Evaluating Horse Conformation Pt 6

Problems associated with horses that are either cow hocked or base narrow include additional stress placed on the leg and joints (bog and bone spavins can be associated with cow hocks), as well as potential interference when the horse moves due to part of the legs being closer together than normal. Horses that are bow legged have the opposite condition of cow-hocked horses. Bow legged and base wide horses often have trouble being able to properly use and push off of their hind legs and therefore can lack the athletic ability of a horse with proper conformation. When examining a horse's hind legs from a side view with the horse standing squarely, you should be able to draw a line perpendicular to the ground that touches the point of the horse's rump cheek, the back of the hock and the back of the fetlock (Figure 15). This conformation of the hind leg allows the horse to carry weight well over its hindquarters and reach under itself as it moves to allow for maximum power. A horse that is sickle hocked has too much angle, or "set," to its hocks. A horse with sickle hocks will look like it has too much bend at the hock when standing squarely. When the hock angle looks normal on a sickle-hocked horse, the hind legs will often be farther behind the horse than they should be (camped out). This puts extreme stress on the hock joint and surrounding tendons and ligaments and can lead to conditions such as curbed hocks, bog spavin and bone spavin. Horses that have the opposite conformation of a sickle-hocked horse are said to be post legged. These horses have extremely straight angles to their hocks. This puts extreme strain on the hock and can also cause bog spavins and bone spavins. Lower leg conformation A final important consideration when examining the horse's legs, both front and hind, is the angle and length of the pastern. The pastern acts as a shock absorber for impact from the hoof landing on the ground and affects the soundness of the entire leg. The pastern angle typically matches the shoulder angle and should be approximately 45 degrees when measured from the horizontal line of the ground (Figure 16-A). The pasterns should be long enough and sloped enough to absorb impact. Too straight of a pastern angle (often resulting from pasterns being too short) causes increased jarring of the leg and joints when the horse moves and can lead to windpuffs, enlargement of the sesamoid and joint pain (Figure 16-C). Pasterns that are too straight may also affect the navicular bone, causing it to come in contact with the short pastern bone and leading to erosion of the bone or the formation of bony spurs. In spite of the problems associated with pasterns that are too short and straight, it is also possible for the pastern to be too long or too sloped (Figure 16-B). Horses with this problem have an increased in flexion of the fetlock joint, potentially allowing for hyperflexion and damage to the joint and surrounding structures. Another important consideration when examining the pastern angle is to check that the pastern angle and the hoof angle are approximately the same. A horse with a very steep hoof angle when compared to its pastern angle is said to be club-footed (Figure 17). This is undesirable because the steep angle of the horse's hoof will not only change the way it moves but also makes the horse prone to foot and leg lameness. Additionally, it is not desirable for the horse to have a hoof that is much more angled in comparison to the angle of the pastern. How Structural Correctness Influences Way of Going Leg conformation significantly impacts the way the horse moves. A horse with straight, correct legs has maximum range of motion and moves cleanly and correctly without any interference (hitting one leg against another). Horses with structural deviations in their legs do not generally move their legs straight forward when traveling. Horses with pigeon toes typically "wing out" when they move.