There’s a fungus among us…

Spring has finally sprung! The sun is shining, the temperature is rising, the grass is growing and of course, what would spring be without the mud. As we usher in this season of re-birth, we also usher in perhaps the most hostile environment to maintain healthy hooves. The excess moisture can weaken the structures of the hoof, making them more susceptible to hoof infections.

One such infection, and perhaps the most notorious and misunderstood, is White Line Disease. White Line Disease or Onychomycosis affects the stratum medium, which is the unpigmented inner wall of the hoof, and can be fungal or bacterial in nature. It has been theorized that the fungi and bacteria work in concert creating the condition. While the spores responsible for the infection exist in all environments and climates, spring provides these opportunistic microorganisms with an environment in which they can flourish. Spring provides warmth, moisture and an anaerobic environment, all of which benefit the progression of a hoof infection. The inner wall acts as the host when infiltrated by the spores via a crack, puncture or weakened white line (nail holes are notorious for carrying the spores into the wall). Once the spores embedded in the hoof mature into fungi, they feed on the stratum medium.

As the infection takes root and begins to breakdown the inner wall, it becomes softer and chalky. As it progresses, areas of separation between the outer wall and white line become evident. Only in extreme cases is the white line actually involved. At this stage the areas of separation will also be accompanied by blackened, necrotic tissue with a cheesy appearance. It is important to note that while the problem is only visible on the solar surface of the wall, it may extend as far up as the coronary band. If the infection is left untreated it will cause lameness and in extreme cases laminitis.

White Line Disease, like most conditions affecting the foot, is easier and less invasive to treat the earlier it is diagnosed. The obvious course of action is to kill the fungus present, but keep in mind that the spores present in the foot are laying it wait to mature into fungus given the proper environment. It is not uncommon to fail eliminating the problem long term with products such as Thrush Buster, Save A Hoof and other broad spectrum bacterial-fungicidial products that only eliminate the fungus and not the spores.  Even the old stand by bleach fails to eliminate the spores and is very harsh to the foot. Many times the condition appears to be cleared up, but then reoccurs with vengeance. The reason being, these products not only kill the fungus, but healthy tissue as well due to their harsh chemical make-up. This new bed of necrotic tissue provides the still present spores with a suitable environment to mature into fungus and the cycle continues. Therefore, it is highly suggested that the foot be treated with a non-necrotizing anti-fungal solution. I recommend the use of a hypochlorous compound which effectively eliminates the fungus and spores. The two products available containing a non-necrotizing hypochlorous compound are Cleantrax, a powder, and White Lightening, available in liquid or gel. I prefer the White lightening liquid; because it is can be used topically, as well as, a soak whereas Cleantrax is only meant as a soak. The early stages of the infection can be treated topically, with advanced stages requiring more aggressive treatment in the form of soaking and wrapping the foot for a period of time. If you need assistance locating either product feel free to contact me and I will point you in the right direction.

Beyond, the use of an anti-fungal, some cases require a portion of the wall be resected or removed. This involves removing the unattached wall which exposes the infection to the air and allows easier treatment. Typically the structures involved are avascular and the process can be performed without invading vascular tissue. If preformed properly a horse will remain sound after the resection in most cases, although there may be some initial sensitivity. While there is some debate on whether or not a resection should be performed in light of the penetrating anti-fungal products now available, experience has taught me that the pockets created by the infection invite foreign objects, such as small rocks, to wedge themselves in the gaps. Subsequently, every time the horse steps the rock or stone presses on the sensitive structures of the foot causing lameness. I have had horses with white line separation that appear dead lame, return to soundness after resecting the portion of the wall at the separation and finding a stone of rock lodged in the pocket created by the infection. Due to the fact that the fungi and bacteria involved thrive in an anaerobic environment, filling the gaps would be counter productive.

As we’ve have all heard, “Prevention is the best medicine” and it rings true when discussing hoof wall infections. It is impossible to eradicate the spores responsible for these infections from our horse’s environment; therefore we must look in terms of how to manage our horse’s feet to be resistant to infection. First and foremost, maintain a regular trimming schedule. A healthy, well trimmed foot generally does quite well at resisting infection. Secondly, especially if your horse has problematic feet or has had problems with white line disease in the past, is to routinely purge your horse’s feet of the spores. This involves soaking your horse’s feet in an antifungal solution then wrapping them in a plastic bag for a half an hour. This allows the gases released by the solution to continue to purge the foot.

While this is not the only method of treating or preventing white line disease, it is the method that has yielded a great deal of success for me. If you suspect your horse has white line disease, step one is to notify your farrier or trimmer. Waiting to ask him or her about it the next trim will only allow the problem to spread. Until next month, God bless you and your equine partners.