My Mare Has Early Signs of Navicular Disease

Q. Dear Dr. Gray,

I have a 6 yo Quarter Horse mare that I compete in Western Pleasure, who has recently started exhibiting some of the early signs of Navicular disease. Sometimes she’s a little ouchy on her front feet when ridden on hard ground; taking short, shuffling strides and she’s started to stumble a little more than she used to. The farrier was out to shoe her recently and when he hoof tested her, she did exhibit some signs of soreness in her hooves.

He recommended some corrective shoeing as she is a big mare with small feet (relative to her size) and very upright pasterns and since then she has been much improved. However, I know that given her conformation the likelihood of her developing further problems down the road is high. I want to do everything I can to keep her healthy and sound because she’s a great mare. Are there any supplements that you could recommend to help keep her sound?

— BG, California

A. Dear BG,

Navicular disease is a very complicated subject that experts are still trying to figure out, starting with the challenging terminology. Navicular Disease is specifically defined as a chronic forelimb lameness associated with pain arising from the navicular bone. Navicular Syndrome, on the other hand, is a degenerative disease process involving at least one of many structures located in the back aspect of the hoof. These structures can include the navicular bone, but they can also include the navicular bursa, the joint between the coffin bone and the second pastern bone, the deep digital flexor tendon (DDF), the impar ligament, or the collateral sesmoidean ligament.

See what I mean by a complicated subject with challenging terminology? Although it sounds like you’re on the right track, I encourage you to involve your veterinarian as well as your farrier in a definitive diagnosis of what’s causing your mare to begin to travel poorly. A complete and thorough lameness examination with flexion tests, wedge tests and other manipulatory assessments, followed by local blocks, then imaging (x-rays, ultrasound, even MRI or CT) may narrow down the cause of your mare’s foot pain and help the three of you develop the best treatment and management plan for her. Since you specifically asked about the role of supplements and navicular, I’ll provide a little more detail in that area. Rather than keep horses on nonsteroidal anti-inflammatories like “bute” long-term, some veterinarians are recommending natural inflammationfighters like Boswellia, Yucca and Bromelain. Devil’s Claw is another option. And because some causes of navicular syndrome are joint-related, supplementing with glucosamine, chondroitin sulfate, HA and MSM might be a good idea. Finally, there are some ingredients which can be fed to horses to increase blood flow in the foot, such as arginine and citrulline (precursors of nitric oxide). N-acetyl cysteine and niacinamide have been shown to help protect the cells that line blood vessels, two other good ingredients to have on board. Genetics definitely plays a part in navicular disease and syndrome but there are some things you can do to help your horse involving hoof care, workload, medications and supplements.

Options Include

• Rest
• Therapeutic trimming and shoeing
• Anti-inflammatory medications and supplements
• Substances which alter blood flow in the foot (isoxsuprine, acepromazine)
• Therapeutic compounds injected directly into the joint, bursa or tendon sheath
• Compounds for arthritis given intramuscularly or intravenously (Adequan, Legend)
• New treatments tiludronate and shock wave therapy
• Palmar digital neurectomy “nerving” as a last resort surgery