2017 SPONSORED BY International HOOF CARE Hoof-Care Summit Coverage Sarah Evers Conrad

undreds of farriers and equine veterinarians from around the world gathered in Cincinnati, Ohio, Jan. 24-27 to talk hoof-care practices and innovations. The was on the scene to cover some of the most practical of the more than 100 sessions, roundtables, and how- Htos. Read on to find out what’s cutting-edge in the world of equine hoof care.

10 take-homes from the 14th annual edition of this equine foot-focused event I S T O CK.C M

Trimming and Shoeing Techniques Can A horse’s stride has two phases: Affect How Move 1. The nonweight-bearing swing phase; and Farriers must understand biomechanics and 2. The stance phase, when the hoof is in con- the forces at work in a horse’s hooves to make tact with the ground. appropriate trimming and shoeing decisions. Stance is further divided into three phases: Jenny Hagen, PhD, professor and researcher 1. Landing, which starts with the initial ground at Leipzig University’s Institute of Veterinary contact; Anatomy, in Germany, explained how farriers 2. Midstance, when the horse’s body is directly can help horses move better using trimming over the supporting limb and experiences and shoeing techniques. the greatest ground reaction force (GRF,

TheHorse.com The Horse 1 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE

which is exerted by the ground on the video revealed pressure distribution and ■ Breakover This varied horse to horse, horse); and hoof-ground contact in the stance phase, but more cases showed pressure on 3. Breakover, which is the process of the which could allow veterinarians and far- the lateral aspect of the toe than other heels lifting off the ground, rolling over riers to identify where hoof problems are parts of the hoof. the toe, and the toe leaving the ground. located. Effects of Trimming and Shoeing While Hagen has been studying the horse’s Hagen and her team discovered the trimming, a farrier tries to optimize the stance phase because trimming and shoe- following: initial contact and hoof load during mid- ing can affect the forces on the hoof and ■ Initial contact How the hoof first im- stance and facilitate breakover, although limb during this phase, and she wants to pacted the ground varied greatly. The it’s often difficult to improve all these know exactly how. most common landing patterns were aspects, said Hagen. Farriers can only impact the swing plane landing (all parts of the hoof “If you would like to change the initial phase indirectly, she said. contacting the ground simultaneously, contact, gait pattern, or the stance phase “All biomechanics and all strains af- which occurred in 35-42% of cases) and of the horse, you need to aim specifically fecting tendons, ligaments, and joints lateral landing (when the outer side of for it,” said Hagen. “You can’t just trim have differences depending on the stage the hoof landed first, which happened statically or geometrically (to the shape of of the stance phase,” said Hagen, adding in 35-40% of cases). Toe-first landings the horse’s foot). You really have to check that the center of force (also referred to made up 15% of the cases. Medial (the with the functional things like the walk as center of pressure, where all forces inner side of the hoof landed first) and and how the horse is moving.” become equal) also changes based on the heel landings were 2% and 2-3% of the Changing how a hoof initially contacts phase. cases, respectively. She noted a weak the ground also often influences load In their recent study Hagen and col- correlation between initial contact distribution during the midstance phase, leagues collected data from 75 sound and mediolateral (side-to-side) load Hagen said. For each individual case, Warmbloods using an inexpensive mobile distribution. farriers must judge whether correcting sensor system called Tekscan, which mea- ■ Midstance The lateral hoof side was the hoof’s initial contact toward a plane sures pressure across the various parts most affected by force during this landing outweighs the disadvantage of of the hoof. The resulting images and phase. an unequal loading during the midstance

How Form Affects Function

Cause Lack of regular scheduled trimming and misconception of what the bars do. Effect Without properly placed bars, the back half of the foot is not supported resulting in corns, abscess and pinched heels. Solution Trim the bars to their point of origin. Result A healthier foot that functions normally.

