Fig. 23.—Heels low—toe long.
It is impossible to lay down any hard and fast rule to guide a farrier in maintaining the proportions of heel and toe when reducing an overgrown hoof to proper form. Feet differ much in their natural formation, some are high-heeled and some low, some are straight in front some very much sloped, some are narrow and upright, others round and spreading. In [Fig. 22] the heels are too high, and the bearing surface does not reach the transverse line at the heels. The side view shows the excessive height of heels and the slope of the wall in front too upright. Great assistance is afforded the farrier in judging whether he should remove more horn from heel or toe by the appearance of the under surface of the foot. When the heels are much above the level of the frog there is an indication for their lowering. When the wall and bars are about flush with the angle of sole between them, there is, as a rule, no more horn to spare at that part. The length of the toe may be usefully gauged by the condition of the junction between wall and sole. When the sole is sound and strong all the wall above its level—wall unsupported by sole and showing on its inner aspect marks of the horny laminæ—may be rasped down so that a firm bearing surface is obtained consisting of wall and sole.
In [Fig. 23] the bearing surface at the heels is below the line marking a proportionate foot. The toe is too long and projects beyond the transverse toe line. The side view shows the low heel and the corresponding excess in the slope of the wall in front. The lower transverse line in each figure does not represent the ground, but is added to make clear the height of heels and length of toe.
Important as it is to maintain the relative proportions between the front and back parts of the foot, it is perhaps even more important to preserve the balance between the two sides of a foot. Both sides must be left of equal height. If one side be higher than the other a disproportionate amount of weight is thrown on the lower side, and more or less strain is put upon the ligaments of the joint above. In the [Figs. 24] one limb is shown with both sides of the hoof even, and the straight line of the limb cuts squarely across the transverse line of the bearing surface of the foot. In the the other limb one side of the hoof is too high, and in the preparation for shoeing only that side will require attention.
Fig. 24.
Through constant neglect of this point some feet become more or less permanently twisted—and the twist occurs at the coronet. The ground surface of a foot or a shoe always tends to remain at right angles to the direction of the limb, and when the sides of a hoof are allowed to remain of unequal height, the higher side presses the soft tissues of the coronet upwards. As the hoof grows from the coronet the side thus increased in height is not so noticeably uneven at the lower border of the wall as at its upper, and it cannot be restored to its proper form, except by months of careful attention and slight over-lowering at each shoeing. The diagrams ([Figs. 25] and [26]) represent vertical sections through a foot from side to side. One shows the wall uneven at the base, the other shows it uneven at the coronet.