Hoofcare Education at Bluegrass Laminitis Symposium
One of the most common comments at the 15th annual Bluegrass Laminitis Symposium in Louisville, Ky., Jan. 21-23, 2002, was that if farriers or veterinarians don't have a passion for working on laminitic horses, they shouldn't take the cases. Horse owners know that a laminitic horse is a high-maintenance case in terms of treatment and convalescent care, but perhaps we don't always think of just how much commitment is involved on a day-to-day basis.
Repeatedly, speakers urged those interested in focusing on laminitic horses to aggressively seek out learning opportunities from those who specialize in this problem. Our understanding of this devastating disease is constantly evolving, with new treatments or new applications of common treatments being proven effective. Therefore, only a devotee of education in this area is likely to keep up with all of the new ideas.
This symposium is well known for presenting the latest in laminitis research and practice, and this year was no different. However, practice was the biggest part of many presentations this year, with several consisting almost entirely of case-by-case analysis with video and slides to document the progress of specific horses. Many speakers discussed their successes in treating laminitis cases very aggressively, while others focused on the diagnostic process.
Whatever the focus, the common thread was that you must learn as much as possible about the process and treatment of laminitis and other severe hoof problems in order to defeat them.
Diagnosing and Classifying
Bruce Lyle, DVM, a primary care equine veterinarian in Aubrey, Texas, discussed important concerns and signs for diagnosing lameness, illustrating his points with photos and videos of several types of cases. "Today we have many more options to successfully treat and rehabilitate the lame or injured horse, but they also provide the temptation (and the ability) to eliminate the gait deficit and return the horse to activity before the tissue is adequately healed," he began. "This exacerbates tissue insult and creates the chronic conditions often described in popular texts. I am very concerned with preventing an acute insult from becoming a chronic pain."
He described several tell-tale signs of damage to or imbalance of particular regions of the foot, and the results of his treatment protocols. "I hope to make you aware that there is more to foot lameness than navicular disease, founder, wall cracks, and abscesses," he added. "In spite of the seemingly effortless grace with which these animals perform, there are some incredible forces at work, and horses get injured. Early identification and intervention prevents minor injuries from becoming chronic pains."
Ric Redden, DVM, the owner of the International Equine Podiatry Center in Versailles, Ky., and the recognized laminitis expert who hosts the symposium, addressed the classification of laminitic damage once the diagnosis is made (his scale runs from 1-1,000).
"Seldom, if ever, do two horses have the same degree of damage, and seldom are feet affected the same on one horse even when the same mechanics and therapeutic regime were used," he explained. "Just simply designing a detailed plan to reverse the forces at play is all but a shot in the dark without first assessing the damage and identifying the precise areas compromised."
He discussed various aspects of hoof pathology and described his protocol for evaluating each one, aided by case studies. "Using a meaningful grading system also helps me be more focused on many aspects of the syndrome that I otherwise may overlook," he commented.
"Pulling a handful of films from the processor, hoping a few of them are good enough and knowing full well that most will not be diagnostic, is not only frustrating but a tremendous financial black hole for all concerned," said Redden. His talk on developing a useful radiographic protocol for analyzing the equine foot consisted mainly of videotaped radiographic procedures at his clinic, followed by in-depth analysis of X rays from various angles. He discussed each radiograph in terms of how well it was taken and how well different angles showed particular structures.
X rays aren't the only important part of a diagnosis, however: "The history and a thorough exam are far more important than any radiograph," he commented. "The radiograph is just for confirming a diagnosis."
(Redden offered several tips for taking useful radiographs of the equine foot. For a complete list of these, see article Quick Find #2769 at www.TheHorse.com.)
He also described a venogram technique (which involves injecting radio-opaque dye into a blood vessel just above the hoof to allow visualization of blood flow in the foot) using video to emphasize the short time available for getting a useful image.
"You only have about 30-45 seconds to take the film with the venogram--you have to be quick and have everything ready," he said.
Tips for the venogram procedure included making sure to get the tourniquet tight enough and rocking the heel upward briefly to allow perfusion of the anterior portion of the foot.
Septic osteitis (SO, inflammation of bone beginning in the periosteum or membrane surrounding bone) of the third phalanx or coffin bone can be a problematic complication of laminitis. SO has historically been regarded as a problem that called for an extremely guarded prognosis or even euthanasia, but Lyle has a different take on it.
"The horse will be very painful on the infected foot," he explained, "and after the foot is derotated and balanced, he'll fail to improve despite maximum mechanics (mechanical shoeing correction), antibiotics, and pain medication. In very critical cases, the horse's respiratory pattern and behavior might be similar to a horse with anoxic or septic abdominal crisis (flaring nostrils, heavy sweating)."
