Computerizing the Hoof

"The biggest problem as I see it," quips Wendy Wergeles, 20-year trainer and event rider of Cottonwood Farm, Los Alamos, Calif., "is that horse owners and even novice competitors understand very little about their horses' feet. They hire a farrier to shoe their horses and hope the job got done well without really knowing how to evaluate whether it did or not."

How can farriers explain to owners what they are doing in an easy-to-understand, visual way? How can owners learn more on their own about that amazing structure of engineering, the equine hoof? How can a clear-cut record of the gradual changes in the hoof structure be tracked over time so that deviations that might be precursors to hoof problems can be caught before full-blown problems emerge?

Enter the age of high-tech communication. Software programs now are available that measure a digital image of a horse's hoof, outline edges and angles, and store the images and information for future review. Several programs were designed to measure any image (including NIH Image, Scion Image, and Image/J), but one of them (Metron, released in August 2000) was designed specifically for evaluating horses' hooves.

"Our intention in designing Metron was to establish a common dialogue in the form of standard parameters so that people can begin to study feet from the same reference points," says software developer Monique Craig of Eponatech, the software company that produces Metron.

"There seem to be quantitative differences in common expressions used to refer to the equine hoof, depending on the person's background," says software co-developer John Craig, her husband.

Say What?!?

An owner often will know basic hoof terminology. But just as often, as the jargon of trimming becomes specific to pathology or even deviations, the horse owner's eyes will begin to glaze over, signifying lack of comprehension. The farrier can attempt to explain the imbalance, yet frequently the owner's untrained eye is unable to perceive subtle differences. Even veterinarians, depending on their area of specialization, generally do not get the opportunity to spend time looking exclusively at thousands of feet over the course of their careers.

Common communication issues include confusion regarding orientation of the limb as well as technical terms versus common horse jargon. To an equine professional, the "palmar process of the coffin bone" is a clear location on the bone. When speaking to a lay person, the distinction becomes muddled when phrases like "the back of the bone" are substituted. Hence, the very nature of language can limit effective communication.

So, for farriers who deal with veterinarians regularly, technical terms are easy to remember. Farriers who interact more with horse owners tend to think in terms to which their clients can relate easily. Either way, the jargon they use might alienate either the veterinarian or the client depending on the person's frame of reference.

With Metron, the lingo is less of a problem because the information on a given horse can be called up as numeric data or as a photograph on which measurements are clearly marked. What makes the program so instructive is that it superimposes visual representations of measurements on top of photographs (and radiographs in the higher-priced version). This makes comparative differences immediately obvious. For the horse owner tracking her own horses, the terminology eventually will become self-evident in the process of using the software. Adding horses to the database requires an owner to pick out the areas for comparison according to the guidelines provided, giving each person an opportunity to develop an eye for feet and a head for terminology. Several programs also allow the owner to add text or other pictures, like a shot of the whole horse for identification, to keep more information on each horse.

Also, by allowing direct comparisons of the outside of the foot with the inside of the foot when radiographs are available, these programs reinforce the concept that the equine digit is a three-dimensional, dynamic structure that adapts to use, trimming, care, and neglect. This helps bring people past the two-dimensional view that hoof angles alone are the key to good shoeing.

Metron also allows farriers, veterinarians, and horse owners to e-mail measured photographs and radiographs from within the program, so that everyone is on the same page and can clearly see what might be a problem. A text file containing more detailed information on the horse in question can be created and associated with the hoof image file, and will be e-mailed along with the image. In the case of a foundered or laminitic horse, these communications can be critical because owners don't always know how to interpret what they see. Therefore, when time is of the essence, the communication becomes clearer and quicker.

Baseline Comparisons

For equine professionals who deal with pathology on a regular basis, or even for keeping records of normal feet, the ability to track hoof changes with digitally measured images taken at various times fulfills important diagnostic and tracking needs. (However, only Metron can store information and images in an integrated database.)

For example, some hunter-jumpers in a barn could be shod by a farrier who thinks that leaving the toes slightly longer gives them a greater surface area for landing. The others may be shod by a farrier who thinks that bringing the breakover farther back decreases the stress on their tendons.

