Is Conformation Relevant ?
Does a show horse win more than an ugly horse?
by James Tate BVMS MRCVS
Each sale catalogue comes illustrated with photographs of the current superstars sold at last year’s sale, but does examining a horse’s conformation really give you a better idea as to whether you are looking at next year’s superstar?
One thing is certain – a perfectly conformed horse in all areas except one bent foreleg will cost considerably less than the same horse with perfect conformation. Is it really correct to pay so much more to have little or no conformational faults, or should we be concentrating on certain faults and not others, or perhaps pedigree, size and stamp are more important? One only has to stand at the Tattersalls paddock for a minute to hear the phrase “I couldn’t buy a horse with a front leg like that”. At this point I would like to question the evidence supporting an opinion like this.
Even Secretariat Wasn't Perfect
 It is possible to name several poor horses with good conformation and several with bad conformation, but there wouldn’t be any point in doing so as you wouldn’t have heard of them. We only hear about the good horses whose conformation often becomes exaggerated by winning lots of races. There are several horses with conformation as poor as Attraction’s, but our attention is never drawn to them.
Likewise, lots of poor horses have near perfect conformation but we tend to think that the like of Secretariat (left) has better conformation because he won the American Triple Crown. This article will attempt to illustrate some aspects of conformation before examining some of the available evidence concerning its scientific relevance to performance.
A photograph of the mighty Secretariat (below) – deemed by many to have ‘perfect’ conformation. In this photograph he looks slightly ‘straight through the shoulder’ and ‘over at the knee’.
What Does Conformation Mean?
Conformation is defined as the form or outline of an animal. This may be expanded to include the relationship of form to function, in the horse’s  case, its gait. The conformation of the Thoroughbred racehorse today is a result of natural selection as well as the demands we have put on it. The assessment of a horse’s conformation is a personal process but many begin with the body, move onto the limbs and then assess the horse’s gait. The conformation of the body assesses the horse’s balance and centre of gravity but in my opinion is an underestimated area of the assessment. Conformation textbooks detail limb ‘faults’ for pages, but hardly even mention the future athlete’s body. When examining a yearling as a potential superstar surely it is vital to assess its height, length, width, girth and muscle mass, not to mention its neck, head, outlook and temperament. When examining the biomechanics of the galloping Thoroughbred, it seems obvious that its propulsion comes from its backend, hence the commonly held belief that sprinters are bigger in this area than stayers.
It also seems obvious that any horse should have a large girth allowing plenty of room for the heart and lungs, but perhaps this is even more important for the stayer than the sprinter. The result of the conformation assessment of the body is comments like short-coupled, weak behind, weak necked, narrow and tubular. I would also suggest that this is an area in which so-called amateur owners can provide valuable insight when looking at yearlings as the ‘experts’ seem to spend too much time assessing minor details and forget to look at the horse! See selecting a racehorse
 The assessment of limb conformation is quite complex but should not be debatable – a curb is a curb and back at the knee is back at the knee – conformation can change a little as the horse matures, but usually it is the onlookers assessment that varies, not the horse. The horse is assessed from a number of angles both at rest and in motion. It is important not to get too carried away with each limb section individually as the overall balance of conformation is more important. Both hindlimb and forelimb conformation is equally important but their functions should not be forgotten – the hindlimb is providing most of the athlete’s propulsion whereas the perhaps the most important function of the forelimb is simply not to break.
Inspecting Forelimbs
When considering the horse’s forelimb from side-on, the shoulder should be sloping, the knee should not deviate forward or backward and the hoof wall should slope at the same angle as the pastern.
The slope of the shoulder usually influences the slope of the pastern. The straighter the shoulder, the straighter the pastern.
Much is said about the side-on conformation of the knee in relation to the rest of the forelimb. National Hunt trainers traditionally will not buy a horse that is ‘calf-kneed’ or ‘back at the knee’ believing that it is predisposed to injuring a tendon, but on the other hand, a certain Mark Johnston goes out of his way to buy such a horse believing it to be more likely to be faster than a horse who is ‘buck-kneed’ or ‘over at the knee’. From a veterinary perspective, horses who are over at the knee have extra strain placed on their sesamoid bones and the suspensory ligament, whereas horses who are back at the knee have extra strain placed on their carpal ligaments, as well as having extra compression placed on the front aspect of their knee bones, thus knee chip fractures should theoretically be more common in such horses. However, statistical evidence for such injuries is severely lacking and as an anecdote, the over at the knee horse below had minor knee problems on its right fore before being retired as a stallion due to a suspensory branch problem in its left fore, whereas the back at the knee yearling below is just about to complete a full year’s training without taking a lame step or winning a race!
Many buyers will not buy a horse with long sloping pasterns, however is this sensible? A long sloping pastern theoretically predisposes to injury of the flexor tendons, sesamoid bones and the suspensory ligaments. However, upright pasterns, which are not considered to be anything like such a serious fault, theoretically predispose a horse to fetlock joint injuries, ringbone of the pastern joint and navicular disease.
Examples of pastern conformation:
(A) A normal angulation of hoof and pastern. (B) A long sloping pastern. (C) A short upright pastern.
