Your horse's trouble started with some front-end lameness. You gave them a rest, and it seemed to clear up. But it kept returning on occasion and you fear your horse may start to suffer some short strides. Today, our Douglasville vets discuss this common horse foot problem and how the nerves in your horse's hooves may be getting damaged.
What is Navicular Syndrome in Horses?
Navicular Syndrome (also known as Podotrochleosis) is characterized by degeneration of the navicular bone and its surrounding architecture in the back part of the hoof, resulting in chronic lameness affecting both forefeet. One-third of all chronic forelimb lameness in horses is thought to be caused by Navicular Syndrome.
What are the Signs of Navicular Syndrome?
Navicular syndrome is a type of lameness that begins mildly but increases over weeks or months. Both front feet are normally affected, but one appears to be worse than the other. The lameness is most obvious during the trot, resulting in a head-bob, as it is with most lameness. Affected horses' trots and canters are frequently short and choppy, and their necks and polls are inflexible.
All you may observe in subtle circumstances is that the horse does not perform to your expectations or appears reluctant to work. On hard ground, lameness or stiffness is often severe, and it may only be visible in a limited circle in one direction or the other. To reduce pain in the heel, some affected horses will "point" (hold out in front) the more painful foot.
The navicular syndrome-related lameness does not normally improve with rest, and symptoms can take several days to manifest.
Is There Treatment for Navicular Syndrome?
Treatment and management options are available once a horse has been diagnosed, but there is no single treatment that will "cure" the problem. The majority of horses with the navicular syndrome are treated with a combination of personalized medicinal treatments, farriery, and work and activity recommendations over time.
When a horse is diagnosed with a navicular condition, the first step should be a "proper trim." Shoeing then enables further mechanical manipulation, which can help mechanics even more. Radiographs are quite useful in guiding the shoeing process. The importance of proper trimming and shoeing in the treatment of this problem cannot be overstated.
The movement of the center of articulation, the alignment of the pastern axis, and the length of the breakover are all crucial aspects of hoof mechanics to consider.
A bar shoe is frequently used to "guard" the heel by reducing the amount of time it sinks into the ground. There are a variety of shoe designs, but the fundamental goal is to wedge the horse to the normal axis and keep him on soft ground. This prevents overextension of the coffin joint, which could cause the navicular to become overloaded.
Oral or injectable systemic medicines are frequently used as part of the therapy approach. Bisphosphonates are the most often utilized drug class (Osphos and Tildren). These medications function by preventing bone resorption, which makes sense considering that one of the apparent symptoms of Navicular Syndrome is the dissolution of the Navicular Bone. Phenylbutazone (bute), firocoxib, and other nonsteroidal anti-inflammatory drugs (NSAIDs) reduce pain and inflammation while also reducing lameness, but they are not always the best choice for long-term maintenance due to the possibility of adverse side effects.
Surgical techniques that alter the mechanics of the navicular (such as severing the navicular suspensory ligaments) can be beneficial in some circumstances, but they are case-specific and can be unreliable.
Neurectomy (nerving) can be beneficial for horses with advanced diseases who are unable to be made comfortable in any other manner. This entails cutting a section of each of the heel (palmar digital) nerves in the back of the pastern. It gives long-term pain relief by numbing the area, but it does not address the underlying cause of the pain. The cycle of deterioration in the hoof normally continues and may be accelerated due to increased limb loading.
Are There Any Predisposing Factors?
Yes, there are. While there are no hard and fast rules when it comes to Navicular Disease in horses, there are some trends.
For example, Navicular Disease is common in American Quarter Horses, Thoroughbred, and Warmblood breeds. It is rare in ponies and Arabians.
Further, It is most common in horses with large, heavy bodies and short feet, but this is not always the case.
What Can I Do to Help My Horse?
As your horse's caretaker, you have a vital role to play in managing Navicular Disease. Your responsibilities can include:
- Being on the lookout for this condition, especially in the predisposed breeds, and if you are considering buying a horse.
- Knowing the basic mechanics and anatomy of the horse’s foot.
- Getting your vet involved early if you suspect lameness.
- Administring the treatment and management as prescribed.
- Monotoring the horse’s response and communicating your observations to your vet.