To date, the only way to measure success is pretty subjective, as long as the horses aren't lame. Now you can quantify the gradual changes inside and outside the hoof capsule, so that even novice horse owners can understand which shoeing practices safeguard the long-term health of the equine digit.

Another advantage is that if the owner has baseline images of the horse's hooves taken before an injury or case of laminitis, the veterinarian or farrier quickly can determine and quantify what damage has been caused by the current in-jury or disease.

"The overall concept of using digital images to measure hoof balance and conformation is valid," says Albert J. Kane, DVM, MPVM, PhD, who has done several digital hoof measurement studies that looked at what measurements of hoof balance were important in preventing injury. "How we use those measurements still needs a lot of research, however. Digital image analysis can be a very useful tool for conformation research and evaluation of horses, but before we can apply it clinically, we need to get more data to see how to use it. We need to do more research and find out what measurements are most useful and what the typical baseline numbers should be. It's hard to use numbers from an individual horse without an accurate, reliable standard to measure them against."

Robert Bowker, VMD, PhD, a research scientist and associate professor in the Department of Veterinary Pathology at Michigan State University, currently is using Metron in his hoof studies at MSU. He says, "One problem is that we never see normal feet because no one ever has a complaint with them."

What's A Perfect Hoof?

None of these programs try to establish what constitutes optimal trimming and shoeing. That remains to be seen as the data piles up over the next few years. However, Metron does come with default guidelines, or rules, that are meant to be a reasonable facsimile of what constitutes a healthy foot. These default rules are fairly simple, and they are intended to apply to almost any basic foot (i.e., a healthy foot that isn't padded up like a Tennessee Walking Horse or cut down like a resected hoof). Metron can "score" each image according to its default rules, which determine that image's score based on exact measurements, ranges of measurements, or ratios of different measurements specified by the rules. When the rules are applied to an image, the image's measurements get a percentage score based on how closely they reflect the rules' measurements (adjusted for the horse's height, weight, and other basic values).

Again, these default guidelines might not be ideal for every horse; in fact, it's quite difficult to imagine that any set of measurements, even if breed-specific, could be considered ideal for the widely varied equine disciplines within each breed. This is why the Metron developers made sure the rules can be changed or new ones created.

"The frustrating thing is that to make this comparison feature really useful, the scoring needs to be explained in detail and the numbers need much more work and support by published research," says Kane.

"The concept of this software is terrific. It would be a great research tool. I just think it needs more work before it can be applied. If a proven scoring or grading system can be developed, it could be a very useful tool for preventing lameness or injury."

It almost seems like this feature could be more hassle than help unless one understands the standards used for comparison, such as comparison of one horse's measurements over time or in research applications.

For the farrier or veterinarian with specific ideas about how a foot should look, the guidelines in Metron can be modified to reflect that idea. Hence, the flexibility of the program is especially enticing for the research scientist involved in proving or disproving a given hypothesis concerning trimming, shoeing, or hoof health. The various measurements the program supports can be set to whatever values you like, or not used at all. These rules can be e-mailed or downloaded, and can be implemented in any copy of the program. Eventually, Eponatech plans to create rules based on several researchers' findings and provide them for download from the company's web site.

The current image also can be compared with the software's database of other images, which includes measurements for about 150 horses. Many of those measurements are from purchase exams on sound horses. Users of the software can compare a horse's measurements with the Metron database, their own database of horses, all horses in both databases, or not compare them at all. One can compare by breed (primary and secondary breed for crossbreds), age range, sex, height, shod or unshod status, soundness level, etc. The soundness is estimated by the user as the percentage of days the horse is sound.

Equipment Requirements

The equipment used to study equine hooves can be unwieldy, expensive, and highly technical. By contrast, these programs are easy to use, portable, and relatively inexpensive. The Metron software starts at under $150 for Metron-P, the photo-only version, but you can download a free trial copy of Metron at (Metron-PX has databases for both photos and radiographs, and costs a bit more.) NIH Image and Image/J are available free at, and Scion Image is available free at NIH Image is popular with researchers in many disciplines because of its freeware status; more high-powered image analysis programs often cost several thousand dollars.

