Hoof Cracks, Wounds, and More Discussed at Farrier Session (AAEP 2010)
"No foot, no horse" is perhaps the most used and still the most true statement there is in horse care. A horse is generally worthless without functional feet, which is why the American Association of Equine Practitioners devoted a complete day during the 2010 convention (held Dec. 4-8 in Baltimore, Md.) to farriery topics and the working relationship between veterinarians and farriers.
"Heat adds strength to any relationship; this is the perfect metaphor for this discussion," said Jay Merriam, DVM, of Massachusetts Equine Clinic, in Uxbridge, in his presentation on veterinarian/farrier working relationships, titled "Sharing the Fire."
"Vets can't do it all alone, and neither can farriers," he said. "Vets can add podiatry to their practices, and farriers can add veterinary consultation to theirs. There are things we just shouldn't do alone."
Topics discussed during this year's farriery program included basic foot anatomy/examination, hoof crack repair, supporting the heels, puncture wounds of the hoof, foot surgery, and more.
Before you can treat problems in the foot, you have to know its proper anatomy and function. Andy Parks, MA, VetMB, MRCVS, Dipl. ACVS, department head and professor of large animal surgery at the University of Georgia, discussed examination of the foot for the audience with numerous images from the Glass Horse anatomy program.
"Why are you looking at the foot?" he asked the attendees. "Because something's wrong with it or it's a purchase exam. Presenting symptoms can include abnormalities in form (misshapen) or function (lameness).
"Most things that affect the foot are trauma or infection," he went on. "The foot shows you where excess stresses are, and specific diagnosis leads you to specific treatment. Predisposition to disease leads to preventive care. Indicators of abnormal stress lead to symptomatic treatment."
Parks expanded upon several guidelines for examining the foot, including the following:
- First, do the free/easy diagnostic techniques (such as visual examination, using hoof testers, etc.);
- Record a thorough case history;
- Look at the whole horse first to assess his stance and body condition, and evaluate the environment he's living in; and
- Then do a basic foot examination, followed by an examination of the foot relative to the limb, a more detailed examination of hoof characteristics, evaluation of the limb in motion, and evaluation of the shoeing and/or trim.
Cleaning the foot is essential to a good exam (a good wire brush is very helpful).
Hoof Crack Repair
"Hoof cracks are a common problem and can affect any part of the foot, causing variable lameness," began Kent Carter, DVM, MS, a professor of equine lameness at Texas A&M University. "Some are devastating and cost millions in lost revenue, while others are insignificant. Recognizing the difference will help us all."
The key to fixing a quarter crack is not the patch, screws, or plates put across it, he said. Rather, healing and getting rid of a quarter crack for good depends on proper trimming/shoeing to correct the foot imbalance that caused the crack. Without fixing that imbalance, cracks will often return even if they are successfully repaired in the short term.
He discussed the pros and cons of several hoof crack repair strategies and products, ending with this summary: "Proper trim of the foot is essential, therapeutic shoeing is important, and stabilization of the crack (with wires, staples, patches, etc.) is not always necessary but it is beneficial if performance is desired. Exposed soft tissue may become problematic (if it's not dried out well before covering it with a patch); don't create more problems."
He also briefly discussed hoof cracks and separations caused by white line disease, an opportunistic fungal infection of the hoof. Removing any detached wall is essential, he noted, as this loose wall isn't doing any good. This also makes it much easier to treat problems underneath the separated wall.
Hoof Puncture Wounds
If your horse picks up a nail or other sharp object in his foot, one of the first questions many of us have is whether to remove that nail immediately or wait until the veterinarian can see it. Rich Redding, DVM, MS, Dipl. ACVS, associate professor of equine surgery at North Carolina State University, recommended leaving the foreign body in if at all possible until the veterinarian can take radiographs (often called X rays) to see how deep the wound is and what structures might be affected.
"If you can't leave the foreign body in place, mark the site (so it can be found for later examination)," he recommended.
Redding discussed several types and aspects of foot wounds in horses, along with reviewing additional strategies for evaluating such wounds including contrast fistulography (injecting contrast material into the wound and taking a radiograph to see how deep the wound is), physical exploration of the wound with thin, blunt metal probes, ultrasound, thermography (examination of heat patterns), and MRI.
Lastly, Redding discussed several options and technique tips for treating these wounds, which often require some degree of surgical debridement (opening up the wound tract so it can drain and be medicated). Additional treatment strategies include thorough cleaning of the wounds, antibiotic treatment (both systemic and regional might be indicated), wound protection with waterproof bandaging, and lavage (flushing) of any compromised joints.
Hoof Biomechanical Research
"I'd like to introduce a third person to the hoof care team, so we have veterinarians, farriers, and research scientists," began Jeffrey Thomason, MSc, PhD, an anatomy professor at the University of Guelph''s Ontario Veterinary College, in Canada. "Biomechanical research is helping us elucidate the exact causes of many injuries, which is leading to better diagnoses, treatments, and prevention."
He went on to discuss the basic biomechanical properties of the horse, including the heavier body compared to thin, light legs that can be moved quickly for great speed. "The horse uses his own weight very effectively," he observed.
However, there are trade-offs to this structure--for example, long, light bones give more speed and stamina, but this also means a higher risk of fracture. Long tendons and ligaments act as energy-storing springs, but those long springs are at risk of mechanical injury.
Thomason went on to describe several types of biomechanical research strategies, from direct measurements to calculated ones in live horses, to in vitro studies with cadaver limbs.
