Fig. 208.
A fore-hoof showing a Chadwick
spring in proper position:
a, Chadwick spring;
b, ferrule to stiffen
spring as desired; c,
uncompressed spring before it
has been engaged against the
buttresses; d, buttresses
in which points of spring
are buried.
For contracted hoofs of the acute-angled form we use the bar-shoe, and if there are other diseases of the hoof present, or if we wish a more rapid and continuous expansive action, we use also a leather sole with foot-packing with or without a buttress spring. A foul frog should be properly cleansed, and then disinfected with pine-tar thinned with alcohol or crude wood-vinegar (pyroligneous acid).
Further curative measures are: turning the horse out without shoes (expensive and seldom practicable); applying tips; using shoes the bearing-surface of whose branches inclines downward and outward (unilateral contraction requires but one branch to be so constructed); hoof-pads of rubber ([Figs. 145], [146], and [147]), straw, rope, cork, hoof cement, etc. Special forms of contraction are distinguished, and are as follows:
(a) The Contraction of Wide Hoofs.—This contraction is manifest as a concavity or groove in the wall just below the coronet, usually at the quarters, though sometimes extending entirely around the foot parallel to the coronary band ([Fig. 209]). Pain is produced in the contracted area by lightly tapping the horn, but not by moderate pressure with the hoof-testers.
Fig. 209.
Wide fore-hoof with “coronary contraction”: (a) broad shallow groove in each quarter, and disappearing toward the toe.
Green horses with wide hoofs, just from the pasture, are particularly liable to this form of contraction. As a rule, the lameness does not disappear completely until the wall has assumed its natural, straight direction by growing down properly from the coronary band.