Hoof Cracks: 3 reasons your horse has them and how to get rid of them
Cracked hooves are a common problem that can range from single, shallow, millimeter-wide groove that takes a good look to even notice, to multiple, full thickness splits of the hoof wall that cause lameness by pinching the sensitive structures beneath. This article explains the causes of these ugly splits and how to reduce and possibly eliminate them through good hoof management strategies.
Note: this article does not deal with the less common “quarter crack“. Quarter cracks extend from the hairline down and are generally the result of chronic imbalance under extreme loads in performance horses.
The dry hoof fallacy
This “dry hoof theory” is perpetuated by the plethora of hoof oils marketed to to heal split hooves. The ragged, shelly appearance of cracked hooves gives credence misconception that the hooves lack moisture. Often, under the advice of an otherwise knowledgeable horse person, attempts to hydrate the hoof via overflowing water troughs, applying hoof creams, or old timey treatments, usually involving automotive fluids, are made.
Hoof cracks are actually the result of too much moisture. Wet (anaerobic) conditions are a contributing factor for White Line Disease, the most common cause of hoof cracks . WLD describes a common fungal invasion of the hoof wall. For more on the causes, progression and identification of WLD, check out this.
How WLD causes hoof cracks
WLD fungi seek out deep, damp, airless cavities. Hooves with flares or other damage to the hoof wall have voids in the hoof wall. These nooks will fill with muck, creating the ideal anaerobic conditions for this horn ingesting microbe to thrive.
Once the WLD has established itself deep within the hoof via the original defect, it will spread to the surrounding horn, eventually making its way to the surface as a hoof crack. The hoof splits from the inside out. This is why WLD is impossible to eradicate through topical treatments.
Hoof cracks are remedied using a three step progress: address the underlying hoof balance issue, remove the affected, contagious horn and expose the area to air to eliminate anaerobic conditions that perpetuate this hoof funk.
Underlying causes of hoof cracks
1. Flares and hoof imbalance
The coffin bone is the core of the hoof which dictates the shape and size of the capsule that forms around it. Viewed externally, the hoof wall should slope evenly away from the coronary band so that shape of the bottom hoof should echos that of the coronary band.
A flare describes an outward distortion of the hoof wall due to imbalance. If part of the hoof is left longer than the rest, that longer hoof will yield and pry away from the sole creating a flare. WLD will soon occupy the cavity between the wall and sole. Flares can be blamed on too long of interval between shoeing/trimming or can be error on the farrier’s part (although some horses have conformation that makes this more complicated). In either case, When the hoof maintained by a competent farrier and a diligent owner, flaring will be minimized. The emerging, unbent horn will be much stronger and not prone to WLD invasion.
2. Loose shoes
Loose shoes cause hoof damage, creating ideal conditions for WLD. The constant movement of the nails erodes the adjacent hoof wall. Signs of loose shoes are raised clinches well before the next appointment, hoof wall loss below the nail line, shoe loss, and a ragged appearance.
Going too long between farrier visits and wet environments cause loose shoes. Shorting the shoeing interval by a week, especially during the warmer months, when fungal problems are worst, will help. Don’t keep horses in dirty stalls or mud-lots and pick out hooves regularly.
As with flares, this can also be a result of inattention on the farrier’s part. A slightly unlevel or misshapen shoe can become loose prematurely.
Hot shoeing is a WMD for WLD. A hot fit, clipped shoe, custom fit and burned lightly to the hoof will remain snug throughout the shoeing cycle. The searing of the foot also kills any nearby microbes while sealing the hoof against moisture. For more on hot shoeing check out my post “Hot Shoeing versus Cold Shoeing“.
3. Old abscess or hoof wall injury
Cavities created by past abscessing or hoof wall injury host WLD. Many horses have a small degree of this, especially in the center of the toe. This sort of cracking is so prevalent and consistent in location, it may associated with the mid-dorsal notch of the coffin bone. An inherent weakness combined with excessive toe length would explain why horses with no history of abscessing often have these cracks.
Another source of hoof cracks caused by WLD is past injury to the coronary band. Trauma to the coronary band can cause scarring. Hoof wall grown under the blemish can be malformed. This horn is very susceptible to WLD.
Expose WLD to air
Once the underlying hoof balance is identified and addressed, the current infestation of WLD must be debrided as much as possible. This may be achieved in one session like in the top picture, or an ongoing process depending on the extent of the damage. Clearing of the muck filled crevices in the hoof is necessary to rid the hoof of the microbes.
Medicate and evaluate
After the farrier work is done, make sure that you evaluate your horse’s home. Remedy wet conditions and make sure to keep scheduled farrier visits so any new WLD can be dealt with promptly. The damaged hoof wall should be cleared daily with a wire brush to expose it to air. After cleaning the foot I would recommend applying an antifungal to the area to discourage recurrence.
Thank you for reading my post on hoof cracks. If you liked it, please feel free to share. If you have questions or comments, don’t hesitate to post here or contact me directly, or here for information on my farrier service. Don’t forget the number 4 cause of hoof cracks is not following Elizabeth’s Farrier Service via your favorite platform ;).