All degrees of injury to the part struck by the shoe or wall of the foot may be noted. Horses that interfere lightly, wear the hair off and produce slight abrasions of the skin on the inside of the fetlock. Sometimes the skin is bruised, inflamed or scarred. Injuries to the inside of the knee and quarter are the most serious. Lameness, inflammation of the periosteum and bony enlargement may result from "speedy cutting." Deep wounds in the region of the heel or quarter may occur when a horse strikes this part with the shoe of the hindfoot in moving at a high rate of speed.
The treatment is largely preventive. No doubt many cases of interfering could be prevented by careful training and balancing of the foot when the animal is growing and developing. The feet of colts should be trimmed every three or four weeks. Interfering in the hindfeet may be stopped by noting the character of the animal's gait and the portion of the wall that strikes the part, and by practising intelligent methods of shoeing. Slight injuries should be treated by the application of antiseptic powders. The treatment for injuries to the periosteum is the same as that recommended for splints. As a last resort boots and button rings may be used for the purpose of preventing serious injury to that part which is struck by the foot.
RING-BONE.—Chronic inflammation of the articulation between the first and second bones of the digit is termed ring-bone (Fig. 35). Not all ring-bones involve the articular surfaces. The periarticular, or false ring-bone, is a chronic inflammation of the bone near the articular surface. The bony enlargement varies in size. It may form a ring encircling the part, or it may be limited to the lateral surface of the joint. The bony enlargement may be so small as to be detected only by a careful examination. Ring-bone may occur on any of the feet, but it is said to be more common in the front feet.
[Illustration: FIG. 35.—Bones of digit, showing side bones and ring-bones, and normal bones of digit.]
The predisposing cause of ring-bone is faulty conformation. Long, weak pasterns that are predisposed to strains, upright pasterns, especially if small, and exposed to concussion and jarring, and crooked feet that distribute the weight on the part irregularly are important factors in the production of ring-bones. The external causes are sprains or any injury to the region. Lameness is nearly always present. The degree of lameness varies, and does not depend altogether on the size of the bony enlargement. Large ring-bones interfere with the movement of the tendon. Lameness is most pronounced when weight is thrown on one foot, the later phase of the step being shortened and the pastern more upright. Some cases improve with rest, but the lameness returns when the animal is given hard work.
The preventive treatment consists in giving the necessary attention to the feet of young animals, by trimming the wall frequently and keeping the feet in balance and the careful selection of breeding stock. Resting the animal, keeping the foot that has the ring-bone on it in proper balance and counterirritation by means of blisters and cautery (searing) are important lines of treatment. Shortening the toe and raising the heel, if necessary, greatly relieves the lameness in some cases. Sectioning the sensory nerves that go to the part should not be practised, unless in exceptional cases.
QUESTIONS
1. Give the causes of shoulder lameness; give the treatment.
2. Describe capped elbow; give the treatment.
3. What is "broken knee"?