Equine Podiatry: Evaluation and Options for Horseshoes in Today’s World.
By fourth generation farrier Dr. Katie (Cosgriff) Curry
A farrier’s toolbox needs to have a variety of tools and a depth of understanding to use each tool appropriately. The key to understanding the hoof is to have a sense of what is within the normal limits of a sound and functional hoof. The dynamic movement of the hoof and the integrity of the soft tissues that support the bone column are commonly evaluated by the human eyes and hands–the “art” of equine podiatry. Protecting the horse’s hoof started out of necessity. It then progressed into an art of blacksmithing and developed into a science with modern imaging modalities. Unfortunately, it also separated groups of people into all or none techniques and beliefs. In the best interest of the horse standing on those hooves all day, I am sharing what I have learned through the science of my education, knowledge passed down through my four generations of family farriers, the palpation of many horse legs and hooves, trimming barefoot, nailing and gluing on different shoes, observations of changes made with different approaches, and the feel of riding different horses I shoe in many different sports.
Can you name the structures inside the hoof and the function of the circled areas A and B?
Observe the X-ray and make a mental list of what you as an owner, veterinarian, or farrier would note about this image. The majority of the people asked this question will offer a variety of observations of the ABC’s: alignment, bones, cartilage, and soft tissue. The list usually includes characteristics of the sole depth, palmar angle, digital break over, relation of the P1-P2-P3 alignment/angles, bone density, cortical margins, joint space, and hoof wall angle that are combined to give an overall impression of the hoof structural soundness.
Did you comment of this area of the hoof? What are the structures in this grey area? What is their importance, what is the tissue type, and function? Does it really matter? How do the collateral cartilages, digital cushion, and frog change our hoof care management? The most overlooked aspect of the hoof care is related to the above drawing structures of A,B, and C-the functional ability of the collateral cartilages, digital cushion, and the frog to support the bone column posture from ground forces and weight of the horse. A healthy functional hoof is shown above and described with photographs and a tutorial below.
1. Palpate for a thick and fibrous digital cushion with your thumb. The digital cushion and frog are supportive tissue between the heels. They function in part to absorb impact to the navicular sesamoid bone and bursa area with proper trimming. A dysfunctional digital cushion will feel thin, soft, and fatty vs. fibrous. The digital cushion can break down or fail to develop due to lack of stimulation as a young foal from a small stable and soft ground, shoeing for a certain performance that takes away from the normal hoof function, training ground and amount of repetitive forces applied to the hoof. Also note if you can feel the joint space or condyles of the short pastern (P2) around the coronet band where the short pastern (P2) and coffin bone (P3) meet.
2. The frog is healthy and free of disease with a functional width in the back tapering to a point. The back portion of the frog is concentrated with nerves that provide important information to the horse’s brain about where the body is in relation to the surface it is on and muscles response to this information. Thrush is the most common pathology to a healthy frog second to a farrier’s knife over paring away the frog.
3. Minimal grooves on the heel of the shoe. The collateral cartilages attach to the coffin bone and are flexible. Along with the digital cushion these structures will expand in the top portion of the hoof with heel strike and reduce the excess movement of the lower heel hoof wall against the shoe that creates excess groove patterns in the shoe. Deep grooves indicate pathology of the supporting soft tissue structures.
4. The functional supporting soft tissue in the back of the hoof is also noted by the hoof trimming that has equal amounts of toe and heel hoof wall.
This type of hoof is adaptable to whatever shoe is needed to fit the owner’s use of the horse and/or financial situation and functions well barefoot.
The coffin bone provides structure and shape to the hoof while the sole callus protects the underlying vasculature that goes around the coffin bone. The lateral cartilages, coronary cushion, frog, and digital cushion allow each side of the hoof to move with independent suspension and absorb heel strike impact. The Duplo composite (made of two or more material types) horseshoe has a steel insert in the shape of the coffin bone to provide stability in the toe region and prevents the synthetic material from warping under the vascular supply. The flexible back portion of the shoe allows the natural barefoot movement of the hoof. When the lateral cartilages lose their flexibly, the digital cushion has lost or failed to develop a fibrous texture and/or appropriate thickness, the short pastern has descended into the hoof capsule from failing supportive soft tissue, and the sole depth is unable to protect the vascular supply or coffin bone I highly recommend using a composite shoe.
1. 2. 3.
1. 2 degree steel wedge applied under veterinary protocol focused on X-ray palmar angle of the coffin bone.
2. Typical heel shearing and hoof capsule forced forward by the hyper-mobile heel wall not being supported by a healthy frog and digital cushion from the bottom view.
3. Common long toe and run under heel from solid shoes with no supporting soft tissue side view.
4. 5. 6.
4.First application of the Duplo horseshoe.
5 & 6. Follow up shoeing with even toe and heel trimming.
7. Long term effect of steel shoes on an age 23 horse with a fatty digital cushion and stiff cartilages.
8. Soft tissues suspended and forced between the steel shoe bars along with loss of vertical translation create shearing forces in the heel wall material and force the capsule forward (fig. 4 and 7).
9. Soundness managed with soft wedge and Duplo for his miles left as a children’s horse.
7. 8. 9.
The soft tissue structure of both case study horse’s hooves are damaged beyond repair and can not support body weight without capsular deformation and lameness. I recommend long term application of a composite shoe that provided relief from lameness. (Noted that camera angel is different, but common observation of the hoof changes are seen.) I have also used the Duplo shoe to rehabilitate a hoof capsule and return the horse to the shoes needed for competition.
Angular limb deviation forces without independent suspension of the posterior (back of) hoof create greater forces in the joints. These horses present with “jammed” coronet bands and/or joint pain. This case study is of a mare that presents with lameness in steel shoes. Application of the composite shoe took the stress off of the limb joints by allowing the hoof capsule to move more and reduced the asymetic joint loading due to conformation.
1. Application of the Duplo horseshoe.
2. Allowing the hoof to move in vertical translation reduces the forces into the joints. The solid horseshoe does not allow vertical translation and this is commonly seen by the changes in the coronet band or displayed as joint pain by the horse.
3. Example of a horse with limb deviation, level heels barefoot, and the effect of steel shoes 8 weeks post shoeing. Duplo shoe application diminished this “jam” by allowing the hoof to move functionally.
1. 2. 3. a
The use of composite horseshoes is a valuable tool in modern farriery. It may take some expansion on your artistic side to develop a feel of healthy tissues and knowing when it may be the best alternative. I acknowledge that the trim is the most important part of the application and working with a distorted hoof capsule takes practice, time, and patient owners. The Duplo shoe is a tool to have when other measures have failed to provide the comfort, relief, or soundness required to keep the horse active. The shoes come is sizes of 4 mm increments, round or oval shape, traction/profile options, the steel piece is shape-able on the anvil or vice, and the synthetic material can be cut or shaped with a grinder to fit the hoof. Below is the Duplo on combined driving ponies.