Focus on Lameness
See what veterinarians and owners learned during the AAEP's late summer meeting on lameness.
Want to know what veterinarians talk about when they get together? This year it was lameness. Late each summer the American Association of Equine Practitioners (AAEP) hosts a seminar focusing on one particular aspect of equine health. The 2007 AAEP Focus meeting covered equine lameness. As a first this year, the AAEP also hosted an educational day for horse owners covering a variety of topics, including lameness and laminitis. There also was a Blue Ribbon panel discussion on the advances in and needs for equine lameness research.
Following you will find a brief synopsis of some of the talks presented at the Focus meeting; complete articles on each topic can be found on TheHorse.com. Additional articles not related to lameness presented at the horse owners' day also can be found online.
Current Trends and Approaches in Lameness Diagnosis
At the AAEP Blue Ribbon Panel Research meeting, Andy Bathe, MA, VetVMB, DEO, Dipl. ECVS, MRCVS, of Rossdale & Partners in the United Kingdom, spoke on improvements in technology to aid in lameness diagnosis. He said lameness is the most important cause of wastage in the equine industry.
Diagnostic techniques are often subjective based on practitioners' experience, and Bathe speculated whether gait analysis could become more objective in its application to lameness.
When using diagnostic nerve blocks, he said it is important to record findings and data as one progresses through the exam. With the advent of digital radiography, there is improvement in radiographic quality, but he expressed concern that technique is still the most important factor, and technique is dependent on veterinarian skill and understanding of the areas being imaged. However, digital ultrasound equipment is able to image more structures than ever before, so operator proficiency to acquire good images is not as crucial as in previous decades.
In reviewing other diagnostic tools, Bathe recommended nuclear scintigraphy as an excellent technique for identifying suspected fractures, but it should not be used as a "black box" to evaluate a low-grade lameness. Rather, the lameness should be worked up in a systematic manner with a thorough clinical exam, diagnostic nerve blocks, and radiology and/or ultrasound as appropriate. Any images obtained through high-tech equipment must be correlated with the horse's clinical presentation.
Bathe said magnetic resonance imaging (MRI) has revolutionized foot diagnostics; however, it is easy for images to be over-interpreted. He urged accurate localization of the pain-causing area first, then the significance of imaging studies is corroborated with the clinical exam.
Computed tomography (CT) scans are feasible in the standing horse for the head, but limb studies require general anesthesia.
Endoscopy requires general anesthesia and is indicated for persistent pain in synovial structures, such as joints or tendon sheaths.
Bathe examined three different approaches to lameness diagnostics:
Sequential Start at the bottom of the limb and work up with diagnostic nerve blocks, followed by imaging of localized areas of concern.
Targeted Pick the most likely location that could cause the lameness and pursue imaging diagnostics in that area
Survey Attack both ends of the horse from head, neck, forelimb, and pelvis, then perform diagnostic nerve blocks after imaging all areas
Bathe concluded that our understanding of lameness conditions has improved dramatically with improved imaging techniques, and we should implement advanced technology to improve our basic techniques. He stressed it is important to determine the significance of clinical presentation as it relates to imaging findings. The weakest link in workup is the interpretation of findings.
In the future, there might be opportunities for more genetic profiling to determine heritability of musculoskeletal disease. We continue to learn from MRI studies, and it would be beneficial to improve epidemiology by looking at our data that is readily available. In addition, more evidence-based medicine in diagnostics can be used to integrate clinical and objective data.
Recent Advances in Therapeutics, Part 1
Wayne McIlwraith, BVSc, PhD, FRCVS, DSc, DrMedVet (hc), Dipl. ACVS, Barbara Cox Anthony Chair and Director of Orthopaedic Research at Colorado State University, spoke on current and new therapeutic options to manage musculoskeletal injuries and osteoarthritis.
