Looking for Symptoms

By David Thill
July, 2017

Early action could help decrease the long-term effects of osteoarthritis

Osteoarthritis – often referred to simply as OA – is painful, not only for humans, but for their horses, too. The condition, in which the horse’s protective joint cartilage erodes, leading to bone exposure, is one common factor contributing to lameness. But lameness is not the only symptom. By looking for other earlier symptoms, such as inflammation, and taking steps to mitigate them, horse owners may be able to keep OA from becoming a significant problem.

Symptoms

Lameness is often considered the primary sign of OA, but other signals may come earlier, says Stacey Buzzell, DVM, equine technical services manager at Nutramax Laboratories Veterinary Sciences, Inc. “This can be as simple as a change in demeanor under saddle or in the field,” she says. Other early indicators include an unwillingness to move forward or to work, a change in activity level during turnout, and difficulty working with the farrier.

Horse owners must not jump to conclusions, though, says Buzzell. “It is very important for owners and trainers to be familiar with each horse as an individual in order to pick up on subtle changes, and rule out medical causes with the veterinarian, before attributing any changes to a behavioral issue,” she says.

The only specific cause of OA is development of inflammation within a joint, says Buzzell. Inflammation, she says, can happen as a result of repetitive concussion of the joint, poor conformation, injury, infection, and instability.

Inflammation activates enzymes that lead to cartilage degradation. This process leads to exposed bone, which can progress to sclerosis – increased bone formation and hardening – which can then lead to osteophytes, or bone spurs, and joint fusion, Buzzell explains.

Hoyt Cheramie, DVM, M.S., DACVS, senior manager, equine specialist in large animal veterinary services at Merial, Inc., says trauma – which can lead to inflammation – is the most common cause of OA. Trauma, he says, can lead to one of several conditions. These include:

Synovitis – inflammation of the inner synovial (or joint) lining.
• Capsulitis – inflammation of the fibrous, outer joint capsule.
Sprain – injury of ligaments of the joint.
• Intra-articular fracture – fracture of the bone that extends to the joint surface.
• Meniscal tear – injury to the meniscus of the stifle (the femorotibial joint).

Cheramie adds that “most spontaneous joint disease in the horse is likely associated with microtrauma to the synovial lining and joint capsule due to daily work and use. Without early, appropriate therapy, the inflammatory process often progresses to eventually result in osteoarthritis.”

Symptoms such as pain, stiffness, and decreased range of motion can appear from very mild to severe, “and may not necessarily reflect the severity of the underlying damage in the joint,” cautions Cheramie.

Buzzell says that conformation can be a strong indicator of the likelihood that a horse will develop OA. Poor conformation can place undue stress on a horse’s joints, she says.

The horse’s activity level can also play a part. For example, athletic horses might perform activities, such as cutting, jumping, and sliding stops when reining, that place extra stress on their joints.

Age may play a role as well, says Buzzell. Just as cartilage wears naturally with age in humans, the same is true for horses. However, she adds that age is not a definitive factor when it comes to determining the likelihood that a horse will develop OA.

Again, says Buzzell, it depends on the individual horse, whose specific history “would be more likely to paint a clear- er picture of susceptibility.” Previous injuries or infections can have some bearing, she says.

Treatment

Managing a horse’s joint health and being aware of changes in the animal’s behavior are the best means for prevention, says Buzzell. Appropriate joint management, she says, includes maintaining a healthy weight, visiting the farrier regularly, ensuring the horse partakes in regular activity with adequate warm-up and cool-down periods, “and identifying and addressing any signs of pain or lameness early on with the guidance of a veterinarian.”

Horses will naturally have inflammation caused by daily work and activity, and that inflammation can be exacerbated by factors such as poor conformation, injury, and over-work, says Buzzell. “This inflammation has to be managed and kept under control to prevent or slow the progression of OA.

“This doesn’t mean that [horses] all require a non-steroidal anti-inflammatory (NSAID) every day or shouldn’t be in work.” Buzzell points out that regular movement helps to promote the transfer of nutrients in and wastes out of the cartilage cells – “somewhat like a sponge.”

OA isn’t totally preventable, Cheramie admits. But horse owners can still try to reduce its effects, he says. He also believes inflammation management is important – specifically, early identification of joint inflammation. Addressing initial signs, such as mild heat, swelling, stiffness, and qualities that are “just not right” in the horse’s movement allows for earlier therapy to stop or minimize the inflammatory process and progression, he says.

Buzzell says that regular veterinarian visits will help en- sure early OA detection, and regular trimming or shoeing by a proficient farrier can help reduce joint stress. Also, she says, exercise combined with a balanced diet aids in maintaining a healthy body weight, which helps to prevent undue stress on the joints.

Sometimes non-invasive symptom treatments are the most effective management strategy for OA, says Buzzell – “but that decision should be made with the veterinarian based on the individual animal and rate of progression of the disease. Many cases will involve a combination of things, or multi-modal management, which will change over time.


