Quarter and Toe-Cracks
Quarter-cracks are commonly found in feet of saddle horses, and are caused by contraction and pressure, and are also the result of a shoe being fitted tightly on the inner quarter, to prevent interfering, as stated in remarks on “Contraction.”
Most commonly found on the inner quarter; it commences at the coronet, extending downward, and when it extends through to the laminæ causes lameness, and is especially serious if the foot is contracted, as shown by Plate No. 16.
There are two kinds of quarter-cracks, as shown by plates Nos. 17 and 18—the lateral and the straight the latter being the most serious, if the separation commences at the coronet.
Treatment.—If the foot is inclined to contract, it should be prepared as for contraction; shorten the toe and expand the foot, under the directions already given. If lameness has resulted, a bor shoe should be fitted, so as to remove all pressure from half an inch on each side of the crack, then with a rasp cut a groove under and parallel with the coronet, extending about half an inch on each side of the crack; with a shoeing knife cut some small notches on each side of the groove, after which the edges of the crack may be cut away. (See Plates Nos. 17 and 18.) If the foot bleeds freely so much the better. After this is done a firing-iron should be applied so as to cauterize the crack. This operation having been performed, the foot should be dressed with tar every morning for about three weeks. The pressure being removed, the new growth will commence at the coronet, and extend downward, as shown in Plate No. 19, until a permanent cure is effected.
Toe-crack, more common to heavy and draught horses, is caused by want of room; the space inside the wall of the foot not being large enough to accommodate the laminæ, it causes inflammation, and breaks out at the weakest point, which is the coronet, and extends downward to the toe, causing the foot to assume the appearance of a cloven foot. (See Plate No. 20.)
Treatment.—Shorten the toe as much as possible, and then pare the sole of the foot until it will yield to the pressure of the thumb. No pressure should be allowed within half an inch on each side of the crack on the toe, for the reason that the pressure on the toe prevents the coronet from uniting. Having prepared the sole of the foot, a fine shoeing knife should be used to remove the horn that is inclined to grow inward on each side of the crack, after which a groove under the coronet, extending on each side of the crack, will be made, and the notches on each side of the groove as already directed. A firing-iron should be applied to cauterize the crack from the coronet downward. Then the crack should be cut away in the center, so as to allow the use of an “expansion plate,” as shown in Plate No. 21. This expansion plate can be made of brass or steel. It is composed of four pieces, as follows: A plate divided in the center into two equal parts, A and B (see Plate No. 21), and a thread cut in the center. Each part is made so as to fit dove-tailed into the crack, held in place with a screw C, and a burr D, underneath, to prevent the screw from pressing the laminæ of the foot. The screw, which has considerable power as a lever, forces the two plates apart, lifts up the wall of the foot which is pressing each side of the crack, and presses it outward. This being done, an open shoe should be fitted, wider than the foot, so as to expand it, which, together with the notches cut in the groove under the coronet, will cause a new and strong growth from each side of the crack, commencing at the coronet and extending downward.
The length of time required to effect a removal of the crack depends on the treatment and skill of the operator. If the foot is expanded by the plate with skill, and the nails in the shoe driven so as to prevent the wall of the foot from closing in on the crack, the plate may be removed at once; otherwise it should remain stationary, which can be done by substituting the small screw E, which will not prevent the horse from being used while under treatment. The use of the expansion plate is not necessary, unless the crack extends the whole length of the hoof. The crack extending from the coronet, partly down the front of the foot, should be treated at once, removing pressure by shortening the toe and expanding the foot, as already instructed; then, by means of the groove and notches, promote a new growth at the coronet.