Metron is available only for the PC platform, while NIH Image is designed for the Macintosh. Scion Image is available for either platform, and Image/J can run with any version of Internet Explorer over 4.0 and Netscape over 4.5. You need a camera to record images, of course; either a digital camera or a conventional camera will work. If you're using a conventional camera, you will need to get your photos on CD from the developer, or get a scanner to record the images digitally.

A digital camera makes it easier to organize your photographs and eliminates the need for a scanner. A relatively inexpensive digital camera costing about $200 is adequate unless you want to analyze radiographs, in which case you'd need to spend a bit more for a higher-resolution camera. For digitizing radiographs, you could use either a light box and digital camera or a scanner with a special attachment for transparencies.

More Features

Eponatech currently has a research database of about 1,000 horses and is adding to it daily. Eventually, as the database grows with the entries of trusted consumers (including veterinarians), the guidelines for good hoof conformation will be calculated based on averages derived from a wide variety of working horses, instead of from subjective opinion.

Updates for the database will be made available for downloading from the web site on a regular basis.

One consideration with the database feature is that Metron only stores the information. It lets individuals compare each image with the set guidelines or other horses as mentioned earlier, but in order to compare the measurements of several images (as is frequently the case in research applications), a separate program is needed that runs those types of calculations (a spreadsheet program). Craig is planning to add this type of broad comparative calculation ability in the future.

Photography Considerations

Ideally, hoof photographs for the database are taken when the horse is being shod, because measurements are more accurate if the horse is barefoot. An increment of measurement called a "scale marker" is included in the photograph to give the computer a reference for measurement. With radiographs, the measurements can be calibrated by entering the film focal distance in the pop-up panel on-screen. This is a distance that the person taking the radiograph knows. This method certainly is adequate for general use, whereas for research, the specifics can be further refined for enhanced accuracy.

A major consideration in using any image analysis program is how the photograph is set up. Measurement can be accurate only if the surface to be measured is perpendicular to the camera. "How you take the image is critical, and it can be difficult to achieve consistency on live horses," Kane says.

Another variable is that there always will be some subjectivity in the placement of the points or "picks" used to establish the measurements. However, as long as the user is consistent, there is a small enough margin for error that results still will be relevant.

Future Applications

These measurement programs could be used to prove or disprove theories about trimming and shoeing, and how differences in trimming and shoeing affect the overall health of the horse. "It's amazing how much people will believe about theories on horses' feet," Bowker says. "This software will help give substance to the things we really see.

"I think this software will be more useful for vets than owners," he continues. "Vets will be more able to compare changes in the horse's hooves between visits, as owners don't usually have access to radiographs. Also, more people are starting to demand more from the vet in terms of a diagnosis. There's more subtlety in the symptoms we see because more owners aren't waiting until their horses are three-legged lame.

"There isn't always consistency in the way vets take X rays as some don't always mark the apex of the frog, take them at slightly different angles, etc. I think vets will use them more for comparison with their own regional average values than anything else." Actually, most of the people who have purchased Metron are farriers and/or vets.

Obviously, conclusions only can be as accurate as the data entered. Hopefully, this will lead to a renewed level of consistency in the collection of data. For example, radiographs must be true lateral shots, or they will be subject to misinterpretation.

These software programs are not intended to be diagnostic tools, merely tools for measurement, tracking, and communication; hence, the diagnostics must be left up to the professionals. As with any versatile tools, they will only be as good as the skill of the person using them. For example, based on measurements and radiographs alone, it is impossible to tell whether or not a horse is sound. That probably is one of the mystifying things about horses that keeps professionals and owners intrigued.

About the Author

Gabrielle Pullen

Gabrielle Pullen, GCFP, NCMT, has been working professionally with horses and riders since 1994, enhancing mobility and performance using a variety of skilled modalities that address neuromuscular function. Her take on rehabilitation includes a broader paradigm than mechanically working on muscles as if they were inanimate objects. She focuses on fine-tuning awareness, building on the refinement of their existing highly sensitive consciousness to improve their movement and behavior.

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