Equine Conformation: Built to Last
Making demands of the wrong horse can hasten lameness.
Lameness is an alteration in the way a horse moves a limb or multiple limbs. 1 It generally causes pain and suffering for the horse and is responsible for the greatest loss of use among horses and the greatest economic impact on the industry.
A horse can become lame from a variety of causes (conditions or ailments), involving almost any anatomic region within a limb. 2 Poor conformation may result in a greater risk of injury, difficulty in training, and greater lameness issues. 3
Conformation refers to the shape or structure of a horse, and it can impact a horse’s athletic ability. 4 Generally, a horse’s neck should be one and a half times the length of the head. The neck should tie into the horse’s body fairly high to provide good chest space. The shoulder and pastern angles should be between 40 and 55 degrees. A horse can move best with a short back and long neck. Correct leg structure can improve performance and reduce lameness.
Proper conformation is important to allow the horse to be balanced, powerful, and maneuverable as well as to maintain soundness over its lifespan. 5
It can also be extremely important in preventing or delaying – or hastening – lameness, said Doug Thal, DVM, Dipl. ABVP, owner of Thal Equine, Santa Fe, New Mexico, and creator of Horse Side Vet Guide®. For example, horses with pigeon toe (inward angulation from the fetlock to the ground) put uneven compression on the lower limb joint surfaces and torque on the joint capsules and supporting ligaments. This predisposes to arthritis of these joints of acute injuries, such as sprains. Another example is a horse with long-backed conformation, which may lead to difficulty doing work that requires lots of engagement (dressage) or hard stops and turns (western performance).
Conformation can be evaluated through a general knowledge of conformation as well as the potential owner’s goals regarding the activity in which the horse will be engaged, said Dr. Thal. “Ideally, you don’t purchase a horse that has significant conformation problems, or you purchase a horse with conformation that is at least compatible with what you will be asking of the horse.
“Think of it this way,” he said. “If you want to be an NFL offensive lineman, you will benefit by being of a certain conformation – say, 6 feet 5 inches, tall and heavy set. On the other hand, if you just want to be able to take a walk in the park, you may not need any specific conformation, but you still benefit from having healthy, anatomically correct joints. Sure, you can still get around the park if you have a very crooked leg, but it hampers you.
“There is a wide range of what constitutes pleasure use,” he continued. “You may get away with a lot more conformational deficit in horses that you ask very little of.” People can have a great time riding a horse without even realizing it is lame. So, in this case, ignorance is bliss, except for the horse.
Conformation is unalterable, at least for the adult horse, said Dr. Thal. “The word ‘conformation’ implies the basic bone structure of the horse, which is genetic and developmental. In the adult horse, once the bones have stopped growing, you cannot alter the bone structure significantly, though you can modify the musculature and to some extent the position of certain joints through different types of exercise, training, and riding programs. That might significantly change the horse’s appearance and improve function.”
Veterinarians have some latitude with the young horse, he said. Long bones lengthen at a region of the bone called a growth plate. As the young horse matures, these fuse at variable times. The shorter of these bones tend to have growth plates that fuse when the animal is very young. Prior to fusion, the veterinarian can change the way the growth plate grows through hoof trimming/shoeing and surgical procedures, such as transphyseal bridging or periosteal stripping. (Lower cannon bone growth plates functionally typically fuse at 8-12 weeks of age, whereas the radius – the upper arm bone – fuses at 2+ years.)
Conformation is one of the most reliable predictors of both athletic ability and soundness in most horses. 5 Of course, there are exceptions. Take Seabiscuit, the legendary champion Thoroughbred racehorse of the 1930s.
Seabiscuit was the opposite of what a buyer looks for when purchasing a racing prospect. 6 In normal horses, the front legs are straight when viewed from the side. Seabiscuit was over in his knees, a condition that typically causes horses to stumble. He also had long cannon bones on his rear legs, resulting in his hocks being higher than his knees. Most equestrians agree that a short cannon bone is preferable to a long cannon bone for almost all horses.
Notwithstanding Seabiscuit’s story, evaluating conformation involves analyzing a particular breed and type of horse for balance, structural correctness, way of going, muscling, and perhaps breed and sex character. 7 (Breed character refers to how well a horse represents the ideal standard for its breed and should not take precedence overbalance, structural correctness or way of going.)