When looking at a yearling’s forelimb from the front there are several terms that are widely brandished about – base-wide/base narrow, toed-out/toed-in and offset/rotated from the knee and/or fetlock not to mention whether the horse is considered to have enough forelimb strength or ‘bone’ (usually determined by the circumference of the cannon). In order to be accurate, the yearling must be standing square (with both front feet together) and in almost all circumstances the horse’s gait will mirror its forelimb conformation. None of the above conformations are considered desirable, however all are seen in the paddock for most Group/Grade One races, which is hardly surprising when it is remembered that the forelimb’s purpose is mainly not to break and thus has little relevance to the potential superstar’s future ability.
 Base-wide, toe-in conformation – the filly is also offset slightly more on her right fore than her left fore.
 Base-narrow, toe-in conformation
Below is a picture showing obvious toe-out conformation on the horse’s left forelimb. The horse’s left fore conformation can be described as carpal valgus or rotated from the knee
 
(A) Normal foot path.
(B) Foot path of a horse with toe-out conformation.
(C) Foot path of a horse with toe-in conformation.
Splints
The diagram on the left details some of the possible sites for ‘splints’ – excessive ossification of the rudimentary second and fourth metacarpal bones. Whilst splints do not bother horses for long, their presence is held against the horse as a marker of poor weight-bearing. The photograph on the right shows a splint on the outside of a left forelimb. This is less likely to have been caused by conformational faults as an inside splint which is commonly seen in horses that are offset with toe-in conformation.
The hindlimb of the racehorse is where the majority of its propulsion comes from and thus despite the fact that there is less lameness here than in the forelimb, their conformation is every bit, if not more important than that of the forelimb. Whilst some of the forelimb conformational points carry relevance to the hindlimb, for example, pastern angle and foot path, some new points are considered. When assessing the hindlimb from side-on, hindlimb/hock position is generally considered to be either ‘sickle-hocked’, ideal or ‘camped behind’/‘post-legged’. Sickle-hocked horses are predisposed to curbs (injury of the plantar ligament) and considered to have weak hind legs. However, it is also considered a ‘fault’ to have the limb too far behind the body as well as having an excessively straight hindlimb as the former condition is likely to be associated with upright pasterns and the latter condition theoretically predisposes the horse to hock arthritis and a ‘locked stifle’.
Hock Conformation
Hindlimb/hock conformations viewed side-on
‘Sickle-hocked’ ‘Ideal’ ‘Post-legged’
A diagram and a photograph of a curb on a horse with sickle-hocks. Whilst the curb will settle and is unlikely to ever cause lameness again, the fact that the horse has developed one is held against it as a marker of poor weight-bearing.
When assessing the hindlimb from behind, the onlooker is assessing pelvic and muscle symmetry, hock/hindlimb conformation and pastern/foot conformation. ‘Cow-hocked’ horses are considered to have one of the worst hindlimb conformations because there is excessive strain on the inside of the hock joint, which may cause hock arthritis. However, this comment should be taken with a large pinch of salt when assessing yearlings as to some extent this is a normal conformation in weak, growing young thoroughbreds. ‘Bow-legged’ yearlings also have a reduced value. This conformation is most commonly evident in heavily-muscled horses in which there is excessive strain on the outside aspect of the limb in the bones, ligaments and joints. When a horse has good conformation in front, and is base-narrow behind, many types of interference can occur between the fore and hind limbs.
Summing Up
So, having considered some of the conformational faults of the thoroughbred and cited some of the veterinary reasons why, it would now make sense to advise potential purchasers to avoid horses with significant conformational faults. However, surely the statistical evidence must be considered. In 2002 one of the most renowned equine orthopaedic surgeons in the world, Dr Wayne McIlwraith, presented the findings of his extensive research into thoroughbred conformation leading him to famously question the operations to correct mild deviations from the ‘normal’ limb. In fact he concluded that “a perfectly correct leg is not ideal for soundness” and some degree of carpus valgus can be a good thing. The extensive study came up with some mildly unexpected conclusions – a longer toe increases the odds of knee problems, a longer shoulder decreases the odds of a fracture and offset knees lead to fetlock problems, not knee problems. It also came up with some perhaps unsurprising conclusions – a longer pastern predisposes to forelimb fractures, thoroughbred foals achieve 95% of their full height by 18 months of age and manipulating the knee for cosmetic reasons is not helpful and can contribute to unsoundness.
McIlwriath’s study however considered just one set of results. The late Peter Calver conducted an even more extensive survey of the conformation of thoroughbred yearlings seen at the sales, which was completed by Anthony Stirk and several members of Glasgow University. The study categorised and looked for statistical differences in the performances of many different conformations, for example, back at the knee, offset, weak hocks etc. However it concluded that pedigree (sire) was more important and that it was difficult to determine if conformation actually affected performance at all, or if horses performed poorly due to other, inherited characteristics, such as heart and lung function or size.
In summary, assessing the conformation of a Thoroughbred yearling is complex, personal and of questionable relevance. The size and shape of a future athlete should be relevant, as should its limb conformation. However, neither is proven to be relevant in determining whether or not it can win a Group/Grade One race. This is the beauty of the sales – what one man loves, another hates, and no-one knows for sure who is right until at least a year or two down the line! Personally I like to follow my late grandfather’s advice: “a good big ‘un will always beat a good little ‘un!”
Thankyou to Mark Johnston racing UK for the use of this article. |
