By Suzie Middlebrook BSc | Cavalor Nutrition Specialist

One of the most common ailments affecting horses today is arthritis. While most people are familiar with this disease, few understand the causes of arthritis and the process that can lead decreased performance or mobility in the horse. A more thorough understanding of this complex disease can help the horse owner better prevent and manage arthritis in their own horse. Breaking down the word arthritis to its Latin roots helps us get to the basics of the disease: arthro- means “pertaining to the joints” while “-itis” means inflammation. There are three major types of arthritis: osteoarthritis, rheumatoid arthritis, and traumatic arthritis.

Osteoarthritis is the most common type of arthritis in the horse and is caused by the degeneration and/or calcification of the cartilage. In a normal joint, this cartilage caps the ends of the bones that would otherwise come in contact with other bones. As the cartilage deteriorates, bone-on-bone contact at major joints can occur. This type of arthritis is slow, progressive, and irreversible and can be exasperated by excessive work, movement restriction, or poor shoeing.

The second type of arthritis is rheumatoid arthritis, an autoimmune disease affecting the joint capsule. This condition is often characterized by swelling and pain at the joint, particularly of the synovial membrane. The synovial membrane is the soft tissue structure that surrounds the joint capsule and contains lubricating synovial fluid. While true, immune-mediated rheumatoid arthritis is not often diagnosed in horses, a very similar inflammatory process including joint swelling and synovial membrane irritation has been commonly observed.

Galway International HT, Galway

Robyn Fisher

The final type of arthritis regularly observed in horses is traumatic arthritis. This type of arthritis is caused by an acute injury or long-term excessive or abnormal use. Any injury, movement, or irregular conformation that affects the usage of the joint can result in negative changes in that joint.

There are two main causes of arthritis: general wear and tear and inflammation. General wear and tear is most often associated with osteoarthritis and similar to when the shocks wear out on your car. A loss of strength in the muscles, tendons, and ligaments can lead to joint instability, thereby increasing the amount of stress on that joint. As the horse ages, bone density and strength also decrease, which can further accelerate joint degeneration. Consistent work suitable for the horse’s fitness level can help slow the progression of osteoarthritis since strong tendons and muscles help support the joint and prevent excessive wear from occurring.

In contrast to general wear and tear, which can only be slowed rather than treated, inflammation of the joint capsule and its surrounding structures can be possibly treated and prevented. The majority of injectable and oral arthritis treatments target inflammation-caused arthritis. The joint can become inflamed whenever the joint is overtaxed, such as landing off of a jump a bit funny, or with just repeated overuse. Inflammation can lead to acute or chronic swelling, pain, and stiffness in the affected joint. If this inflammation goes untreated, the horse can experience a reduction in mobility. This joint inflammation can sometimes be a result of an immune reaction by the body, causing the proliferation of various inflammatory agents within the joint capsule.

Another possible cause of joint inflammation would be due to an abundance of oxidative metabolites or free radicals within the joint. When the muscles near a joint are overworked, they produce a number of metabolites. These metabolites can often have a destructive effect on the surrounding tissues, in particular the joint. Free radicals, often found amongst the metabolites, are extremely reactive and will bind and destroy almost anything, including important components within the joint capsule, including hyaluronic acid, collagen, and the cartilage itself.  The more work the horse does, the greater the number of free radicals produced.

The primary way to prevent arthritis is to interrupt the inflammatory process. This can be done in three ways: topical, oral, or injectable. Topical intervention would be any cooling or pain-relieving treatment applied to the skin of the horse, such as ice, cooling gels, or anti-inflammatory ointments. This option is best used immediately after work to help stop the inflammation before it is able to take hold.

Matt Mills

The second option would be through oral administration. Oral anti-inflammatory interventions, including joint support supplements and pharmaceuticals, are best used preemptively and often have a cumulative effect. For horse owners more interested in a natural anti-inflammatory option, it is best to feed items that are known to have anti-inflammatory properties, such as omega 3 fatty acids or a variety of different herbs commonly used in holistic medicine to treat rheumatoid arthritis. The addition of antioxidants such as vitamin E and beta carotene can also help prevent the deleterious effect free radicals can have on the joint capsule. These nutrients bind and absorb the free radicals, thereby neutralizing them.

While many horse owners may choose to use nonsteriodal anti-inflammatory drugs (NSAIDs) such as phenylbutazone or flunixin meglumine, it is important to recognize that these medications can often cause gastrointestinal issues including gastric ulcers. Instead, NSAIDs should be reserved for acute injuries that require rapid anti-inflammatory relief.

The injectable medications, containing high concentrations of anti-inflammatory ingredients, is the final way horse owners can also interrupt the inflammatory process. These treatments are often injected into the system through the muscle or the vein or directly to the affected area via joint injections. While these treatments are generally believed to be the most effective, they are often the highest risk because of the opportunity for pathogens to be introduced directly into the body. This risk is particularly true for intraarticular or joint injections since a joint infection can easily spell the end of the horse’s sport career.

In addition to the thoughtful incorporation of various anti-inflammatory inventions, proper management is essential to the long, successful, and sound career of any horse. Every horse benefits greatly from regular movement through a consistent work program and turn-out. A proper exercise program also helps ensure that the horse isn’t overworked and is fit enough for the demands of their workload or sport. By combining good horsemanship with an effective anti-inflammatory regime, a horseman can help prolong the active and arthritic-pain-free life of their equine companion.

 

About Suzie Middlebrook, BSc | Cavalor Nutrition Specialist

Suzie Middlebrook is a budding equine nutritionist and lifelong equestrian. She graduated from California Polytechnic State University in San Luis Obispo, CA with her bachelor’s degree in animal science where she focused on equine and wildlife nutrition. While there, Suzie was instrumental in a number of feeding trials and experiments that looked at the fiber and mineral digestion in a number of different herbivorous species, including the red panda, the leopard tortoise, and the horse. Her personal project looked into developing an accurate and practical digestion model for the endangered red panda which she presented as an undergraduate at the Association of Zoos and Aquariums/Nutrition Advisory Group conference on Zoo and Wildlife Nutrition in 2011. Suzie loves talking and teaching about the peculiar nuances of equine nutrition and is able to do so as the Nutritional Specialist for Cavalor North America. When not “nerding out” on nutrition, Suzie enjoys competing her two horses in dressage and eventing, trail running, and playing with her boxer dog.