He reminded the veterinary audience that interleukin-1 (a deleterious cytokine) is at the head of the inflammatory cascade, leading to a breakdown in the cartilage matrix through signaling factors that alter regulation and effect of inflammatory biochemical mediators. The goals of therapeutic intervention focus on returning a joint to normal as quickly as possible, when possible, and to prevent the occurrence and severity of osteoarthritis in an injured joint.
McIlwraith discussed intervention that targets management of capsulitis (joint capsule inflammation) and synovitis (inflammation of the synovial membrane lining the joint; see page 55), since these tend to occur in advance of degenerative joint disease. One strategy that merits more investigation is physiotherapy, such as swimming or underwater treadmill therapy. This might be cutting-edge therapy, but more research and data is necessary to determine the extent of its value. One point McIlwraith made of great interest is the recent finding that two-thirds of the force across the carpus (knee) at the trot comes from muscle forces, rather than ground reaction forces as previously believed.
McIlwraith mentioned that extracorporeal shock wave therapy (ESWT) significantly reduces lameness and synovial fluid parameters as compared to control horses (those not receiving treatment) in the study; these findings support a pain and inflammatory mechanism of action that elicits lameness.
The clinicians in the panel discussion were also favorably impressed with the use of ESWT, particularly for injuries at a soft tissue and bone interface, such as in the distal (lower) joints of the hock and in the rear third of the heel associated with soft tissue trauma. Back pain was another suggested use of ESWT; however, it was felt if the back could readily be injected, there was no sense in spending the money on repeated shock wave treatments. One clinician said shock wave might be especially useful to apply to capsulitis and soft tissue damage in joints that are not amenable to intra-articular (IA) treatment.
The topic of non-steroidal anti- inflammatory drugs (NSAIDs) has been one of great interest to horse owners because of their value in managing pain and inflammation, yet the well-known adverse effects of gastric ulcer syndrome preclude long-term use of NSAIDs. There has been an in vitro study from some years ago suggesting that phenylbutazone might be injurious to joint cartilage, but McIlwraith noted there is no data or clinical evidence to support this claim in the live horse. With the introduction of a new cyclooxygenase-2 (COX-2, an enzyme that causes inflammation and pain) inhibitory drug (Equioxx) on the market, some information has come to light: If COX-2 mediators are completely suppressed, it is possible to get an up- regulation of interleukin-1, this being counterproductive to managing pain and inflammation. McIlwraith stressed that we should keep an open mind about the advantages of this newly released medication.
Another common joint therapy uses intra-articular (IA) steroid injections. McIlwraith revisited the pros and cons of various corticosteroid drugs, noting that not all of these are created equal in regard to how effective they are and their role in protecting the cartilage. The use of hyaluronic acid (HA) in conjunction with IA steroid treatment has been well-applied in the veterinary world for years. HA is no longer thought to have a primary function as a joint lubricant, since its anti- inflammatory effects are more important. One study mentioned by McIlwraith was that of improvement in lameness of horses injected only with 2 mL of sterile saline, the mechanism as yet undetermined. In moderate to severe cases of osteoarthritis, intra-articular therapy should include both steroids and HA.
Intravenous (IV) treatment with HA labeled for this use (Legend) has had marked favorable effects of decreasing synovial effusion in an injured joint, with therapeutic effects persisting for 44 days following the third weekly treatment. There is common usage of IV HA as a prophylactic medication in normal horses without lameness, and data thus far has not verified this to improve a horse's gait.
McIlwraith reported that oral HA seems to have some positive effect, with some ingredient remaining active in the molecule or fragment of the molecule after it passes through the intestinal tract.
Polysulfated glycosaminoglycans (PSGAGs) are considered to be "disease-modifying osteoarthritic drugs," and although they might be slow acting, they are cartilage modifying. Most of the favorable studies in using Adequan come from its intra-articular use. Studies on IM Adequan have given equivocal effects in one study, yet positive anecdotal reports abound.