Vettec • Orange, California • 1.800.483.8832 • www.vettec.com

EU Customer Care • +420 800 260 001 • www.vettec.net VA.0816.THORBARS

TheHorse.com The Horse 2 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE phase, when the strongest forces affect the limb, she added. While farriers can trim to change the center of force more easily in the dorso- palmar (toward the heel) then mediolater- al (middle) position, it’s difficult for them to change the location of the individual breakover in this manner. Shoes’ Impact on Stride Farriers can also impact the horse’s stride by changing shoe weight, height, and surface. Each horse’s hoof-ground contact is different, and the effect of trimming and shoeing depends on posture and limb conforma- tion, , the stage of the stance phase, and manufacturing of the Cour t es y D r. Br i an Ha mp son shoes. Dr. Brian Hampson documented hoof morphology changes, including heel bulb length, toe length, “With the application of modified sole depth, and more, resulting from various trim methods. , such as bar shoes, open toe shoes, or other surface modifica- models on hoof morphology (form and horses with healthy, disease-free hooves tions, specific regions of the hoof can be structure). they thought they could change. Each far- directly relieved to support the recovery Study Overview Hampson evaluated rier started with hooves that had not been of diseased parts of the hoof,” said Hagen. 22 horses from the United States and trimmed in the previous six weeks. While farriers can apply modified Germany on which one of four trim types The Trimming Methods Hampson horseshoes to adjust initial contact and was performed over a 12-month period. described the four schools’ trimming facilitate breakover, they shouldn’t use His goal was to document morphologic methods to the audience: them if the result is instability when changes associated with various barefoot ■ “Barefoot Hoof Orthopaedics (BHO)” the horse is in motion, especially with hoof care models and to determine if from Dr. Konstanze Rasch of Germany: wedges, studs, or rocker shoes, Hagen hoof capsule changes occurred in relation This technique doesn’t allow significant said. She added that wedges put pressure to them. He also aimed to find out if the adjustments to the hoof wall from trim- on the heels, which can have negative palmar soft-tissue volume within the foot ming underneath, because the belief long-term effects on hoof growth and changed over 12 months. He didn’t seek is they stress the joints above, he said. shape, especially if a horse tends to have to determine if one trim method was bet- Instead, the farrier thins the wall from underrun heels. If a farrier needs to use ter than another. the outside and lets the natural move- wedges, Hagen recommended using long ment of the horse trim the hoof down. wedges made of soft material. ■ “Natural Hoof Care” from Dr. Tina Hagen stressed that farriers shouldn’t (Trimming) should be Gottwald of Germany: He said this rely on orthopedic shoes long-term. Just method involves using a trim similar to as people take antibiotics for a specified based on a combination those used for wild horses (the “mus- amount of time to treat a specific illness, of measurement ‘guides’ tang roll”) by rolling the hoof wall’s a farrier only needs to use an orthopedic ground surface all the way around and shoe temporarily to correct a specific and a good knowledge taking it back to the white material/ problem. These shoes can affect pressure of the biological and wet line. distribution on the hoof capsule, leading ■ “Pacific Hoof Care Practitioners to shoeing intolerance or other problems, biomechanical conse- (PHCP)” from Sossity Gargiulo of the she cautioned. quences of hoof length United States: This method involves keeping the outer hoof wall tubules Trimming’s Effects on and angle changes.” from interacting with the ground by Morphology dr. brian hampson using a trim similar to trims Farriers use a wide range of trimming by rolling the hoof wall almost all the techniques to improve the health and Hampson’s research team analyzed way back to the heel, he said. structure of each equine foot and hoof data provided by four trimming schools ■ “HoofPrint Method” from Cheryl capsule on which they work. that agreed to have farrier students trim Henderson of the United States: This Brian Hampson, PhD, co-founder of horses every four to six weeks according trim creates a rocker toe and a thinner the Australian Research Unit at to their taught trim method and share hoof wall. the University of Queensland, in Australia, their results. Photos and radiographs Key Study Findings The study results presented the results of a study in which were taken before and after each trim. confirmed that trimming can change he looked at the effects of four trimming The farriers/trimmers selected study hoof capsule morphology. Some changes

TheHorse.com The Horse 3 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE were positive, such as increased palmar meat to absorb that shock.” ­symmetrical feet, and hoof morphology ground support length and reduced toe Hampson said he’s not a fan of the ex- varied between horses; length. Hampson’s team viewed result- cessive mustang roll, which involves trim- ■ No change occurred in distal phalanx ing reduced sole depth and excessive ming the hoof wall into a rolled look all (coffin bone) length, lamellar zone shortening of the toe as negative effects of the way around the hoof so that the horse thickness (the distance between the trimming. bears more weight on the inner hoof laminae and the outer hoof wall), or Hampson and colleagues found that wall and the sole. He said it’s not natural sinker distance (the depth the coffin hoof capsule changes might not align like many mustang roll fans promote. In bone had sunk over time into the outer with each trimming school’s philosophy his work with wild horses, he said he’s hoof). There was no change overall or be as significant as each trim’s advo- never seen a wild horse’s foot look like in heel bulb length, palmar angle (the cate proposed. Finally, they found that the mustang roll unless the horse was angle the wings of the coffin bone make palmar soft-tissue volume did not change on the verge of death, traveling excessive with the ground), dorsal hoof wall relative to hoof capsule changes over the mileage to survive drought conditions, or angle (the angle the outside of the hoof year-long study. climbing rocky mountainous country to wall makes with the ground at the toe), In his summary, Hampson described access feed. and frog width in any group; the importance of the hoof wall, espe- “I don’t see the point in cutting (the ■ All the groups except BHO reduced cially at the toe and in the buttresses (in hoof wall) off, and I really haven’t had the distance from the tip of the distal the back near the heels). “It’s thick here anyone give me a good explanation for phalanx to the lamellar zone; (in the back) because the heels slam on why that’s done,” he said. “I’m not con- ■ The horses had an average 20% reduc- the ground in the heel-strike in weight- vinced that’s a natural horse’s foot.” tion in sole depth (2.9 millimeters) bearing,” he said. “In toe-off, there are Additional Observations He and the with no difference between the four large movement forces in the dorsal foot other researchers also found that: methods; (the front hoof wall), so you need a lot of ■ None of the horses had perfectly ■ All but the BHO horses had an average

cause painful, bleeding conditions Solution Trim heels back to provide proper weight bearing surface and balance the remainder of the foot. Apply a pour-in pad to provide necessary frog and sole support. Address stress to the coronary band above the crack. Debride the crack, removing bacteria and relieving pressure. Stabilize the crack with a repair.

Result Heels are where they should be, foot is balanced, and coronary band is level. The crack is stabilized allowing hoof wall to grow out. Have a hoof problem? Contact us to talk it over. 1.800.483.8832 [email protected] Vettec • Oxnard, California • 1.800.483.8832 • www.vettec.com Utrecht, The Netherlands • +(31) 30 241 1823 • www.vettec.net VA.0116.THORQRTR

