By equine lameness and performance specialist Dr Sue Dyson
Gillian asked me to write an article ahead of the ‘Prevention is Better than Cure’ webinar series we are doing in October. It strikes me that people in general do not look critically at horses’ feet and think about what they are seeing.
There is an old saying, ‘no foot no horse’ and it is true to say that foot-related pain is the most frequent cause of forelimb lameness in horses of all types and work disciplines. It is therefore critical to assess hoof capsule shape and size. Although there are many potential anatomical structures that may be injured and result in foot-related pain, and for each injury type the causes are often multifactorial, there is no doubt that foot conformation may be influential.
Sue Dyson, copyright 2024
So, when assessing a horse for purchase, it is vitally important to look objectively at the front feet. I have a check list of questions:
Are the feet a pair or is one narrower than the other, or does one have a steeper hoof wall – so is more upright? – asymmetrical or uneven front feet.
2. Do the feet face forwards when viewed from the front or is the horse toe-in (pigeon toed) or toe out?
3. If I view each forelimb from the front, is the hoof capsule reasonably symmetrical or is it ‘flared’ to the inside or outside?
4. If I view each forelimb from the front is the foot bisected by a vertical line that bisects the forearm and cannon region, or does this line result in there being more of the hoof capsule on one side of the line than the other?
5. If I view the feet from the front is the coronary band horizontal or does it slope from one side to the other. (Has one heel been ’shunted’ upwards?)
6. If I view each foot from the side is the coronary band straight or curved?
7. If I view each foot from the side is the dorsal (front) aspect of the hoof capsule parallel to the heel or is the heel at a much smaller angle to the ground?
8. If I view each foot from the side are the horn tubules parallel or are they at more of an acute angle (smaller angle) towards the heel.
9. If I view each foot from the side are the hoof wall rings parallel or do they diverge towards the heel?
10. If I view each foot from the side is the dorsal (front) aspect of the hoof capsule straight?
11. If I view each foot from behind are the heel bulbs or similar height or is one higher than the other?
12. Are the toes of each hoof capsule excessively long?
13. If I pick up the foot and look at the underneath of the hoof capsule are the heels rolled inwards and forwards?
14. If I pick up the foot and look at the underneath of the hoof capsule is the height of each heel bulb similar?
15. Does the horse have a narrow tall foot with a deep frog cleft and sulci? Are the the cleft and sulci clean and firm or soft, squishy ± smelly
16. Is the sole of the foot concave or flat? Is the sole abnormally soft and compressible with your rhumbs?
17. Does the hoof capsule have any longitudinal cracks or any defects close to the solear surface suggestive of poor horn quality? Or have the feet been painted with hoof oil or hoof paint thus concealing the appearance of the horn?
18.If the horse is shod, do the shoes fit the foot and is each shoe worn evenly?
19. If the hoof capsules are excessively long, how will they look when appropriately trimmed? Can I tell whether or not the well-trimmed hoof capsules will be symmetrical or not?
20. Does the horse have special shoes and / or pads and if so why? Does this reflect a previous problem?
So there is a lot to look at - and this is before we have seen the horse move! Bear in mind that a horse may stand toe-in or toe-out but have a straight limb flight and land reasonably symmetrically when moving at walk, trot and canter. However, a horse may look as though it has good foot conformation, but may not have a straight limb flight and may land repeatedly towards the outside of the hoof when moving.
Also bear in mind that the feet cannot be properly assessed when standing on bedding in a stable or on grass. The feet need to be examined with the horse standing on a firm surface in good light in a situation where you can look at both front feet from all angles, without the horn being concealed by oil, grease or paint.
Unlike many aspects of equine conformation, there is a lot of evidence-based information about hoof capsule conformation and the effect that it can have on movement patterns, loading, injury risk and longevity of sports horses in competition.
It cannot be said that a horse with good hoof capsule conformation will necessarily stay sound, but there is no doubt that certain variants of hoof capsule morphology may predispose to foot-related problems and therefore merit attention when you go to look at a horse with a view to purchase. No situation is ever black and white; there are always exceptions to the rules and longevity as a riding horse depends on many things, especially the skill of your farrier, regular trimming approximately every five weeks and the conditions in which a horse is kept and how it is worked.
Let’s consider in more detail a few of the problems that I have already highlighted.
Asymmetrical front feet
A horse may have asymmetrical or uneven front feet because of the way it has preferentially grazed, for example placing the right forelimb in front of the left most of the time. Alternatively it may be an inherent, genetically influenced asymmetry, which was not addressed adequately since early trimming as a foal. It may reflect the development of a flexural deformity of the distal interphalangeal (coffin) joint as a foal. Or it could reflect sub-clinical or previous lameness. Whatever the cause, it has been shown that horses with asymmetrical front feet leave the sports horse population earlier than horses with symmetrical hoof capsules. Moreover, there are differences in vertical forces, and horizontal braking forces, and fetlock sinking between two asymmetrical front feet within a horse, which may predispose to the development of injury.