A new product called pentosan polysulfate is soon to be licensed in the United States. This substance, made from beechwood hemicelluloses, seems to be a disease-modifying osteoarthritis drug, but it's without any pain-relieving activity such as seen with NSAIDs. Lameness is not improved, but progression of cartilage deterioration might be abated by correcting biologic imbalances in an osteoarthritic joint. Pentosan polysulfate exerts anabolic effects on cartilage precursor cells to decrease erosion of cartilage.
Oral supplements and nutraceuticals have been a hot topic in the horse world for some time. McIlwraith describes these as materials that are fed to heal the lame or make a chronically unsound horse become sound. They are used with the intention of preventing joint problems from occurring. However, McIlwraith points out that if a product is not licensed as a drug, then the manufacturer of such a food product cannot make medical claims as to its efficacy. There are no criteria for licensing these products, and, hence, there is often misrepresentation of advertising. In addition, there is no regulation to ensure the ingredients claimed by the label to be in the bucket are actually present in the bucket.
More specifically, McIlwraith discussed glucosamine salts that in theory are building blocks for articular cartilage. In one Virginia study, he said less than 6% of the material fed was actually bioabsorbed from the intestinal tract. In a Canadian study, following administration of glucosamine via stomach tube, very low levels showed up in the joints. McIlwraith said in one investigative report, fewer than a third of nutraceutical products contained less glucosamine in the container than what was listed on the label. In addition, he asked the audience, how do we even know the correct dose for a horse?
Chondroitin sulfate is absorbed well, but as McIlwraith pointed out, this does not prove effectiveness in the horse. Another study showed a joint-protective effect of a combination of glucosamine and chondroitin sulfate (Cosequin by Nutramax), but no anti-inflammatory effect. Other studies looked at the use of nutraceuticals on joint health, and either the studies did not have sufficient numbers of horses to be scientifically sound, or the data was flawed. When reading the results of studies, it is important to identify who is funding the study, since a company's vested interest could skew the results.
Some research has proven efficacy of the use of omega-3 fatty acids to inhibit enzymes that break down the cartilage matrix. In a three- to four-month period, horses supplemented with omega-3 fatty acids seemed to have less stiffness and pain related to osteoarthritis.
Finally, McIlwraith touched on the supplement with unsaponified avocado and soy, which is thought to somewhat decrease interleukin-1 levels and cartilage disease scores. This might be a useful product to add to a nutraceutical supplement, and more research should be pursued.
Recent Advances in Therapeutics, Part 2
David Frisbie, DVM, PhD, of the Gail Holmes Equine Orthopaedic Research Center at Colorado State University, continued the discussion on new therapeutics at the AAEP Focus meeting. He discussed the use of autologous conditioned serum (ACS), also known as Interleukin-1 receptor antagonist protein (IRAP). Whole blood is cultured with glass beads to upregulate interleukin-1. This material is injected directly back into a horse's ailing joint for a series of three injections, followed up at monthly intervals with another dose or two. In nonsurgical joints that are at least partially responsive to HA and steroids, IRAP treatment elicits less lameness and less synovitis up to 40 days following treatment.
Another therapy discussed by Frisbie was stem cells injected either directly into damaged tissue or peripherally (IV). There seems to be some trophic (nutritional) properties to the stem cells to increase mitotic (cell dividing) activity in surrounding cells and to recruit and mobilize other stem cells from other areas of the body to the injured tissue site. Currently there are two sources of stem cells: bone-marrow- derived or fat-derived. Bone marrow comes from an aspirate of a horse's sternum or ileum (hip bone), while adipose tissue is harvested from the fat of the tailhead or peritoneum (abdominal lining). The source from which these tissues are taken has an effect on the results, i.e., sternum-derived bone marrow gives better results than ileum-derived marrow. In addition, bone marrow stem cells are more effective than adipose-derived stem cells for treatment.
Recent studies in goats indicate that 50-75% of medial meniscal (inner stifle) injuries could regenerate. However, in horses the research indicates no decrease in lameness seen with stem cell treatment of equine osteoarthritic joints. Although there was some evidence of decrease in prostaglandins and inflammatory mediators, there was no reduction in cartilage erosion. In summary, Frisbie maintained there is no notable improvement in experimental osteoarthritic joints when treated with stem cells, but based on the goat studies, there could be potential value for helping soft tissue damage in an injured joint.
