Equine conformation: Just what are four good legs?
by Frank Gringeri
This is a very good question and rather hard to clarify. The front legs of a horse are more designed to bear weight and the hind legs are more designed for pushing off. They are not comparable to each other. They both must bear weight on the landing but the fronts receive more load as they unfold and hit the ground. Also, the front legs take on tremendous force as they land from a jump. No legs are perfectly straight and we must allow for deviation of some kind. Just how much deviation and where makes the difference between longevity and early retirement.
When evaluating legs, the three views of the horse are equally important. Frontal, side and caudal all tell a story of strength. The frontal and side views are for forelegs and the caudal and side views are for the hinds. Let’s start with the fronts, as there are many lamenesses associated with the front legs.
The two things that come to mind are straightness and amount of bone. “Bone” is the thickness of the cannon and all the soft tissue attachment we see on the side view. It’s the circumference of these two combined. It’s like the framework of a house; you can frame it with 2x4s or 2x6s – we know 2x2s won’t support the weight and strain of the house. Horses should have a proportionate amount of bone for their body weight. A big-bodied horse should have thick and coarse-looking bone together with oversized joints to take the weight and strain. I watch old Westerns from time to time and noticed the horses of 60 years ago were built for work – thick legs and joints and ample length of back to take the western saddle and the big men who rode them. With the breeding of horses for show, legs became finer and weaker with smaller feet as well. Breeding for style and aesthetics has its downfall. When an architect designs a custom home, it is an engineer, one who understands physical load, that goes over the plans and then puts their stamp on it to make sure it will stand up and be safe for years to come.
The frontal view shows the straightness of the forelegs. The forearm should be longer than the cannon. A short cannon has more strength than a long one. This also shortens all the soft tissue attachment from knee to fetlock and creates strength too. It brings the knees closer to the ground which adds strength as well. The forearm is muscular and can be developed with time and proper conditioning. The front view helps us see the bones as well as the joints. The alignment of the knee and fetlock and foot matters. This is important as the bench-kneed horse or uneven cannons can put abnormal force on the front feet. It also affects how flat the foot lands as it hits the ground. I have a three-year-old filly that hits hard on the outside on the right and is toed in and underrun on the left. Because of that, a plain shoe and level trim would not be enough to fix the problems. Sometimes to get a horse landing flat, we must trim and shim to make right what nature did not. The frontal view is also helpful when watching the horse in motion. Do they paddle or wing when they break over the ground? Or do they swing straight and land flat? The more deviated the limbs are, the more it will affect their way of going.
The side view of the front limbs tells us many things – from the ground up, the angle of the hoof and pastern. Not only the angle but the length of the pastern is very important. Both pasterns should be of equal length and of the same angle. With cattle, they evaluate feet and pasterns together, noted as F+P. With horses, the pastern is equal to one half of the foot as it will influence the force placed upon it. Too long a pastern and uneven pasterns will put abnormal force on the hoof which makes it more difficult to maintain proper hoof axis. Hoof axis is very important to stave off caudal heel lameness and navicular syndrome.
The knee set is also viewed from the side. “Over at the knee” or “back at the knee” describe the straightness from forearm to knee to fetlock. Slightly over is more desirable as the back at the knee structure hyperextends the joint when set in motion and creates abnormal load. The knees of a horse are one area where there is much lameness, especially when pressed to the limit like in racing and high speed turning. If the joints are sufficient in size and shape, there will be a better chance for longevity and soundness.
The caudal view (looking directly from behind the horse) tells us straightness of the hinds but also base wide or base narrow. Just how level the hips are can also be viewed. If one is dropped, slightly lower than the other, it will create an unevenness in motion. The length of cannons and pasterns cannot be overlooked. It’s easy to pick up on pasterns of different length but more difficult to see cannons that are mismatched. The angle of the hind pastern should be somewhat upright and also a matched pair.
The side view of the hind limbs is important. Starting at the top, there should be a noticeable angle from stifle to hock. A “posty-legged” horse will be straight up and down and this will put more force on the fetlock causing it to run down. The gaskin should be wide and flat and the hock should be as wide and large to match. All the muscular strength of the haunches is not worth anything if the gaskin and hock are not of size to transmit the force and power from above. Oftentimes I’ve seen big, oversized haunches with small hocks on the bottom, followed by fine cannons and small fetlocks. The muscular strength never got to the ground and these horses got uncomfortable at an early age.
We touched upon two elements, straightness and bone. The size of the horse does have a bearing on how long its legs will hold out, depending on use. Horses over 16.2 will have to be managed with extra care. It’s not just the weight factor; the center of gravity on taller horses places more strain on the legs, especially when turning and when working on a circle. The lateral force increases with height and size and this puts a lot of strain on soft tissue, namely tendons and ligaments. Careful conditioning and timely workouts will keep them sound.
It takes a trained eye to evaluate the structure of the horse. The layman just won’t have the time or background to make a good choice when selecting a horse for a certain discipline. Even with all we know and understand about conformation, it is no guarantee that the horse will withstand the rigors of training. Some horses outperform deviated limbs because they are so strongly built on the top. To be honest, I’d much rather start out with strength than something more poorly built that is weak to begin with. It takes years to train a horse to do what we want it to do so I put longevity at the top of the list. That means starting with a good strong structure.
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