"Biomechanics researchers, veterinarians, and farriers can all meet in the middle for applicable interpretation of research information," he concluded. "Everyone should communicate well so researchers understand the problems faced 'on the ground,' and can devise studies that take that into account."
Saving the Heels
"I see thin walls in so many breeds," began well-known racehorse farrier Ian McKinlay of South Amboy, N.J., whose practice focuses mainly on repairing hoof cracks and other foot problems. "Pliable, thin walls often cause the heels to collapse under the horse's own weight," and pain and lameness in the palmar (rear) part of the foot are the all too common results.
McKinlay discussed a number of factors contributing to low heels in his clients' horses, from poor trimming to short shoes to too many baths/foot soaks. He also demonstrated his methods for trimming the foot, sizing the shoe (often using a longer one than the horse was wearing), rebuilding the heels as needed with hoof repair composites, and using a special dual-material rim pad under glued-on shoes to cushion the heels.
This pad, which is much like the ones McKinlay put on Triple Crown hopeful Big Brown, includes a hard rim under the front half of the foot and a softer rim in the rear part of the foot to cushion the heels. Also, a cut-down channel around the inner edge of the pad shoe can hold a rubber strip or dam to keep the glue from getting on the sole and applying pressure there with weight bearing.
McKinlay reported success with more than 100 cases of palmar foot pain (mostly in racehorses) treated in this manner in a six-month period.
"The advantage of the method described in this report is that the procedure has a strong bond (to the hoof) with a minimal amount of adhesive, zero sole pressure, and total support of the heel while being relatively simple and easy to learn," he concluded. However, he cautioned that inappropriate trimming, shoe selection, and shoe placement will negate the benefits of the pad.
After reviewing various methods of gluing horseshoes onto hooves, Derek Poupard, CJF, Dipl. WCF, of the United Arab Emirates, described a novel method for building a horseshoe directly on the horse's foot using a hoof repair composite injected into a silicone mold wrapped around the foot.
Sound confusing? It's a bit like putting on a glove that's a little too big for your hand and squirting a composite into the glove to build you a new, completely tailored glove that fits just right.
"It''s like baking," he commented with a smile. "You put icing into a little mold and you've created something."
This method of shoe creation is quick and easy, noted Poupard, and yields a protective covering that functions much like the natural hoof in terms of expansion/contraction. It's also easy to rasp to reshape as needed once cured. However, it's not inexpensive, doesn't stand up to quite as much wear as a metal shoe, is harder to maintain in a wet climate, and yields a raised heel that necessitates some sole support to maintain frog pressure.
"This method is just another tool we can use," he concluded.
Sport Horse Farriery
Sport horses place great demands on their feet, as they're often "maintained at a competition-readiness condition year-round," began Duncan Peters, DVM, MS, of Hagyard Equine Medical Institute in Lexington, Ky. "This means that from a fitness level and foot-care standpoint, these horses are always in a high-maintenance situation."
It's key to maintain good communication between owner, trainer, veterinarian, and farrier to optimize soundness in such horses, he noted. Sometimes those people will disagree on the best approach for the horse and, thus, "There needs to be open discussion and ultimately, collaborative decision-making," he added.
Peters noted several challenges when managing sport horse feet (such as little to no turnout time, high demands of competition, and too-frequent baths and wetting of the feet). He also offered several tips on keeping them sound, such as trimming/resetting every 4-5 weeks to keep feet in top shape, providing proper breakover in the front half of the foot, supporting the heels, maintaining proper mediolateral (inside to outside) balance, providing good breakover to the sides of the foot as well as the toe, aligning the bones of the leg for optimal soundness, and protecting the bottom of the foot.
"Foot care of the sport horse requires all involved to be attentive to the functional needs of the horse and any changes in performance that may occur related to the feet," he concluded.
- "You often need to surgically invade the foot to treat infection, benign tumors (keratomas), penetrating wounds, and lacerations," began Clifford Honnas, DVM, Dipl. ACVS, of the Texas Equine Hospital in Bryan. He described a number of conditions he treats with surgery as follows, as well as the critical aftercare provided by a farrier to help the horse recover.
- Removal of a sequestrum (diseased, isolated piece of bone) that's often due to infection from a puncture wound. The fragment is removed as well as any dead tissue, and the area is medicated and protected for healing. These usually do very well, Honnas noted.
- Keratomas, or benign soft tissue masses that develop between the hoof wall and the coffin bone, might result from chronic inflammation. These are removed through as small of an opening as possible, and the prognosis is "excellent," said Honnas.
- Infection/necrosis (tissue death) of the collateral cartilage can occur from various wounds or traumas, and cause lameness as abscesses form, he explained. Removal of the infected/dead tissue under general anesthesia is the recommended treatment, and the prognosis is good provided all the dead tissue is removed.
- White line disease can result in a significant amount of hoof wall detaching from the underlying structures, and removal of this loose wall allows access to medicate affected areas and removes the ground reaction force on the loose wall. This helps the remaining healthy wall grow down tight to the inner structures of the foot.
Abscesses beneath the sole are "probably the most frequent condition affecting the foot of the horse for which invasion of the hoof capsule is required," Honnas noted. Abscesses can cause severe pain, but opening these abscesses up surgically to allow drainage and medication provides effective treatment.
"Surgery of the foot is a very common occurrence; one thing we can't emphasize enough is that it necessitates a good team approach (between veterinarian and farrier)," Honnas concluded.
About the Author
Christy West has a BS in Equine Science from the University of Kentucky, and an MS in Agricultural Journalism from the University of Wisconsin-Madison.
POLL: Radiographs for Hoof Care