In a panel discussion about IRAP therapy, the clinicians all were favorably impressed in its use for chronic synovitis and capsulitis, especially for joints that one doesn't want to continually inject with corticosteroids, or following post- operative treatment with lingering inflammation. IRAP might have a use in horses faced with drug-testing deadlines related to Fédération Equestre Internationale (FEI, the international governing body for all Olympic equestrian disciplines) or other events. Another valuable use would be in managing medication of joints of obese or metabolically challenged horses due to concerns of steroids inducing laminitis in certain disease conditions.
Frisbie also discussed topical diclofenac cream (Surpass) as applied in a five-inch ribbon around an injured joint for three to four days. There was reduction in lameness with the use of this topical NSAID cream as compared to phenylbutazone-medicated horses and control horses receiving no treatment, but lameness was not statistically improved over controls. Although diclofenac cream improved the treated horses as compared to the nontreated and Bute-treated horses, there was little effect on joint fluid parameters. Frisbie feels that this product can be a disease-modifying osteoarthritic drug, especially when used with a solitary osteoarthritic lesion.
Diagnosis and Treatment of Stifle Lameness
Rick Mitchell, DVM, of Fairfield Equine Associates in Connecticut, spoke about stifle lameness. The stifle is a frequent source of lameness in English and Western performance horses, although it's not as common a cause as the hock. Stifle problems arise from chronic, repetitive trauma, or as a result of a pre-existing condition.
A horse with stifle pain often reduces the anterior phase (as the leg reaches forward) of the stride and seems to move on its toes. Upper limb flexion tests elicit lameness on trot-out that typically lasts for a longer period than what is seen following flexion for hock pain. Effusion of the stifle joint(s) is sometimes present. Any other number of clinical signs might be demonstrated, including poor performance. The jumping horse might preferentially seek out one side of a jump, typically jumping away from the pain in a drifting fashion. He might swap leads while on course. And there could be recurrent gluteal or back pain in a stifle-sore horse.
Riding the horse might exacerbate the lameness, and it is helpful to observe the horse when the rider changes the posting diagonal at the trot. Canter cadence might be altered when the affected leg is on the outside of the circle. Common stifle conditions include osteochondritis dissecans (OCD) lesions; subchondral cysts in young, developing horses and in older horses with persistent bone microtrauma; upward fixation of the patella; meniscal damage; cruciate and anterior ligament damage; and chondromalacia (softening of the articular cartilage) due to chronic repetitive trauma. Radiographic views are essential to identify some of these conditions. Ultrasound is helpful to assess soft tissue and early bone responses.
Typical treatment of upward fixation is the use of anti-inflammatory medications (NSAIDs), hand walking followed by a conservative rehabilitation program, therapeutic shoeing, and sometimes an internal blister is necessary to manage a recurrent and persistent case. Whether you're dealing with a mild or more severe case, physical therapy exercise should include long periods of low-intensity work and hill work to strengthen the quadriceps muscles. Some practitioners have had success with intramuscular estrone (related to the estrogen estradiol) injections for its anabolic effect on increasing muscle tone, particularly in geldings. A surgical procedure of splitting of the medial patellar ligament might induce thickening and stretching of the ligament.
Management of stifle synovitis and arthritis is similar to therapies suggested for hock lameness--IA steroids, IA hyaluronic acid, systemic anti-inflammatory medications, systemic joint therapy, arthroscopy, shock wave therapy, and acupuncture.
Diagnosis and Treatment of Hock Lameness
Jerry Black, DVM, of Pioneer Equine Hospital in Oakdale, Calif., discussed hock lameness. He said the cutting horse serves as a perfect model for the discussion of hock lameness, noting that no other discipline places more stress and torque on the hocks than what these horses experience.