TheHorse.com The Horse 4 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE

26% reduction in toe length (range and a good knowledge of the biological ■ Balance issues; of 8% from one group to 40% from and biomechanical consequences of hoof ■ Shoeing; another); length and angle changes,” he said. “This ■ Stress from certain types of work, such ■ Hoof length didn’t change signficantly, is where art and science combine to pro- as repetitive speed training; and but PHCP achieved a 10-millimeter duce the best results for the horse. Hoof ■ Diseases, such as , white line reduction while BHO achieved a care recipes work sometimes for some disease, or canker. 7-millimeter­ increase; horses but will be detrimental for others.” Early Hoof Morphology Managing ■ The horses’ dorsal foot length de- The study results give veterinarians, hooves to prevent distortions starts at creased by 25% on average, while the farriers, and horse owners more informa- foaling. When horses are born, their BHO group experienced no reduction; tion with which to make educated deci- hooves are almost perfectly symmetrical ■ Mean palmar foot length increased by sions about hoof care, he said. and covered with a soft deciduous (mean- 8% (7 millimeters, with a range of 3-10 ing it will eventually shed) material and millimeters); Dealing With Hoof Capsule have soft soles to protect the mare’s birth- ■ Heel angle (the one between the heel Distortion and Dysfunction ing canal. Hooves harden after birth. wall and the ground) increased by 2% What do a dish, a crack, a flare, and a The typical newborn foal hoof is very on average (range of 5.8-degree reduc- sheared heel have in common? All these contracted with underrun heels, which tion to 6.2-degree increase, with the problems are forms of hoof distortion. quickly shift back into the proper posi- increase not being significant); tion, said Morrison. He also said it’s nor- ■ Heel width was reduced by 6.3 mil- mal for foals to rock back on their heels, limeters on average (ranging from You have to look at causing the toes to flip up slightly, and to an 18-millimeter reduction to a be weak in the flexor tendons. 2-millimeter­ increase with the PHCP distortions and keep in Hoof evaluation and care—within the trim). mind why they are first week of life—should begin with a ■ An overall 2.5-millimeter reduction minor trim, which the farrier should re- occurred in foot width (9.8-millimeter there and … try to peat every few weeks to help get the hoof reduction to a 5.8-millimeter increase) respect the lower limb.” surface completely on the ground. ■ Horses experiencing the most aggres- “That juvenile period is really important dr. scott morrison sive toe trimming had the greatest for the digital cushion and the collateral reduction in foot length, the smallest cartilages and all those things to respond increase in palmar foot length, a reduc- “An undesirable shape change is a to stress and develop and mature in a way tion in foot width, a 6-degree reduction distortion,” which can lead to discomfort so they are strong enough when they be- in heel angle, and no change in heel and , said Scott Morrison, DVM, come adults and athletes,” said Morrison, width. of Rood & Riddle Equine Hospital, in emphasizing the importance of getting the Take-Home Message Hampson empha- Lexington, Kentucky. proper proportions on the foal’s foot. sized that good hoof trimming isn’t purely Morrison explained that hoof capsule Morrison said he often sees changes a science. distortion can have many causes: in the hoof capsule after a few months, “Instead, it should be based on a ■ Most commonly, conformation faults; as foals start to toe out naturally. But the combination of measurement ‘guides’ ■ Injuries; capsule will become more symmetrical ph o t os Cour es y D r. Sc tt Morr i son Newborn foals often have weak flexor tendons (right) and contracted, underrun heels (left) that correct naturally with age.

TheHorse.com The Horse 5 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE again as the foal ages. He advised farriers body), especially the coffin joint and the to evaluate foal feet carefully and observe navicular structures located at the back how foals walk. When horses are young, of the foot. Morrison emphasized that farriery can help manipulate conforma- farriers need to understand the front half tion for the better, at least until growth of the foot’s role in establishing trac- plates ossify (harden into bone), he said. tion and supporting various inner hoof If a growing foal’s limbs become too structures. crooked, Morrison intervenes with shoe- Morrison likes to simulate the barefoot ing, using an extension to help straighten condition as much as possible in adults, the limb by shifting the foot’s center as well, to minimize the effects of shoe- of pressure. (This is the point at which ing. He said farriers should be able to the GRF acts upon the hoof.) He uses a draw a line where the coffin bone is and pour-in pad to help support the sole to then trim to the widest part of the foot, mimic the barefoot condition as much as which is usually the center of rotation. possible. Two-thirds of the coffin bone should be Morrison said any outward limb rota- in front of the center of rotation and one-

tion will usually self-correct as the foal Cour t es y D r. Sc o tt Morr i son third behind. grows into a yearling and his chest wid- Farriers might use heel plate shoes to rehabili- He also recommended trimming the ens. “It’s normal for the foot to be loaded tate severely compromised heel structures. foot to create a positive palmar angle, a little bit more medially than laterally, ideally 2-5 degrees, which he considers resulting in the medial wall being more Shoeing and Trimming Basics The way within normal range. The center of rota- vertical or straighter than the lateral the hoof interacts with the ground tion should line up with the geometric wall,” he said. impacts the whole limb (even the entire center of the weight-bearing surface of

Moisture, Temperature, Ground Conditions. Environmental Factors Affecting the Foot. Moisture softens the foot allowing for excess exfoliation, increased chances of thrush, foot expansion, and over hydration leading to abscesses. Extreme cold or heat slows hoof wall growth. Sole bruising and hoof wall chipping occur on hard, rocky terrain, and sandy terrain wears away sole.

Apply pour-in pads as a barrier to protect the foot from the elements.

1.800.483.8832 | [email protected] VA.0317.THORENVI Vettec • Orange, California • 1.800.483.8832 • www.vettec.com | EU Customer Care • +420 800 260 001 • www.vettec.net

