This disease is far more frequent than is usually supposed, and many horses are ruined by it, the lameness being generally referred to the shoulder or to some other part not at all in fault.
Behind and beneath the lower pastern bone in the heel of the horse, and behind and above the heel of the coffin-bone, is a small bone called the navicular, or shuttle-bone. It is so placed as to strengthen the union between the lower pastern and coffin-bone, and to enable the flexor tendon which passes over it to be inserted into the bottom of the coffin-bone and to act with more advantage. It thus forms a kind of joint with that tendon. There is a great deal of weight thrown on this bone and from this navicular bone on the tendon, and there is considerable motion or play between them in the bending and extension of the pasterns.
It is easy to conceive that from sudden concussion or from rapid and over-strained motion, and at a time when, from rest and relaxation, the parts have not adapted themselves to the violent motion required, there may be excessive play between the bone and tendon, and the delicate membrane which covers the bone or the cartilage of the bone, may become bruised, inflamed and injured, or destroyed, and that all the painful effects of an inflamed and open joint may result, and the horse be incurably lame. Numerous dissections have shown that this joint thus formed by the tendon and bone, has been the frequent and almost invariable seat of these obscure lamenesses. The membrane covering the cartilage becomes inflamed and ulcerated; the cartilage itself is ulcerated and eaten away, the bone has become carious, and bony adhesions have taken place between the navicular and pastern and coffin-bones, and this part of the foot has become completely disorganized and useless.
Symptoms.—The degree of lameness is various; the horse may show lameness the first hundred steps, or the first mile or two, and then less or scarcely at all; he is inclined to “point” or keep the affected foot in advance of the other when standing; he may show lameness on stone or pavement and not on turf or ground; if both feet are badly affected, the horse favors his heels, has short action, and wears away the toes of his slices, leaving the heels undiminished in thickness; the hind feet may be kept well under him to diminish the pressure upon the fore-feet; in the stable, he is mostly lying down; heat of the foot and heel, especially the heel.
Treatment.—In the earlier stages when there exists only irritation and inflammation, and no changes of structure or disorganizations have yet occurred, the A.A., together with cold applications kept to the foot will be sufficient. Give a dose of fifteen drops four times per day.
In more extreme or advanced cases, the sole should be pared down and the quarters rasped, and shoe worn without nails on the inner quarter, to unbind as far as possible the imprisoned bone, and the foot kept anointed with the Veterinary Oil, and the use of B.B., the main remedy. These will be successful in the incipient or milder stages of the disease and will vastly benefit old or chronic cases.
Sand Crack, Quarter Crack
That is a separation of the fibres of the hoof from above downward—rarely crosswise. The usual treatment is to drill two holes through each side of the crack and then pass copper or iron wire through them. Both ends of the wire are then drawn and clinched down and fastened in the same way as the nails in shoeing. The crack itself is then to be filled with cobbler’s wax after having been thoroughly cleaned out. Give also, ten drops of the J.K., morning and night, to promote the growth of the hoof.
A yet better method is to properly prepare a horse shoe nail by cutting bards along in it, from head to point. Then drive the nail from one side of the crack through to and beyond the other at least half an inch from the crack. The clinching of the point of the nail will drive the bards back and firmly fasten them, and the head and point may be filed down and smoothed off. A long crack should have two nails. The shoe should be so fitted and the hoof so pared away, as to take the bearing off from the cracked portion, and as the hoof again grows down, it should be again cut away between the hoof and shoe with a saw, so as to keep the bearing of the cracked part of the hoof free. You thus rivet the broken parts together, and by taking off the strain allow the crack to grow out, and heal up. Of course a horse with a quarter crack should only be put to the most moderate work, if any, as violent exercise or hard work will be sure to aggravate and increase the difficulty, and may render a cure impossible.
Quarter crack only occurs when some brittleness or defective horny growth is present. Correct this defect by giving the J.K., fifteen drops, morning and night, and apply Humphreys’ Veterinary Oil to the crack as often.