There’s a fungus among us…

It’s been a year since I first used this title to introduce my column and in light of the recent weather a topic I felt worthy of revisiting. This spring has created an especially hostile environment to maintain healthy hooves. This year’s extended mud season has made our horse’s hooves much 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 warmth and moisture, the key ingredients in producing fungi. The inner wall acts as the host when infiltrated by the spores via a crack, nail hole or weakened white line. The white line can be weakened by many factors, especially flare, but the mud has certainly been a major contributor this spring. Once weakened, the white line is easily infiltrated by spores which mature into fungi that feed on the stratum medium.

As the infection takes root and begins to breakdown the inner wall, it becomes soft 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 can 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 most common course of action is to treat the problem chemically. When I originally covered this topic I myself focused on chemical treatments and I still feel it is beneficial to understand the many treatments available. When using topical treatments remember most kill the fungus present, but have no effect on the spores present in the foot which are laying it wait to mature into fungus. 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-fungicidal 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, such as clean trax or white lightening, which effectively eliminate both the fungus and spores.

My original article also stated 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 sensitive tissue. If preformed properly a horse will remain sound after the resection in most cases, although there may be some initial sensitivity. While I still believe resecting the wall is called for in some cases, especially when a rock is wedged in the separation, I have limited it to the hoofwall quarters. Removing excess toe or heel, many times leaves the horse overly sensitive.

Since originally covering the topic, I have implemented specialized trimming techniques which focus on strengthening the white line, which is proving to be the greatest tool in preventing and treating white line infections. Generally I trim a horse with a white line infection; much like a horse with flare (most cases involve both). Relieving the wall to the edge of the sole and applying a substantial roll to the wall can do more than most chemicals. Like much of natural hoofcare, this is a departure from the traditionally held belief that the wall is solely responsible for supporting the horse. Common sense dictates that if the white line’s integrity is compromised, it must be rehabilitated and strengthened. Relieving the leverage off the white line and engaging it at ground contact will tighten the junction and create an infection resistant hoof.

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. I have written this time and time again, but maintaining a regular trimming schedule is your greatest tool. The worse the weather the more important this fact is. Until next month, God bless you and your equine partners.