On radiographs, Lyle said that in the horse with SO, one might see progressive thickening of the horn-lamellar zone (distance between the laminae and the outside of the hoof wall, which is not exclusive to SO), loss of sole depth in the affected area, asymmetric collapse of the proximal hoof wall into the coronary band of the affected area (unless it was recently trimmed and balanced), and a gas density adjacent to the bone.
Digital venography has been the most helpful tool for deciding if surgery is indicated for treatment, he said. "The tissue's not going to live without blood supply," he explained. "We have to do venograms so we can see if there is any blood to the area.
"Large areas of bone not encased by the corium's vascular web should be removed," Lyle continued. "Smaller suspicious areas can be surgically approached, and if bone is exposed, it can be curetted or treated locally and observed."
Following surgical treatment, the area is packed with dimethyl sulfoxide (DMSO)-soaked sponges and amikacin (or hydrogen peroxide).
"The bottom line is that SO is curable," Lyle concluded. (For more on Lyle's presentation, see article Quick Find #2771 at www.TheHorse.com.)
Value of Digital Venograms
A recent 10-horse study by Lyle evaluated the use of digital venography to enhance a practitioner's ability to reasonably predict the course of laminitis early on, to stimulate thought for new treatments, and to evaluate a horse's response to treatment.
Lyle made two important points regarding the diagnostic use of venograms in his presentation: First, that diagnostic procedures such as venography should be used to confirm or rule out a diagnosis based on physical examination and history (such procedures should not be considered diagnostic by themselves). Second, a diagnostic procedure such as a venogram should only be performed if its outcome could change the treatment plan for the case.
"The venogram has tremendous potential to do this, placing us in a position to be proactive rather than reactive in non-compensated (unhealed) cases," Lyle said.
Based on his findings, Lyle suggested that venograms can be used to evaluate which of the three distinct vascular plexuses associated with the coffin bone might be compromised. Identification of the exact area(s) affected could lead to more exact medical and mechanical treatments. As a side note, many veterinarians and farriers have reported an improvement in circulation and healing following digital venograms. (For more on Lyle's presentation, see article Quick Find #3269 at www.TheHorse.com.)
Navicular Syndrome Diagnosis
Earl Gaughan, DVM, of Kansas State University's College of Veterinary Medicine, discussed the many considerations in diagnosing the cause of heel lameness, focusing primarily on identifying navicular syndrome.
"Navicular disease is very difficult to study because you can't reproduce it in a normal horse," he said. "You can't then work backward from the disease to find a cure. The pathogenesis for navicular syndrome remains unproven, but there are some common trends."
He said the commonalities include:
- Small hooves relative to body size;
- Work with a torsional component (twisting forces on limbs);
- Unbalanced hooves; and
- Irregularly scheduled farrier care.
"Navicular" horses tend to have several common threads in their histories, including an apparent acute onset of lameness (often following a period of indeterminate poor performance), which can mimic proximal (high in the limb) lameness when viewed from the saddle that worsens with stops and turns and seems to shift from the left to the right forelimb (and vice versa). These horses also have a characteristically choppy stride, which results from the horse trying to land toe first or flat (instead of the normal heel first sequence).
Gaughan encouraged practitioners to ask owners about the horse's previous work during a diagnostic exam. This, he said, can have an additive effect on the horse's feet along with his current work. Medication history and any changes in the horse's athletic expectations are also important.
Diagnostic tests include blocking of various structures to evaluate the specific structure(s) that is painful, X rays to evaluate bone structures and joints (to rule out bone spurs, etc.), scintigraphy to evaluate bone and soft tissue inflammation, ultrasonography, and thermography.
Treatment might include trimming, shoeing, medical therapy, and/or surgery for particularly difficult cases. The prognosis for a navicular horse is variable, as the disease tends to be progressive, said Gaughan. Success depends on the duration of the case and response to treatment; some horses can be weaned off of treatment, while others can't.
"My opinion is that navicular syndrome is not as devastating as it was previously considered to be," he concluded. (For more on this presentation, see article Quick Find #3276 at www.TheHorse.com.)
Foot/Lower Leg Wounds
When a horse's hoof or leg is severely wounded, removing any foreign matter such as fence wire and applying antibiotics could make evaluation by your veterinarian more difficult, explained Gaughan in another talk. "The key to success is to see the wound as it happened, not covered with purple, green, blue, or whatever colored dressing or powder," he said.