Inflammation of the lower rows of hock joints is referred to as distal tarsitis, and it is associated with a variety of clinical signs. According to Black, an affected horse might demonstrate a "stiff" gait, especially noticeable when offloaded from a horse trailer. The horse tends to improve with warm up, yet a cutting horse in work might be reluctant to stop or properly hold the stop. There is a premature release of the caudal (toward the tail) phase of the stride in a horse with distal tarsitis (hock inflamation), resulting in a shortened cranial phase of the stride. This occurs as the horse feels shearing forces in the affected joints as he starts the push phase of the stride. Pain causes him to quickly release forward movement of the limb, resulting in a "stabbing" gait. Usually trotting the horse in circles will amplify the degree of lameness.
There are many causes of distal hock tarsitis, including incomplete or delayed ossification (mineralization) of the ends of the long bones of the joints, with concurrent osteochondrosis. Black feels there is a genetic influence; this is based on his findings of significant radiographic changes visible in 55% of 25 yearlings of the same cutting horse bloodline.
Other causes of tarsitis are related to traumatic injury from occupational use or due to degenerative problems that lead to osteoarthritis. Black says other factors can lead to distal hock disease, such as structural tendencies toward sickle hocks, cow hocks, and/or post-legged conformation.
Black urges the practitioner to perform a very thorough clinical exam that includes observation of the horse in a straight line trot, thorough palpation of the entire leg as well as the thoracolumbar region of the back, and flexion tests. It is important to do a hoof tester exam to identify or rule out any hoof problems. In addition to gait evaluation on the longe line or freely in the round pen, the horse might need to be ridden under saddle. All exams should be conducted on good footing.
Black stressed that a full radiographic series is important in tarsal evaluation. He notes that osteoarthritis typically starts in the distal intertarsal joint, with the tarsometatarsal joint affected next, and eventually osteoarthritis will advance into the proximal intertarsal joint due to biomechanical forces imposed on that joint. Other imaging techniques, such as ultrasound, nuclear scintigraphy, CT, and MRI, are valuable to define the extent of the lesions.
Black explained that treatment depends on the severity of the lameness and the level of pain. It also depends on radiographic findings, the age of the horse, its use, and the time of year the problem is being addressed.
Treatment goals focus on alleviating pain with effective and long-term results to protect the health of the joint while also allowing the horse to perform its intended use. The gold standard of treatment still relies on IA injection--it is efficacious and cost- effective. Use of systemic joint therapy is most useful when administered as a series of IV hyaluronic acid or intramuscular PSGAGs (Adequan), or as a combination. Black notes that while many sport horses cannot compete with non-steroidal anti-inflammatories in their systems, Western performance horses can, with these medications useful in managing tarsitis.
For horses that don't respond well to conventional IA anti-inflammatory treatment, IRAP therapy is effective in quickly decreasing inflammation. Shock wave therapy has been used with good results on tarsitis.
Therapeutic shoeing is essential to remove excess toe at the dorsal hoof wall and/or sole, and to provide adequate heel support with extended branches of the shoe and/or a wedged bar pad. The shoe should be square-toed or deeply rockered to ease hoof breakover. In addition, management and training changes must be implemented for treatment success: The horse should be given increased free-choice exercise, longer warm-ups, and when possible, training in deep surfaces and overtraining should be avoided.
Sue Dyson, VetMB, PhD, FRCVS, head of clinical orthopedics at the Animal Health Trust in Newmarket, England, discussed a variety of lesions in the carpal region of the nonracehorse. She prefaced her presentation by saying lesions in this area can be quite challenging to identify.
One common injury is that of the superficial digital flexor tendon (SDFT), usually in older competition horses aged 12-15 years. She noted that an abnormality is not always found on palpation or related to thickening of the tendon. Making this syndrome even more frustrating is that the lameness might be exacerbated by work, but it could only be intermittent in occurrence, with prompt resolution after rest. Often the lesions are bilateral (in both forelimbs) despite lameness only appearing in one limb. These SDFT injuries near the carpus do not do well with conservative treatment--either the lameness persists or improves only to relapse. It is possible this might be a degenerative lesion seen only in teenage horses.