Joint Health Products from Dechra Veterinary Products

Orthokine® irap 60: When osteoarthritis occurs, excessive amounts of the aggressive signaling protein interleukin-1 form inside the joint, causing inflammation and leading to further damage in the joint. The principle of Orthokine irap 60, or interleukin 1-receptor antagonist protein, is to use the body’s own natural defense against these signaling proteins. It is collected via specialized syringe and administered via intra-articular injection.

Phycox® Joint Supplement Max EQ is a formula aimed at maintaining healthy joints and flexibility. It contains phycocyanin, a natural antioxidant that supports the body’s normal defense against the harmful effects of free radicals that cause cellular damage and inflammation. It also contains boron for bone health, creatine monohydrate for muscle health and strength, as well as cranberry extract for urinary tract health. It carries the National Animal Supplement Council quality seal of approval, and is sold through veterinarians.

(Source: Shelly Derks, marketing manager, equine and specialty products, Dechra Veterinary Products)

Joint Health Products from Merial

Equioxx® is a Non-steroidal anti-inflammatory drug (NSAID) containing firocoxib as the active ingredient. It is available in paste, tablet and injectable formulations and is a prescription med- ication. As an NSAID, Equioxx works by blocking the production of prostaglandins through cyclooxygenase (COX) enzyme inhibition. It is considered a “coxib” or highly selective COX-2 NSAID, thus blocking the production of prostaglandins responsible for pain and inflammation while sparing production of COX-1 prostaglandins that support blood flow, clotting and gas- troprotection.* Equioxx is designed for once a day dosing.

(*Clinical relevance has not been determined.)

Legend® (hyaluronate sodium) is a hyaluronic acid joint therapy available for both intravenous (IV) and intra-articular (IA) administration. Legend Inject- able Solution treats joint dysfunction of the carpus or fetlock in horses due to non-infectious synovitis associated with equine osteoarthritis. Treatment with Legend may be repeated at weekly intervals for up to three treatments. Leg- end delivers the same efficacy whether administered IV or IA. IV administration is ideal for treating clinical and subclinical synovitis when an IA injection may not be warranted.

(Source: Hoyt Cheramie, DVM, M.S., DACVS, senior manager, equine specialist in large animal veterinary services at Merial, Inc.)

Joint Health Products from Nutramax Laboratories

Cosequin® is an oral joint health supplement for horses. The base of all four of the supplement’s formulas is FCHG49® glucosamine hydrochloride and TRH122® chondroitin sulfate. These ingredients work to support the structure and maintain the health of the cartilage and have been shown in studies to work better together than either ingredient alone. The Cosequin® original formula can benefit young horses entering into work or horses with healthy joints in light work.

Cosequin ASU further expands on the Optimized formula with the addition of NMX1000® avocado/soybean unsaponifiables (ASU), an extract from the oil of the avocado and soybean. The synergistic effects of glucosamine, chondroitin, and ASU have been shown in cell culture studies to reduce media- tors of the inflammatory response that can lead to cartilage breakdown. Cosequin ASU Plus takes the line a step further with hyaluronic acid (HA) and green tea extract (EGCG). The combinations of HA/ASU and EGCG/ASU have been shown to improve upon the supportive and protective effects of the

ingredients alone. These two formulas can be used in any horse, but are ideal for horses in heavy work or those that have cause for concern relating to their joint health.

Cosequin Optimized with MSM builds on the original formula with a higher level of glucosamine and the addition of methylsulfonylmethane (MSM). There is a limited amount of research on MSM, but studies have shown its ability to function as an antioxidant and support the health of the cartilage. It is an organic source of sulfur that supports the structure and flexibility of the cartilage. Horses in work with healthy joints would be ideal candidates for this formula.

Welactin® Equine is an omega-3 fatty acid fish oil supplement providing DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) in a peppermint-flavored liquid. Fish oil has also been shown to support joint health through the modulation of mediators involved in the inflammatory response by EPA and DHA, supporting comfort and improving stride length in horses.

(Source: Stacey Buzzell, DVM, equine technical services manager at Nutramax Laboratories Veterinary Sciences, Inc.)

Joint Health Products from Bimeda Animal Health

Flunazine® (flunixin meglumine) injection and oral paste relieves pain associated with osteoarthritis by reducing inflammation in the joint.

Tandem Oral is a supplement containing joint-healthy ingredients such as chondroitin sulfate, glucosamine, hyaluronic acid and MSM (methylsulfonylmethane). Those ingredients are known to help support the production of cartilage and maintain normal inflammation levels in the joint.

Butatron® (phenylbutazone) is indicated for managing pain and inflammation due to osteoarthritis. Butatron is available in tablet form.

Polyglycan is a joint lavage. It helps restore synovial fluid (the liquid “cushion” between bone ends), thereby restoring the physical characteristics to aid in proper joint function.

(Source: Emmanuelle Lemaire Galliot, DVM, marketing manager, Bimeda Animal Health)

Topics: Osteoarthritis, Equine 2017 Summer

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