He also encourages clients to leave any penetrating objects--such as nails or wire--in place so that the veterinarian can see first-hand and via X rays how deep and what structures the object involved (see "Puncture Wounds" at left). If transport is necessary, he suggested clipping off the object near the skin or sole, and wrapping the area in a bath towel to pad it before shipping the horse to a hospital. You can also tape pieces of wood thicker than the object to the sole of the foot to keep the horse from pressing the object deeper.
"Some of these wounds don't look like they go anywhere dangerous, but if you wait for the horse to tell you otherwise, then you might be behind and success might not be possible," Gaughan cautioned. Flushing compromised joints, preferably arthroscopically to visualize any debris that might need to be removed surgically, is important.
Thermography can be a valuable tool for assessing blood flow distal to the wound. If there is little to no blood flow beyond the wound (noted by cold, dark areas on the thermograph), then the prognosis is very guarded. Also, ultrasonography can help detect foreign material, gas pockets, and abnormal fluid accumulation in and around the wound.
In discussing treatment, Gaughan said, "It's vital to maintain good hygiene--usually clean and covered is the way to go, but my advice is to back off of any topical medications initially." He also said that it is important to support tissues that can heal, especially in cases where movement delays healing. He warns against covering hoof wounds with acrylics, citing a risk for abscess formation due to the moisture in the wound.
"The prognosis for these horses varies depending on what structures were injured, but often patience (during the often lengthy healing process) is rewarded," he concluded. (For more on this presentation, see article Quick Find #3280 at www.TheHorse.com.)
There are always plenty of farriers in attendance at this symposium, and they appreciate presentations on shoeing tips. The first of these was presented by Micheal L. Steward, DVM, of Shawnee, Okla. He discussed the manufacture and fitting of wooden shoes (with a curved ground surface) for laminitis cases in which money is often an issue. While some attendees dismissed his technique--which involved shaping a three-quarter-inch plywood block to the desired form, adding cushion support, then attaching it with deck screws while the horse stands on the block--others viewed it with appreciation for his ingenuity.
Farrier Danny Dunson discussed evaluating cases with a veterinarian's input and balancing the foot rotationally (correcting imbalance from a previously rotated shoe) as well as mediolaterally. In addition, American Farrier's Association Certified Farrier Bernard Pelletier presented shoeing methods for the high-scale damage laminitis case using heart bar shoes with frog cushion and the breakover moved back.
"Since we developed our team approach, podiatry cases are now enjoyable for us," he explained. "The prescribed therapy, prognosis, and expected cost is now much more predictable." Wooten also recommended the use of a sling to support a very lame horse for shoeing rather than nerve blocking, saying that they had found this better for both horse and farrier.
The symposium concluded with the live shoeing demonstration. This year, venogram, diagnosis, and white line treatment techniques were featured as well as general shoeing methods.
With more education under their belts and more ideas to pursue in their practices, these farriers and veterinarians are better armed to battle devastating hoof problems.
NUTRITION AND HOOF GROWTH
Edgar A. Ott, PhD, of the Department of Animal Sciences at the University of Florida, presented a review of research (which he completed with E.L. Johnson, PhD, also of the University of Florida) that focused on nutritional effects on hoof growth. Following are their conclusions, based on 19 research sources:
- Nutritional factors that are required for growth of the animal might not have a positive effect on hoof growth and development;
- Rapid hoof growth and quality hoof growth might not be synonymous;
- Amino acid availability and those factors required for conversion of the amino acid methionine to cysteine are probably very important in hoof growth and development;
- Minerals such as calcium and zinc are critical for hoof growth and development;
- Proteinated trace minerals (those provided in proteinate form), zinc, manganese, and copper have a positive effect on hoof growth in young animals, but do not seem to influence hoof quality;
- Fat supplementation does not seem to influence hoof growth or quality; and
- Biotin can improve hoof quality in some horses, but not hoof growth rate.--Christy West
Manu Sebastian, DVM, MS, of the University of Kentucky's Livestock Disease Diagnostic Center, presented a study of laminitis cases submitted to the center for necropsy from 1995-1999. A total of 281 horses were part of this study, with 87 diagnosed with only laminitis and 194 with laminitis and other conditions. (See Article Quick Find #3313 at www.TheHorse.com for the study's detailed findings.)
"These findings suggest that the causes of laminitis or conditions associated with laminitis still remain elusive in many of the cases, which prevents us from developing a preventive strategy for this disease," he said.
Following the presentation, Ric Redden, DVM, was asked about preventing laminitis. "Obesity is the easiest thing in the world to prevent, but the the hardest to teach (owners to prevent)," he said. "It's harder to prevent than steroid/hormone problems."--Christy West
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: Equine Lameness Concerns