TheHorse.com The Horse 6 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE the shoe. The ground surface of the heel should line up with the widest part of the frog, and there should be an adequate Handling Caudal Hoof Problems amount of sole depth, which varies based While many farriers might focus on the front half of the horse’s foot—specifically the on the size of the horse’s hoof. Ideally, toe—the caudal aspects (back half) also require careful attention. however, it should equal the width of the That’s because the back half of the foot can fail in many ways, said renowned per- horn lamellar zone. formance horse farrier Danvers Child, CJF, of Lafayette, Indiana. And how to identify and Morrison said the appropriate location manage such problems has been a topic of debate among farriers. of a horse’s breakover point—the forward- The Misunderstood Caudal Aspect “We often neglect the palmar or the plantar most point of the foot or shoe’s ground aspect of the foot,” Child said. contact—is hotly debated. He suggested Farriers have many ways to describe this part of the hoof: “50/50 ratios, widest part it be at the apex of the coffin bone, unless of the foot, center of rotation, however you want to talk about it,” he said. “We’ve got a he is treating a horse with problems. dividing line there, and I think that’s where we’re talking about the front half and the Supporting Compromised Hooves If a back half in our daily work and in our daily conversations.” horse’s hoof capsule starts to distort due Often, when the hoof fails, it fails in the back half of the foot, he said, listing col- to imbalances, Morrison said he favors lapsed heels, underrun heels, quarter cracks, heel cracks, and bar cracks as problems removing shoes when possible and letting that can occur in the caudal area. the frog hit the ground, which stimulates Looking for (and Preventing) Trouble When evaluating a horse’s foot, Child said hoof growth. he looks for distinctions between the bony attachment in the front half of the foot and For horses with stressed feet that need the cartilaginous attachment in the back half. There, based on the tubules’ (formed by axial (inner hoof wall) support, Morrison the stratum externum and stratum medium layers that extend from the coronary groove suggested various shoe types, heel plates, toward the bearing surface) appearance, he can usually see where a quarter crack or other problem will develop before it starts. pour-in sole supports, or pads or de- “You can take any foot and find where your quarter crack will be,” said Child. “That is creasing shoe thickness to allow the frog influenced radically by the position of the fetlock, conformation of the pastern, and by ground contact. how much we trim and set our ratios and proportions. It is also influenced by the place- He said the most popular way to pro- ment of our appliances (shoes, etc.).” vide support is with a straight bar shoe, Meanwhile, the bars on the bottom of the hoof provide an indication of the quarter’s which puts weight on the base of the frog health, he said. and, thus, unloads the heels. Additional The Fix If the bar bends, said Child, the hoof wall develops a commiserate bend options include an egg bar shoe, which is (or a flare). In his work with a group of Purdue University broodmares, on which he per- designed to provide limb support; a heart formed four trimmings, he found it more effective to eliminate flares and distortions by bar, which has a “V” shape useful for addressing the foot’s solar aspect by working on the bar instead of the hoof wall itself. supporting the frog while allowing thrush “If I’m addressing that wall, I’m just aesthetically improving that flare; I’m not ad- treatment; or a short heart bar, which is dressing the flare,” he said. “But if I go in and I manicure that bar, then I’m … actually safer for speed horses. addressing the structural component. I’m trying to move that base of support back to Pour-in pads provide support by allow- where I think it belongs and to where those anatomical structures tell me it belongs.” ing the horse to weight his whole sole. A Child cautioned that it might take several trims to remedy the problem completely. frog cradle is a safe way to support the Quarter cracks don’t have to develop for a problem to need fixing. Child said he deals base of the frog, he said. Farriers often with many broken heels, crushed heels, and structural failures that don’t progress to use stabilizer plates on racehorses, but quarter cracks. When a horse’s heels break down, many farriers turn to a heart bar shoe they can sometimes be difficult to clean to correct it, he said. In contrast, he offers bar support by applying a rigid pour-in pad. out and can bruise the hoof bars (the Short Schedules, Healthy Feet Finally, Child said, in his more than 35 years of inward folds of the hoof wall, located on practicing farriery, he’s had to rehabilitate more feet of horses on eight-week trimming either side of the frog). and/or shoeing schedules than on six-week schedules. “The more you can shorten that schedule … the less that foot is going to distort,” he said.— Sarah Evers Conrad Very compromised hooves are sore everywhere, making it difficult for farriers to provide any support, said Morrison. In these cases he applies a heel plate shoe Managing Severe White Line Disease the lamellar apparatus to the point that with some dental impression putty and White line disease is a bit of a misno- the horse develops laminitis. rolls the toe and the heel to make the mer as it doesn’t actually affect the white Mike Steward, DVM, APF, of Shawnee, horse more comfortable. line along the bottom of the hoof wall. Oklahoma, described the intricacies of “You have to look at distortions and Rather, it’s a disease process that sets up treating and shoeing horses with severe keep in mind why they are there and … within the inner nonpigmented section of white line disease. try to respect the lower limb,” said Mor- the hoof wall, called the stratum medium, Diagnosis One of the big challenges rison. “In trying to change hoof capsule that can also erode into the stratum inter- in treating white line disease is that its distortions, you also want to think about num (where the sensitive laminae attach cause is unknown. The disease process how you are going to change the mechan- the hoof wall to the coffin bone). In se- usually begins with separation of the ics of the whole lower limb.” vere cases, white line disease can damage hoof wall’s insensitive laminae from the

TheHorse.com The Horse 7 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE underlying sensitive laminae attached to anaerobic bacteria (which thrive without material, place it within the defect for the coffin bone. Bacteria, fungi, and dirt oxygen) that could be degrading the hoof support, and wrap the foot with a cast. can then enter the space and cause infec- wall. It also helps reduce stresses on the He added that some farriers also apply tion, which is often difficult to treat due diseased hoof wall that are causing the super glue to the cleaned lesions’ edges to to its location and the lack of blood flow separation. He emphasized the impor- help seal them and prevent more damage. to this area. tance of cutting away the entire infected Steward stressed the importance of Veterinarians typically diagnose white stabilizing the hoof wall and coffin bone. line disease by looking for abnormal wall If possible, he trims and rolls the affected separation or wall conformation, tapping The toe soreness can toe and might then use a wedge pad or the hoof wall to listen for a hollow sound, clog pads to help take some of the load and applying hoof testers to the sole. A be a result of the white off the diseased area. These wedging and veterinarian or farrier can use a hoof line disease’s damage to breakover modifications can help reduce knife to cut away the diseased part of the pressure on the deep digital flexor ten- hoof wall to get a better idea of the extent the lamellar apparatus, don, which is attached to the coffin bone, of infection and separation. However, he resulting in laminitis.” to help prevent (or relieve pain associated said, radiography is a useful and less- with) laminitis. Sometimes he applies invasive diagnostic tool. dr. mike steward ethylene-vinyl acetate (memory foam) to Treatment Though it can take some help lessen concussive forces on the foot, time, treatment is relatively simple, said area. Then he said he usually applies a especially if the horse will be walking on Steward. When dealing with these cases, topical medication to treat the infection. hard ground or concrete. he removes the dead hoof wall with a If the hoof wall defect is particularly Shoeing Farriers use various shoeing hoof knife, Dremel tool, or half-round large, Steward said he might mix pow- methods, depending on their knowledge nippers. This allows oxygen to reach dered copper sulfate with impression of shoe mechanics and the individual