Pigeon toed and medial flare or toe out and lateral flare and inwards collapse of the medial aspect of the wall
When assessing toe in or toe out conformation we need to determine whether this involves only the hoof capsule or the entire pastern. The latter will result in a greater biomechanical impact on loading of the proximal interphalangeal (pastern) and distal interphalangeal joints. There will be a natural tendency for the hoof wall to grow more towards the side that the foot turns and this will in turn alter force distribution and influence breakover. So, the farrier needs to pay particular attention to this at each trimming.
Alignment of the hoof capsule with the upper parts of the limb
If the hoof capsule and upper parts of the limb are not in vertical alignment when viewed from the front and the shape of the hoof capsule is markedly asymmetrical this will be mirrored by the shape of the distal phalanx (coffin bone) within the hoof capsule. This will result in abnormal loading of the distal interphalangeal joint. Usually there is more foot and pastern lateral (to the outside) of a line that perpendicularly bisects the upper part of the limb, resulting in overload of the medial part of the joint, predisposing to osteoarthritis or traumatic bone injury. This conformation cannot be altered and should therefore be avoided.
Heel height and heel shape and orientation of the horn tubules
A low heel conformation is mirrored by the orientation of the distal phalanx, the navicular bone and the deep digital flexor tendon. This potentially places more strain on the suspensory apparatus of the distal phalanx (the laminae) and increases strain in the deep digital flexor tendon and force applied by the deep digital flexor tendon to the navicular bone. If the horn tubules are compressed, so that they are at a more acute angle to the ground at the heel compared with the front of the foot, because the heel bulbs collapse and roll inwards the entire biomechanical function of the digital cushion, the blood vessels and ungular cartilages may be compromised, negatively influencing shock absorption. Low collapsed heel conformation is bad.
Shape of the coronary band
In a normal horse the coronary band should be straight when viewed from the side and from the front. If the coronary band is of curved or of uneven height medially compared with laterally this may reflect previous lameness or impending foot related lameness.
Spacing and alignment of the hoof wall rings
In a normal horse the hoof wall rings are parallel with each other and the ground surface. They may vary in their separation reflecting in part hoof wall growth and nutrition. If the hoof wall rings diverge towards the heel, then this can reflect previous laminitis that may have been subclinical. Don’t miss this especially in a horse with an excessive body condition score which may have insulin dysregulation and at risk of future episodes of ‘footiness’ or overt lameness because of laminitis.
So, remember, ‘no foot no horse’. ‘Buyer beware’. Look carefully, observe and think about what you see and seek advice from your veterinarian and your farrier. Be aware that an insurance company may exclude cover for the front feet if abnormalities are described on a pre-purchase examination certificate.
If you enjoyed this article join Sue on her series of webinars Prevention is Better than Cure In this series of three webinars, independent consultant and lameness specialist, Dr. Sue Dyson hosted by Gillian Higgins will explore what makes a 'good’ horse. Packed with scientific, evidence based facts, these talks will prove to be interesting, informative and invaluable.
Assessing ConformationWhat Does Good Look Like? with Dr Sue Dyson
6.30pm (BST) Wednesday 9th October 2024
In this webinar, Sue will consider what makes a good horse in terms of temperament, conformation, suitability and sustainability. It is of interest to all riders who would like to understand more about their horse as well as those wishing for some pointers to consider when looking to purchase the horse of their dreams. Because no horse is perfect, Sue will examine which issues are manageable for purpose and which are best avoided.
Promoting Longevity Maintaining Soundness and Optimising Performance with Dr Sue Dyson
6.30pm (BST) Wednesday 16th October 2024
This webinar will examine how to keep your horse in the best possible condition appropriate to his role in life. Sue will explore how, through careful management, astute observation, prompt intervention and a good understanding of anatomy and biomechanics, we can reduce the risk of injury whilst maintaining soundness, good posture and optimal performance.
Not Quite Right?? Improving Poor Performance with Dr Sue Dyson
6.30pm (BST) Wednesday 9th October 2024
This evening will consider how to recognise, and what to do, if we feel our horse is, ´not quite right!´ How do we decide if a problem is caused by pain, weakness, behaviour or habit? What actions do we need to take? When do we need to bring in outside help or expert assistance? How do we find the best person to consult? What can be done to manage the situation? Sue will look at a selection of scenarios and discuss how to decide on and how to manage a variety of problems.
Great informative article.