Note accumu- moved to cow and 
sheep pastures and 
vice versa, because parasites of ruminants are not transmissible to 
horses, and equine parasites are not transmissible to cattle and 
sheep, as a rule. Proper disposal of manure and sanitary meas- 
ures recommended in connection with the control of blood strongyles 
will also help to prevent infestation with ascarids. 
While infestations with ascarids can be acquired on pastures, 
and often are so acquired, it is important to remember that ill-kept 
stables, in which manure is allowed to accumulate (fig. 9), are also 
the sources of heavy infestations with intestinal roundworms, pin- 
worms, and other threadworms. Under pasture conditions many 
eggs and larve succumb to drought and to other unfavorable in- 
fluences which prevail in the open. In manure-laden stalls parasite 
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