Another lesion of the SDFT in the carpal or proximal metacarpal (hock) region occurs in the 15- to 20-year-old horse, with a sudden onset of severe lameness. These are degenerative lesions that are accompanied by pronounced swelling in the carpal canal region. These horses do not respond well to therapy, and Dyson reports they will stay lame. Cutting of the carpal retinaculum (the structure that holds the tendon in place) only provides a very slight relief.
Tearing of the SDFT at the junction of the tendon muscle is another syndrome that Dyson reports has a poor prognosis with no chance of recovery.
Surgical Treatments of Carpus Problems
McIlwraith discussed chip fractures and fragmentation in the carpal joint, which are the end result of a chronic process with associated difficulty in returning a horse to normal athletics. This is a common condition of racehorses. Usually, this is a result of repetitive damage and microtrauma to the bone. Severe lameness is evidence of major damage, although there is a poor correlation between clinical and radiographic signs. As soon as a chip fragment occurs, surgery should be done to ward off progressive damage that would occur if the horse continues to perform and race. Although this is a chronic process, it can be helped with surgery to normalize the inside of the joint and to minimize osteoarthritis. McIlwraith stated that arthroscopy is a gold-standard tool for both diagnosis and surgical treatment of the carpal joints.
McIlwraith described OCD lesions of the carpus and mentioned that the prognosis is not very good, particularly in a racehorse when OCD is likely of traumatic etiology; usually the horse experiences ongoing osteoarthritis despite treatment. The affected carpus is distended from synovitis and the horse is lame; flexion of the carpus exacerbates the lameness. Subchondral bone cysts also occur in the carpus in the distal radius (the end of the forearm bone closest to the ground), and have a more favorable prognosis with treatment depending on location and duration. Both OCD and cystic lesions can be approached with arthroscopic surgery.
McIlwraith stressed that post-operative management strategies, such as bandaging, anti-inflammatory medications, and physical therapy (walking, swimming, or underwater treadmill use) are critical to surgical success of carpal injuries.
Gait Analysis: Rehabilitation
Hilary Clayton, BVMS, PhD, MRCVS, Mary Anne McPhail Dressage Chair in Equine Sports Medicine at Michigan State University, presented her findings on investigation of rehabilitation techniques. She said although lameness is resolved in many sport horses, a horse is not always fully functional and still requires rehabilitation. Movement limitations are often due to tissue contraction and soft tissue injury as well as a need for relearning musculoskeletal patterns and restoration of joint movement.
Clayton's study was designed to measure the effects of tactile stimulation of the pastern region during the swing phase of a stride. Range of motion is greater in the swing phase than in the stance phase, giving the potential for a horse to display increased "action." The study measured the flight arc of the hoof, which represents the end result of all the joint flexions in the limb and work done by the muscles. The tactile device used was a lightweight strap with tiny chains, with a total weight of 55 grams, and this "stimulator" was attached loosely to the pastern. The small chains contacted the pastern, coronary band, hoof, and heel bulbs.
The results indicated that the height of the toe flight arc doubled with stimulators on the front pasterns, and it increased three-fold with stimulators on the hinds, with even more exaggeration than seen with front stimulators. The conclusion was that stimulators on any end of the horse give increased height in all feet, and that the elbow and carpus or stifle and hock are the main contributors to increased height of the hoof arc. The pastern is a particularly sensitive area, with the potential to affect rehabilitation techniques to return a horse to full function, or to improve athletic performance in sound horses.
Helping Foot Pain
Michael Schramme, DVM, CertE, PhD, Dipl. ECVS, of North Carolina State University, discussed analgesia of the tendon sheath and its significance to digital flexor tendon pain in the foot. The researchers concluded that analgesia of the digital flexor tendon sheath has little effect on lameness caused by pain originating in the sole, coffin joint, or navicular bursa. Anesthesia in the digital flexor tendon sheath limits pain only to structures within the sheath, such as the flexor tendon or distal sesamoidean ligaments. This study suggests that analgesia of the digital sheath is a useful alternative diagnostic tool for identifying tendonitis in the foot instead of relying on more expensive MRI.