CAUDAL HEEL

Cause Uneven loading of foot. Improper heel and toe placement. Effect Narrowing of heels and frogs, improper toe landing and lameness. Solution Trim to proper heel and toe ratio. Increase weight bearing surface of the foot by moving heels back and support the sole with a pour-in pad. Result Heel and toe ratio is in balance and the sole is supported. The heels are returned to their normal position and lameness is averted.

Vettec • Oxnard, California • 1.800.483.8832 • www.vettec.com

Utrecht, The Netherlands • +(31) 30 241 1823 • www.vettec.net VA.0416.THORCADL

TheHorse.com The Horse 8 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE

change in the hoof capsule’s shape every time it’s loaded with the horse’s weight) and underrun heels. They compared the degree of deformation in hooves with and without underrun heels and evaluated the effects of carbon composite hoof wall patches on underrun heels. Regardless of the term used—underrun heels; long-toe, low-heel; slung heels; or collapsed heels—this issue appears to oc- cur more frequently in the front feet than the hind. For this reason, Day focused his research on only the front hooves. He said he considers heels to be underrun or collapsed when the heel angle is lower than the toe angle by about five degrees. Underrun heels develop as the toe grows too long and the heels appear to grow forward rather than downward, becoming lower. This changes the forces acting on the foot’s structures—especially the deep digital flexor tendon that inserts on the coffin bone—making the navicular bone

ER IC A L ARSON more vulnerable to injury. White line is a disease process that sets up within the inner nonpigmented section of the hoof wall Horses can be genetically predisposed and can erode into the stratum internum, where the laminae attach the hoof wall to the coffin bone. to a low-heeled foot, so breeders should take this into consideration to avoid foot’s needs. For example, said Steward, ­Steward recommended using a “taller” perpetuating the problem. Wear and tear they might apply a wide web shoe, a pad, shoe to move the breakover point back. on the predisposed hoof over time causes and sole impression material to redistrib- He cautioned that horses wearing tall the horn tubules to bend and the heels to ute the horse’s weight to the back of the shoes should be confined to spaces where lower. This affects hoof deformation and foot and protect the painful toe area. they can’t move at speed, which can blood supply to the foot. “The toe soreness can be a result of the increase pressure and forces on the collat- Day described two theories behind white line disease’s damage to the lamel- eral ligaments and possibly cause injury. hoof deformation: lar apparatus, resulting in laminitis,” said Steward concluded that while farriers 1. Compression of the frog and the sole Steward. have many shoes to choose from when puts pressure on the foot’s cartilages Some of his favorite shoes for stabiliz- treating white line disease, they should and pushes them upward, causing the ing the hoof and redistributing weight select the one that meets the individual hoof to expand. include heart bars, egg bars, square-toed horse’s mechanical needs. The goal is 2. Forces going through the hoof wall’s shoes, and full roller motion shoes. In to stabilize and protect the hoof and laminar attachment are redirected more severe cases, he might use a clog enhance healing. as the middle phalanx (short pastern similar in design to that of the “outlaw bone) lowers during the stance phase, shoe” for horses with laminitis. The Relationship Between Hoof pushing the hoof wall and the cartilage “The concept of the wooden shoe (such Deformation and Underrun Heels outward. as the eponymous Steward Clog) is utiliz- Horse owners, veterinarians, and Day’s team performed a series of four ing mechanics in an orthotic (an artificial farriers alike know that preventing hoof research projects using cadaver limbs as support) to alter the hoof’s engineering problems is better than having to fix well as live horses. They tested different to enhance healing,” he said. “Stability them. But when a hoof problem, such as hypotheses revolving around carbon com- and mobility are uniquely balanced in underrun heels, does develop, it’s impor- posite patches’ effects on hooves. Results such a manner they allow the hoof to tant for your horse’s health care team to indicated that carbon composite patches function in an optimum manner when be up-to-date on the latest research and applied to the hoof wall in horses with normal. Altering one of these entities will treatment methods. collapsed heels can improve horn tubule inversely affect the other, and these are Peter Day, Dipl. WCF, farrier at the strength, circulation, and hoof deforma- just two of many things that need to be Royal Veterinary College, in Hertford- tion and shock absorption, offering farri- considered when altering mechanics to shire, U.K., and colleagues conducted ers a practical application for preventing enhance healing of white line or other a series of studies looking at the rela- or treating collapsed heels. hoof pathologies.”­ tionship between hoof deformation (a Day performed his last trial in 12 front If the foot requires more mobility, shock-absorbing mechanism—the natural cadaver legs to determine whether hoof