Balance is arguably the most critical aspect to evaluate. It is essential for both quality of movement and performance in any event and is determined by the horse’s bone structure. Balance refers to equal distribution of muscling and weight from the front of the horse to the back, from its top to its bottom, and from side to side. However, balance is not determined by the horse’s weight but instead by proper angles and proportions of different parts of the body (e.g., the shape of the shoulder, ratio of the topline to the underline, and hip and wither height). In other words, a horse can be light-bodied or heavy-bodied and still be balanced if its bone structure allows for equal distribution of that weight.
Structural correctness is critical for soundness as well as correct and clean movement. It is determined by proper structure and alignment of bone, particularly pertaining to the legs. Conformational defects cause deviations in the way the horse moves and places its hooves on the ground, and therefore affects the way impact travels up the leg. Such defects can affect the horse’s way of moving and can also lead to future lameness due to excessive stress placed on certain areas of the body. (A horse carries approximately 65% of its weight on its front legs, thereby making the front legs the most likely area for injuries resulting from trauma or concussion.) The more structurally correct the horse’s legs are, the more evenly distributed the impact will be and the less likely the horse will be to have chronic or acute injuries.
Way of going, or tracking, refers to the way the horse moves and is significantly affected by leg conformation. A horse with straight, correct legs has a maximum range of motion and moves cleanly and correctly without any interference (i.e., hitting one leg against another).
Muscling is also a consideration when evaluating the horse, though not nearly as important as balance and structural correctness. The quantity, quality, and distribution of muscle are evaluated when looking at the horse from its sides, front, and back.
The ‘ideal’ conformation?
Horsemen and women may be on a search to find prospects with “perfect” conformation, but their search will be a long one. Conformation is a subjective assessment and is rarely found. 8
Riding discipline can influence a conformation fault’s degree of impact. A horse that is back at the knees, for instance, might not be a suitable racehorse or showjumper, but he could make a great hunter pleasure mount. Likewise, a horse with straight, posty hind-limb conformation might be prone to stifle issues and unable to perform well in events that require hard stops and turns.
Horses with mild conformational faults may experience added stress or wear-and-tear on their bones, joints, and supporting soft tissues. Owners need to be willing to address these issues and take preventive measures such as icing, wrapping, diligent shoeing, and using joint supplements, among others.
“If you have a horse with a conformation limitation or problem, consider their use,” said Dr. Thal. “Can they continue to perform at their intended use, or do you need to change your expectations? If they continue to be ridden, then all you can do is control that you can provide excellent routine hoof care, good fitness and conditioning (more intense exercise than the horse will actually experience), and good general care/nutrition.
“Consult with your equine veterinarian when you have a question or notice anything that might be a problem. Catch problems early. Diagnose them and treat them properly.
“Consider high-quality joint supplements but recognize that … most of their claims are unproven. That said, some oral supplements and injectable medications have their place in prevention/management. Let your equine vet help guide your choice of supplements and medications.”
It is the veterinarian’s responsibility to educate owners about conformation and its potential impact on the horse, said Dr. Thal. Ideally, for everyone, that is done at a purchase exam. Not only does the veterinarian identify the issue, but he or she takes the time to teach the owner what they can learn from a purchase exam, so they can make a better choice next time.
“Some vets want to avoid that conversation. I don’t think it should be a difficult conversation though. Obviously, it depends on the health of the vet-client relationship. But if our job is to look out for the well-being of the horse, and we are equipped with the knowledge to do that, then it should be our role. We should be guided by what is best
1 Horse Side Vet Guide®, horsesidevetguide.com
2 Understanding Lameness, American Association of Equine Practitioners, aaep.org/horsehealth/understanding-lameness
3 Conformation: form to function, Omega Fields®, omegafields.com/blog/conformation-form-to-function/
4 Conformation of the horse, University of Minnesota Extension, extension.umn.edu/horse-care-and-management/conformation-horse
5 Evaluating Horse Conformation, University of Georgia Extension, https://extension.uga.edu/publications/detail.html?number=B1400&title=Evaluating%20Horse%20Conformation
6 Seabiscuit: 10 Facts about the Horse That Captured Our Hearts, Horse Racing Sense, horseracingsense.com/10-seabiscuit-facts-race-horse/
7 Evaluating Horse Conformation, University of Georgia Extension, extension.uga.edu/publications/detail.html?number=B1400&title=Evaluating%20Horse%20Conformation
8 Horse Conformation Flaws: Piecing Together What We Know, The Horse, thehorse.com/17465/7-conformation-flaws-piecing-together-what-we-know
Photo 1 credit: istockphoto.com/CasarsaGuru
Photo 2 credit: istockphoto.com/imantsu