Fig. 25.—Uneven at ground surface.
Fig. 26.—Uneven at coronet.
Peculiarities in the formation of a limb sometimes cause an apparent error in the relative position of the foot. Thus we have horses that turn their toes in, and those that turn their toes out. The cause of this twist takes place at the upper part of the limb, and it will be found that when the toes turn out the elbow turns in and vice versâ. The farrier can do no good to this formation, and attempts to alter it or disguise it by devices in shoeing are only injurious to the foot,—little deceptions worthy of a horse-coper.
A good bearing surface is the primary object aimed at in preparing the foot for a shoe. The relative position of the limb to the foot and the proper proportions of every part of the foot are matters to be borne in mind whilst the farrier is directly forming the bearing surface for a shoe. A good bearing surface must be even, level, on sound horn, and as wide as can be obtained to give stability to the shoe. It should not be limited to the wall. If, without over-reduction, the use of the rasp leaves a firm portion of the sole as a level surface continuous with the lower edge of the wall, the best of bearing surfaces is obtained. ([Fig. 27]). The bearing surface should be level from heel to toe, and no part of it can be singled out either as unfit to bear weight or as specially capable of enduring undue pressure. No broken or diseased horn should be used as bearing surface for a shoe. The broken horn should be removed and the diseased horn must, if not entirely removed, have so much of its border cut or rasped off as will prevent contact with a shoe.