TheHorse.com The Horse 9 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE deformation differed between horses ­encouraged farriers to ask owners about with or without collapsed heels when the footing the horse is living and work- artificially loaded at the equivalent of a ing on. “Sometimes a particular shoe on fast trot. He found that overall deforma- a particular terrain might be exactly what tion and foot spread was greater in feet you want,” said Day. without collapsed heels. In feet with “At the moment, there is a lot of collapsed heels, the medial heel showed (research) going on in pads and packers significantly more proximodistal (from and the effects they’re having,” he added. the inside outward) deformation. This “A lot of that early work was done in the confirmed their hypothesis that feet with laboratory on cadaver material.” He says collapsed heels have less heel deforma- the preliminary results are exciting. tion and, thus, reduced shock absorption, Because this abnormal hoof conforma- which can cause further foot problems. tion ultimately contributes to a range Treating the Problem Farriers’ support of foot problems, such as navicular and treatment options for underrun heels syndrome, chronic heel pain, bruising, include: coffin joint pain, lameness, and reduced ■ Buttressing the heels Al exandra Be ck s t e tt performance, Day encouraged farriers to Underrun heels can lead to a number of foot ■ Raising the heels problems, including navicular disease, chronic take control of the way a horse is shod. ■ A natural balance or barefoot trim heel pain, bruising, coffin joint pain, and more. He advised keeping the horse on a set ■ Broad shoe trimming and shoeing schedule, despite ■ Heart bar shoe ■ Cuff cast any owner resistance, so they can try to ■ Egg bar shoe Treatment method often depends prevent problems rather than end up hav- ■ Packers and pads on the horse’s environment, so he ing to fix them.

Before

Cause Over paring, wet environment causing over exfoliation, abrasive terrain.

Effect Sensitivity to hard ground, sole bruising, thinning of the hoof wall, flattening of the sole.

Solution Apply pour-in pad material to minimize exfoliation and provide protection. After

Result Sole has time to regenerate itself and increase depth eliminating sole bruising and potentially resulting in thicker hoof wall.

1.800.483.8832 | [email protected] Vettec • Orange, California • 1.800.483.8832 • www.vettec.com VA.1016.THORSOLE EU Customer Care • +(31) 30 241 1823 • www.vettec.net

TheHorse.com The Horse 10 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE

Physiology, Foot Morphology, and Health in Przewalski’s Horses Researchers study feral and wild horses for a variety of reasons. For instance, they evaluate hoof health to better understand hoof conformation, disease, and lameness in domestic horses. Information gathered about hoof angles, wall thickness, lami- nitis incidents, and more all offer insight into keeping horses sound. Hampson presented a study in which he looked at foot morphology and foot health in one herd of Przewalski’s horses. A History of Domestication Hampson began with a summary of the history of horses as different genetic branches sepa- rated into domestic horse breeds and wild horses, such as the Przewalski’s horse and the Tarpan. He also clarified that what we often think of as “wild horses,” such as mustangs and the Australian , aren’t really wild; they’re feral. Horses were domesticated about 5,500 years ago, said Hampson, and were ini- tially used for milk and meat. Research- ers estimate humans started riding horses around 3,000 years ago.

At least 87 breeds have already gone I S T O CK.C M extinct, Hampson said, and 25% of the re- Dr. Brian Hampson was surprised to find laminitis in Przewalski’s horses and hypothesized that all maining 900-plus breeds are endangered. equids are vulnerable to this disease. Additionally, he said, modern horses don’t have as much genetic diversity and compare it to what researchers know ­millimeters, similar to that found in as previous wild and ancient domestic about those of domestic and feral horses, brumbies and domestic horses; populations.­ Hampson studied the feet and blood work ■ Three of the 20 had mild chronic lami- What We’ve Learned From Przewalski’s of 12 stallions and eight mares from the nitis but could walk; Horses In the 1960s, the Przewalski’s herd, aged 2 and 13 years. He collected ■ Nine of the 20 horses had “normal” horse, which originated in Mongolia, radiographs, photographs, lamellar his- feet; came back from near extinction. Current tology (samples for microscopic exam), ■ Of the 10 horses’ tissue samples, five numbers hover near 2,000 worldwide, and serum insulin concentrations. showed changes normally associated thanks to careful breeding of 16 captive He and his team found several dif- with hyperinsulinemia (a condition in horses in the 1970s. ferences in hoof shape and structure which there is excess insulin circulating The Przewalski herd that Hampson between Przewalski’s horse and feral/ in the blood relative to glucose); and studied lives on Europe’s largest steppe domestic horses: ■ Ten of the horses had low insulin levels area, in Hungary. Researchers collect data ■ The dorsal hoof wall angle was around (two of those were laminitic). on these horses, such as heart rate, body 57°, compared to brumbies at 55°; Hampson also shared that Lane Wal- temperature, movement, grazing habits, ■ The heel angle was 42°, compared to lett, DVM, a veterinarian and paleon- diet, and location. brumbies at 45°; tologist at the University of Florida, in During the winter, researchers have ■ The coronary band angle (you guessed Gainesville, studied equine fossils up to learned, the herd goes into a torpor— it … the angle the coronary band forms 3.5 million years old and discovered a their heart rates drop by 50%, body with the ground) was 21°, which is the 75% incidence of chronic laminitis (see temperature by up to six degrees, and same as brumbies. TheHorse.com/33506). body mass by 20%. The herd stands for ■ The palmar angle of the distal pha- Take-Home Message Based on these long periods, eating only one-third of lanx was 6.3°, whereas it was 5.7° in findings, Hampson hypothesized all hors- their usual diet. The hooves are long brumbies;­ es are vulnerable to laminitis. Diet and and overgrown during this time and are ■ The sinker distance was 7.7 millime- lack of exercise might be contributing fac- trimmed naturally through movement ters, compared to 6 millimeters in tors to the disease, he said, but there are come spring. small domestic horse breeds; likely other unknown factors at play. To learn more about the horses’ hooves ■ The hoof wall thickness was 14.6 “We were really surprised to find

TheHorse.com The Horse 11 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE laminitis in the Przewalski’s horse,” he said. “We thought there might have been something­ that was different about that horse’s foot that protected it from laminitis. We thought that most likely we’ve changed the foot of the domestic horse over the last couple hundred years that has made it susceptible to laminitis, but that doesn’t seem to be the case. It’s always been there. Feral and wild horses aren’t exempt to these pathologies.”

