The Dilemma of Pulled Shoes
Stephen E. O’Grady, DVM
There are few things as disconcerting to a horse owner or competitor than looking down and seeing your horse has lost a shoe. There are many instances when a horse will inadvertently pull a shoe such as being cast in a stall, being ridden or turned out in deep footing such as mud, severe fatigue, or during a competition such as a jumper missing a stride going into a jump or an endurance horse going down a steep hill - both of these latter examples being caused by the horse’s feet being out of position during high speed motion. There are many more examples that could be cited but suffice to say this does occasionally happen. In the picture above, note the force necessary to pull this shoe as illustrated by the bend in the shoe. This article is meant to be an overview of pulled shoes emphasizing the possible causes rather than the various farriery options available for each condition.
However, if a horse continually pulls a shoe, especially if it involves the same foot, this should be considered abnormal and a reason why it occurs should be sought. If a shoe is frequently pulled, training and competitions will be interrupted, the foot is often damaged and the farrier will often resort to using a smaller shoe or glue-on shoes. If one thinks about the mechanical aspects of movement, simply stated and for whatever reason, the forefoot is slower to leave the ground before the hind foot approaches the forefoot or the hind foot approaches the forefoot faster before the forefoot leaves the ground. Causes of pulled shoes attributed to the front foot could be dorsal migration of the heels of the hoof capsule and or shoes that are a size too small, discomfort in the palmar section of the foot, hoof capsule distortions such as a long toe-low heel or a clubfoot and especially when accompanied by a shortened anterior phase of the stride. Hind feet with low heels and the so-called ’bull nosed’ hind foot conformation have been associated with pulled front shoes. This foot conformation promotes a mild sickle hock hind limb conformation and, coupled with the decreased ground surface, may alter the stride length in the hindlimbs.
When one begins to investigate the causes of chronic pulled shoes, it is important to observe the landing pattern of the horse in motion. It is generally agreed that a horse should strike the ground with a slightly heel first or flat landing pattern. If a marked heel first landing or a marked toe first strike pattern is observed, it should be considered abnormal and the cause should be addressed. A heel first landing is best observed from the front and the side of the horse while a toe first landing is best observed from the side and from behind the horse as it walks away from the examiner. The marked heel first landing can be caused by long toe-low heel conformation, heels of the hoof capsule allowed to migrate dorsally and shoes that are a size too small. Heels migrated dorsally or small shoes decrease the ground surface of the foot and force the horse to land on an arc with the heels dorsally when compared with a horse that lands flat…this arc causes the toe flip (Figure 1).
Toe first landing is generally caused by either pain in the palmar section of the foot or a shortening of the musculotendinous unit of the DDFT commonly seen with a flexural deformity (clubfoot); this forces the horse to land on the dorsal section of the foot (Figure 2). With each of these altered strike patterns there is the potential to increase the time the foot is on the ground from contact to breakover.
Farriery to improve either type of landing pattern is straight forward…there are many papers in the section of this website that address the farrier methodology to improve these conditions. Briefly, farriery for a markedly heel first landing should strive to increase the surface area of the ground surface of the foot by trimming the palmar section of the foot such that the heels of the hoof capsule extend to the base of the frog or are on the same plane of the frog, using the appropriate size shoe, redistributing the weight bearing on the foot and, when necessary, elevating the heel. Farriery for the horse that consistently lands toe first is more complicated as it involves a clubfoot conformation, a shortened DDFT muscle tendon unit and is generally accompanied by a shortened stride. Farriery is aimed at increasing the ground surface of the foot, the appropriate size shoe, loading the heels, unloading the toe and providing heel elevation when necessary to compensate for the shortened DDFT muscle tendon unit. Again, the reader is directed to the section to find more in-depth papers describing farriery for the clubfoot.
In the author’s experience, horses with mis-matched feet chronically loose shoes and it generally involves the upright foot. Furthermore, the author will invariably find the horse shod with two different size shoes with a smaller shoe on the upright foot to discourage the shoe being pulled. It has to be remembered that when we apply a shoe size that is too small; we are decreasing the ground surface of the foot by one size.
Horses with low heel ‘bull nosed’ foot conformation in the hind feet will have an altered stride and will be more inclined to pull front shoes. In this case, either front shoe can be pulled rather than be limited to one side. If chronic pulled shoes is attributed to the hind feet, will usually rectify the problem. Horses, especially young horses, may have a hind limb conformation that increases the stride length which causes constant forging and the occasional pulled shoe will often respond to just using the next size larger shoe.
As a final note, I want to draw your attention to the picture of the shoe at the beginning of this article. Just think of the force you would have to exert at the anvil to create this bend in a cold shoe. Then try and straighten it cold! When I learned the trade, I was taught to use the least number of nails and the smallest size possible. I still only use four nails in my shoes as many of you know. My point is that with the amount of force applied to the shoe when it is pulled; it doesn’t appear to make any difference whether 4 nails or 8 nails are used. Furthermore, using fewer and smaller nails will decrease the damage to the hoof wall when the shoe is pulled!
Stay well and be safe!