Proximal Suspensory Ligament Disease of the Forelimb
Dyson also spoke on proximal suspensory ligament disease (PSD). She said PSD is common in horses from all disciplines, but is seen particularly in dressage and event horses. In many cases, the lameness might be sudden in onset, but seemingly resolves in 24 hours, only to reoccur when the horse is put back into hard work. Soft going makes the lameness more noticeable, especially when the injured leg is on the outside of the circle. Slightly intense speed at the trot makes the lameness more apparent. In working up the horse on evaluation, it is not uncommon to find that hock flexion amplifies the lameness.
Quantification of Ground Reaction Forces
Paul René van Weeren, DVM, PhD, Dipl. ECFS, an associate professor in the Department of Equine Sciences at Utrecht University in the Netherlands, discussed evaluating ground reaction forces to determine how a horse's limbs interact with its environment. Van Weeren's study confirmed that there is a useful correlation between calculated and measured individual limb forces using ground force plates to identify changes in limb loading in a lame horse. This technique is also valuable for gait analysis under any condition by eliminating the need for specialized hardware, wiring, or any conditions that influence a horse's gait.
Risk Factors for Catastrophic Fractures
Ellen Singer, DVM, DVSc, Dipl. ACVS and ECVS, MRCVS (epidemiology), of the University of Liverpool, discussed identifying risk factors that contribute to fatal distal limb fractures in the racing horse. The most common fracture sites include the lateral condyle of the cannon bone, the long pastern (proximal phalanx or P1) bone, and the sesamoid bones in the fetlock. Singer stressed that horses must be trained at speed if expected to race at speed. Singer recommends that future investigation should concentrate on lateral condylar cannon bone fractures and P1 fracture as these have the greatest impact on the industry. It is of value to investigate training methods and the relationship of fractures to canter/gallop ratios, as well as the relationship of racing to training. Recording of accurate training information could be improved with the use of GPS to log distance and speed.
Researching Complementary Therapies
Kevin Haussler, DC, PhD, assistant professor at Colorado State University, said the effectiveness of complementary medicine has been debated for years, and little research has been done to support it--a record he feels needs to be rectified. Haussler said veterinarians and horse owners need to overhaul their concepts of equine physical therapy. "The basis for rehabilitation today is when the horse no longer shows any pain or lameness, we stop," explained Haussler. "I think that gives us a lot of room for improvement." He said veterinarians and owners need to evaluate the horse's behavioral changes, flexibility of the joint, soft tissue, and strength of that area as a part of the rehabilitation process. "My challenge to the veterinary community is to move away from only evaluating pain and lameness, and let's get into some of the other things that affect the musculoskeletal system (such as range of motion, tendon tensibility, or how far it can extend, and the psychology of horses)." Haussler said.
Healthy Horses Workshop
For the past seven years the AAEP has offered a meeting for horse owners called the Healthy Horses Workshop at its annual convention in December. The event made its first summer appearance during AAEP Focus, and it covered topics stretching far beyond lameness. Here is a sampling of what was covered.
Ed Boldt, DVM, owner of Performance Horse Complementary Medicine Services in Fort Collins, Colo., said acupuncture and chiropractic could be very beneficial in treating problems such as acute laminitis, arthritis, and even decreased libido in stallions. Boldt emphasized that the purpose of these methods is not to replace what veterinarians are already using, but to add other weapons to their arsenal. "Most of us, as veterinarians utilizing these practices, don't like the term 'alternative medicines,' " Boldt explained. "It's a complementary form of medicine. It's another modality for us to use. We're not trying to turn our back on surgeries, lameness exams, or nerve blocks."