What Does Shoe Wear Reveal? Farriers and veterinarians came together in several Summit roundtable discussions to compare their experiences and offer advice to their peers. In one packed session, farriers discussed shoe wear, what it indicates about the horse, and what can slow it down. In addition, attendees reviewed how riding discipline and certain health conditions might impact shoe wear. Adam Wynbrandt, APF, vice president

of the American Association of Profes- I S T O CK.C M sional Farriers/International Association Factors that affect shoe wear include footing, conformation, way of going, shoe material, and more. of Professional Farriers, moderated the session and said he’s personally seen shoe other riders now riding the horse? These of information. He added that higher-­ wear patterns herald upcoming health factors could cause horseshoes to start density synthetic shoes wear quicker. problems. He told the audience that as wearing differently than normal. Horse Factors Regarding horses that they gain more knowledge, they can tell One attendee noted that if, historically, show shoe wear changes, the farriers de- more about the horse based on shoe a horse has shown a wear pattern on one scribed how laminitic horses that recover wear. side of his shoes but then this stops, it or have had a recent setback might have Factors affecting shoe wear run the could indicate that the owner might have unusual wear. gamut and can include: changed something with the horse. They talked about the differences ■ Arena footing or turnout surface; Another farrier said a horse he was among disciplines, such as how endur- ■ Shoe material; shoeing had medial (toward the midline ance horses wear shoes down very ■ Conformation and way of going; of the body) toe wear. It turns out the quickly and could need a reset after just ■ Ongoing medical problems; horse had hock problems, and once the one race. One solution for excessive wear veterinarian injected those joints, the is to use borium. medial toe wear pattern went away. One farrier suggested adding weight What Lies Beneath Farriers also dis- to the shoe to reduce wear, because the Endurance horses wear cussed how footing affects shoe wear. For horse will pick his feet up higher. shoes down very quickly example, if a horse is ridden in an arena Often horses that are not engaging with newly added heavy sand, then steel their hindquarters or conditioned for and might need a reset shoes might start to show increased wear. the type of work they are doing wear after just one race On the other hand, many agreed that shoes faster. On the other hand, chopped rubber footing is one of the easi- horses, which must engage their hind- est surfaces on shoes. quarters during work, tend to wear down Another change that can cause a shift their hind shoes faster and might need ■ Shoe tightness; and in shoe wear patterns is addition of stone those shoes reset more often than horses ■ Saddle fit, among others. dust or a similar material to a field or in other disciplines. Subtle Shifts? It’s important for the paddock to help deal with mud issues. One Standardbred racehorse farrier farrier to ask the horse owner what he The abrasive surface wears a shoe down noted that he would trim a horse’s foot or she is doing with the horse and if faster than normal terrain would. down on the side of increased wear anything has changed. For example, One farrier who favors using synthetic- because the horse was clearly off balance, have there been changes in the horse’s material shoes said they wear similar to but then occasionally he would trim the or rider’s weight or rider’s skill level? Are a steel shoe and provide the same type opposite side more to move the hoof’s

TheHorse.com The Horse 12 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE center of force to the medial branch. Regarding Standardbreds, farriers noted that pacers tend to wear down the Farriers: Consider More Than Feet When inside of the hind feet while trotters wear Trimming and Shoeing down the outside. If any horse is wearing hard on the Farriers need to observe every horse thoroughly and gather as much information as pos- toe, one farrier said rocker-toed shoes sible to determine how to trim and shoe that horse, said farrier consultant, clinician, and might be a good option to apply. Another author Michael J. Wildenstein, CJF, APF, FWCF (Hons.) of Cynthiana, Kentucky. agreed, adding that he sees this with trail Wildenstein described how to assess the horse as a whole before shoeing. horses and puts them in concave shoes. As farriers observe hundreds—even thousands—of horses throughout their careers, they These give horses more purchase, which learn to use all their senses. Evaluations begin with viewing the entire horse. “It’s not what you look at. It’s what you see,” said Wildenstein, who calls farriery a combination of science helps prevent excessive wear. and art. Take-Home Message Regardless of the Farriers should assess angles and take measurements before running their hands breed or discipline the farriers serve, they over the horse. They’ll look for muscle issues, lift the limbs in the normal range of motion, agreed that it’s important to record shoe and feel joint mobility. They should also talk with the owner about any recent changes in wear in their notes because it’s difficult the horses’ condition or routine (including environment, weight, condition, or tack and to remember. Monitoring shoe wear and equipment) or changes in the rider’s weight, skill, or techniques. The farrier’s job is to use changes over time is a key way farriers information they gather to develop a care plan for the horse. learn about their clients’ horses. Wildenstein described the importance of examining the hoof capsule, which can reveal important information about what’s going on with the horse’s body and limbs and How Uneven Feet Affect a Horse what stresses are being placed on the hoof, along with possible pathologies (disease or in Motion damage). Additionally, hoof and shoe distortions and wear provide farriers with valuable It comes as no surprise that when a information about the horse. horse’s feet aren’t even, neither are the Farriers also must understand all the limb deviations—that is, departures from ideal forces placed on those important struc- conformation and alignment—that can occur and how they affect the horse. tures. But exactly what effects does this “Deviations affect the entire animal and are reflected in the hoof,” Wildenstein said. “A have? horse can have multiple deviations in the same hoof. That hoof is a road map of what is A team of European researchers recent- going on above. You can see those (spatial) differences if you take the time to look.” ly investigated whether unevenness influ- Rotational deviations, which involve the limb or hoof turning inward or outward as ences loading patterns during movement viewed from the front or back of the horse, can affect hoof shape, movement, and break- and whether foot conformation or the over patterns. If a horse has a rotational deviation, it’s important for the farrier to stand in difference between feet is more important the direction of the rotation so they can look only at the angular component. in limb loading. Sarah Jane Hobbs, PhD, Farriers also need to evaluate the horse in motion. With today’s technology, farriers can use smartphones to record video and apps to slow footage so they can review it frame by the research lead in equine biomechanics frame. at the University of Central Lancashire, in When the farrier finds a deviation, he or she should ask the following questions: England, presented her team’s study re- ■ Is it an acquired deviation? sults. She worked alongside Willem Back, ■ Is it new, or has it been there for a long time? DVM, PhD, Dipl. ECVS, Cert. KNWvD, ■ What can we do to help the horse? Spec. KNMvD, and his students from Limb deviations, which can occur in long bones as well as in joints, can result from con- Utrecht University, in the Netherlands, formation problems, movement issues, riding methods, body imbalances, muscle atrophy, and Sandra Nauwelaerts, PhD, from the and more. University of Antwerp, in Belgium, on the Beyond watching and touching the horse, the farrier can use his or her sense of smell; project. distinctive odors can often reveal whether a horse has an abscess or a fungal infection. In previous studies, equine researchers Wildenstein, who worked for more than 20 years at a veterinary school, feels that just as found connections between uneven feet important as completing a thorough assessment is working closely with veterinarians and and pain avoidance as well as postural owners as a team. and loading preferences in standing He stressed that farriers can help the horse over the course of his life to perform better horses. In one study of elite performance and for longer while improving comfort level. “You want to leave those horses better off horses, researchers revealed that animals than when you came,” he said.—Sarah Evers Conrad with uneven feet typically retired earlier than those with even feet. In Hobbs’ study, her team evaluated 34 shod and unshod horses that came to measure­ differences­ between left and (50-55 degrees), or upright (more than 55 into the clinic for routine examinations. right hoof wall angles in the front feet. degrees). Thirteen of the horses had even feet, They classified horses with a difference The researchers set up infrared three- while 21 had uneven feet. The team in hoof angle of more than 1.5 degrees dimensional motion analysis cameras for used proximal and distal (top and bot- as having uneven feet. They also labeled gait analysis along a corridor lined with tom) markers on the dorsal hoof wall feet as flat (less than 50 degrees), medium rubber mats placed over a force platform.

