6 FARMERS' BULLETIN 1341
Some of the common defects in jacks which should be avoided are:
Flat, narrow cliest, which indicates a weak constitution and lack of
vigor; light-muscled loin and long coupling; short, drooping rump;
excessive length of leg; light bone; poor hocks, with a tendency toward
curbiness; small feet with contracted heels; and short or droopy
ears.
CARE OF THE JACK
The proper care and management of the jack are somewhat exacting,
as he is rather peculiar in his likes and dislikes. While a stallion
may be spoiled because of his nervous temperaiielnt, the jack
may be just as quickly ruined because of his inclination to be sluggish.
The jack should have a caretaker who understands jack management
thoroughly. This is very important, as the disposition of
the jack is partly controlled by the groom. The jack should be quietly
but firmly handled. A bad disposition in a jack is usually attributable
to harsh handling or mismanagement of the animal when young.
Through continuous observation the groom should learn the peculiar
individuality of the jack and the little things required for his proper
management.
Abundant exercise is one of the big factors in the management of
a breeding animal. A roomy, well-ventilated, and well-lighted box
stall opening to an exercising paddock is necessary for the proper
care of the jack. It is important that the exercising paddock be of
good size. Moreover, in order to insure plenty of exercise, it is well
to give the jack some road work.
A young jack intended for siring mules should not be permitted to
run with jennets or mules. as this practice usually leads to difficulty
in teaching him to serve mares, when used in the stud. Instead the
young jack should have fillies or gentle mares for companions. The
jack may begin serving mares at the age of 2 or 21/ years. At this
early age he should be bred to only a few mares. When he is 3 years
old he may serve 25 or 30 mares. but he should not be allowed more
than one mating a day. A mature jack may serve as many as two
mares in a single day provided the two services are several hours
apart. The number of mares a jack should serve luring a season
depends on the strength and vigor of the individual, but 70 or 80
mares probably is the maximum number that he can serve with
satisfactory results. Artificial breeding may be employed if the jack
is patronized very heavily. This not only conserves the vitality of
the jack but also enables the owner to breed a much larger number of
mares. If care and precaution are taken, artificial breeding may be
practiced with as much success as breeding in the natural way. In
fact, some mares which do not conceive from natural service are successfully
impregnated artificially. It is sometimes advisable to use
a stallion for teasing purposes in order to conserve the jack when the
patronage is heavy.
FEEDS FOR THE JACK
The jack is a rather sluggish animal, and for this reason his feeds
should be slightly laxative in character. Wheat bran, oats, crushed
barley, and linseed meal are splendid grain feeds to use. Sheaf oats
and green feeds are also very satisfactory. Corn should be used only in
limited quantities and preferably during winter months. Many jack