Infection Protection: It's Not Just About Vaccinations Anymore
Josie Traub-Dargatz, DVM, Dipl. ACVIM, of Colorado State University's College of Veterinary Medicine and Biomedical Sciences, shared her thoughts on control of infectious disease. She stressed that horse people are very positive and more likely to think they've got the next winner than consider negative things that can happen. But because disease is prevalent in the equine world, a proactive approach is necessary.
The principles of disease control are not new, but recent infectious disease outbreaks remind us of the necessity of implementing controls. Traub-Dargatz noted that treatment for illness has multiple impacts: It is expensive; poses some level of distress to the horse; sets up a risk for adverse drug reactions; and when antibiotics are used, there's always the possibility that the bacteria might become antibiotic-resistant. In addition, movement of horses is often impacted, and in the case of persistent infection, the value of the horse mght be affected.
Traub-Dargatz suggested that the best plans are to optimize a horse's resistance while also minimizing the horse's risk of exposure to disease organisms. Horses living in varying lifestyles experience different levels of exposure risk; for example, a horse that is isolated on a 5,000-acre ranch is less likely to contract infectious disease than a horse living in congregated areas or showing. In today's world, Traub-Dargatz noted that horses live more like people, traveling long distances by van or plane.
There are predisposing factors to disease. Horses at higher risk include foals and aged individuals, or any horse suffering from some alteration in intestinal function or being treated with medications. Any horse that experiences stress is more prone to contracting disease. Stresses include showing, training, competition, hauling, poor stabling ventilation, social dynamics, and nutritional deficiencies--pretty much whatever we do or don't do with our horses can impose a certain level of stress. To add to this, Traub-Dargatz mentioned increased opportunities for exposure through commingling, insect vectors, or contaminated feed, water, or the environment. She puzzled over why people would feed next to the gate where every person and every horse would tread through the hay, contaminating it with dirt and manure.
She emphasized that the previous expectation has been that vaccination will always protect against disease, but this is problematic since not all diseases have a related vaccine and not all vaccines are 100% effective against disease. Core vaccines recommended for all horses irrespective of their breed or use include tetanus, Eastern and Western equine encephalitis, West Nile virus, and in some areas of the country, rabies. For other immunizations, Traub-Dargatz recommended discussing with your vet the best program to tailor to your horse's use and threats in your region.
The Workshop to Come
The next installation of the Healthy Horses Workshop will be held Saturday, Dec. 1 in Kissimmee, Fla.
The event will feature seminars and demonstrations addressing horse health topics that are important to horse owners, as well as a special demonstration by Olympian David O'Connor.
The topics and speakers for the event are:
Equine Dental Care What Every Horse Owner Should Know--Rob Arnott, BSc, DVM;
Acupuncture & Chiropractic The Science Behind It and How It Helps Your Horse (demonstration)--Heather Heiderich, DVM;
How Horses Learn The Science of Natural Horsemanship--Jennifer MacLeay, DVM, Dipl. ACVIM, PhD;
One-Step Horsemanship The Sensible Approach To Horse Handling (demonstration)--David Hayes, DVM;
A Revealing Look Into the Makings of a Champion (demonstration)--David O'Connor.
For a complete schedule, visit the Horse Owner section of www.aaep.org.
This year's afternoon horse demonstration, titled "David O'Connor: A Revealing Look Into the Makings of a Champion" featuring Olympian David O'Connor, will give attendees a look into his past experiences and accomplishments while he demonstrates the horsemanship skills needed to handle both the green horse and experienced horse.
The Healthy Horses Workshop, held in conjunction with the AAEP's 53rd Annual Convention, will take place from 8:00 a.m. to 6:00 p.m. at the Osceola Heritage Park, Kissimmee Valley Livestock Show Pavilion. The pre-registration fee through Nov. 7 is $75; on-site registration will be $90, with lunch included in the cost of registration. To register, again visit the Horse Owner section of the AAEP Web site, www.aaep.org. You also can also register for this event by calling the AAEP office at 800/443-0177.
By Nancy S. Loving, DVM, and Chad Mendell
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