TheHorse.com The Horse 13 2017 International Hoof-Care Summit Coverage SPONSORED BY

HOOF CARE

They also placed a cluster of markers along each horse’s cannon bone and long pastern bone and on various points along the hooves to collect kinematic data, which they analyzed with 3-D software. Handlers trotted the horses down the corridor so the researchers could evaluate forces at the ground and lower limb movement.­ The team also measured the following conformational parameters to see which were better predictors of foot unevenness: 1. Hoof area; 2. Hoof width; Hobbs’ team evaluated ground forces and lower limb movement 3. Heel height (unloaded); as horses trotted over a force platform. 4. Hoof angle; 5. Long pastern length; the vertical force was greater in the limb

6. Long pastern inclination; with the flatter foot compared to the c our t es y dr. sara h jane o bb s 7. Cannon bone length; and limb with the steeper foot. The fetlock Researchers have found connections between 8. Fetlock angle. sunk lowest before the force reached its uneven feet and pain avoidance as well as pos- tural and loading preferences in standing horses. Findings The team found that, of maximum. these parameters, hoof angle was the After this, the horse starts to rise up best predictor of uneven feet, followed and push forward, and the point where the timing of the force measurements by unloaded heel height. Hoof width the horse stops braking and starts push- relate to how big those forces are and was not a good predictor of uneven feet, ing forward happened later in the limb where they are acting on the limb and Hobbs said. They also determined that with the flat foot. This was not because body while the foot is on the ground. So, the difference in hoof angle between the the flatter foot was on the ground longer in the flatter-footed limb the force vector two front feet had a greater effect on than the steeper foot, Hobbs said; both (the invisible arrow coming out of the the results than the hoof angle of each hooves spent the same amount of time on ground that describes the total force and individual foot. the ground. its direction) is greater and points more Because the fetlock sinks more with toward the tail for a longer time, which the flatter foot and before the vertical suggests the rear of the limb is loaded Hoof angle was the force reaches its maximum, the limb longer during each step. As the force vec- is less stiff during loading. This cor- tor moves toward the nose (as the limb best predictor of responds to the ‘mechanical lameness’ goes from braking to pushing) there is uneven feet, followed that veterinarians describe at the walk, less time on the ground for this to hap- where the flatter foot’s fetlock joint visibly pen, so pushing forward and breakover by unloaded heel sinks more. Because we can’t see this in occur quicker in this limb. The opposite height.” the trot, researchers have suggested that occurs in the limb with the steeper foot. the condition is not associated with pain These differences load the limb’s internal dr. sarah jane hobbs or pathology (disease). Hobbs’ measure- structures differently, which is likely to ments, however, suggest this might not be influence the integrity of the hoof and When comparing front feet measure- the case. The difference was not visible, limb tissues and also exacerbate changes ments in the uneven horses, Hobbs but the alteration in stiffness and the dif- in foot shape. discovered several differences in move- ference in maximum force might indicate Take-Home Message Horses with ment patterns and forces produced at that underlying pathologies do exist. uneven feet experience different loading the ground: In the limb with the flatter Researchers should be able to confirm patterns during locomotion, which might foot, braking force produced when the this in future studies. be partly responsible for changes in foot hoof was in contact with the ground was The fact that the hooves were in shape along with habitual asymmetrical greater than braking force in the limb contact with the ground for the same standing postures. It’s important to moni- with the steeper foot. In the middle of the amount of time was not surprising to the tor these horses’ hooves, as asymmetrical stride, when the body sinks to its lowest investigators, as they graded the horses feet could lead to lameness and possibly point, the fetlock joint sunk lower and as sound at the trot. The differences in early retirement. H

TheHorse.com The Horse 14