Interfering is a bad fault in a horse, and is mostly found in some horses predisposed thereto from a variety of causes, such as malformation in the feet, the feet being abnormally developed, resulting in pigeon-toe; the planting of the feet outward, or other unnatural positions and movements due to unshapely feet. In other horses the legs are the cause of interfering. They are either crooked, or they are not upright and straight. In others it is the chest which is at fault. The chest is thin, and this brings the legs so close together that the least unevenness of the ground will cause a little variation of the motion which brings the foot against the fetlock, the shin or the knee, and the forward-going foot strikes the other, causing pain or an open sore. Another cause is due to weakness in the legs, or to swollen fetlocks. In others it is due to a peculiar swinging motion in the feet. Any horse may interfere if not properly cared for. A horse shod with heavy shoes will interfere, so will a horse shod with too wide shoes. Some horses will interfere after they are driven twenty miles. Then the horse begins to get tired and cannot take care of his legs properly. A horse, poor in flesh, is liable to interfere. In interfering, the horse brushes the foot going forward against the other foot. Some horses strike above the fetlock, but in most cases they strike the fetlock. When the point of contact is higher than the fetlock it is called “speedy cut,” “knee knocking,” “paddling,” “cross-firing,” etc.
Colts seldom interfere before they are shod; after that they sometimes interfere, because the shoe is either too heavy or too wide – probably both – but the trouble disappears as soon as the colt is accustomed to shoes. To ascertain what part of the foot or the shoe is doing the damage, put a boot over the injured part and paint it white, then drive the horse on a trot, and that part of the hood or shoe which is doing the harm will show some of the paint. Interfering is common in both hind and fore feet.
If the fault is in the legs or feet it can be remedied by shoeing. Fig. 26 represents a shoe for interfering. This shoe is called “sideweight shoe.” In preparing the foot for this shoe, be sure to make the foot level, and it is well to cut down the hoof as much as possible in order to make the foot as small as you can. Some shoers in shoeing for interfering will pare down the outside edge low, and leave the inside high. This will throw the fetlock out and leave more room for the other foot in passing by; but it is not well for the horse’s legs to be thrown out of line that way. (see Fig. 28.) Another will shoe for interfering by putting the shoe well in under foot on the inside, leaving the hoof to stick out over the shoe about a quarter of an inch, and not rasping off this projection of the hoof. This is worse than leaving the shoe outside of the hoof, for the hoof being rubber-like, will, when striking, adhere to the leg more than to the smooth shoe. This method I would call faith cure. Some shoers will make the shoes shorter than usual, and set them well in under the heel, supposing that the injury is done by the heel-calks. This is not so, for the damage is done either with the quarters or the inside of the fore part of the foot. Fig.30 shows a shoe for this kind of interfering. The striking is not done with the hell-calks unless they project too far beyond the hoof. After the foot has been leveled rasp the hoof straight at the quarters, as shown in Fig. 31, between 1 and 2, or at the front, as indicated by the shoe in Fig. 30. In preparing the shoe remember that the rule is to have the weight on the outside, and the weight should not pass the center, as shown in Fig. 32; for if it does it will neutralize the effect you have tried to produce by placing weight on the outside. When the shoe is nailed on, be sure to hammer down the clinchings, especially on the inside, for it often happens that these are doing the mischief. If the sideweight is heavy enough it will, in a majority of cases, overcome interfering, except in case of weakness, or when the horse has been reduced in flesh. In such cases rest and ground feed are the best remedies. Nothing is better in such cases than flesh; it is the best leg spreader.
For a horse with a swinging motion in the feet, a shoe as indicated in Fig. 34 should be used. The turned out heel will prevent that swinging motion if there are sharp calks, as shown in Fig. 34. In interfering, as self-inflicted blow produces sores or horny patches on the place of contact. The blow is of different characters, ranging from a light touch scarcely noticeable to a blow that will lay open the part struck and force the horse to walk on three legs for a while or stand still. The first thing, therefore, to do is to apply a boot to protect the sore and give it a chance to heal. Next proceed to remedy the fault by shoeing, if the animal is young; if old, provide rest and ground feed which will strengthen the horse so that he can carry his feet properly. If it a bad case of interfering put on a heavy sideweight and a high calk on the inner web, but no calk in front or on the outside. This will break the gait of the horse, and then the calk can be lowered a little at a time until the foot stands level.
Speedy cut is known under different names, which have already been explained. This fault is so much related to interfering that the remedy in some cases is the same. In speedy cut the injury is higher up on the leg. In all such cases the shoer must aim to change the gait. Sideweight or tit shoes must be used to accomplish this. Fig. 35 illustrates a shoe with the sideweight outside of the edge of the hoof, the dotted line indicating how far the foot extends on the outside.
In speedy cut, the horse breaks over either on the inside or outside of the toe of the foot, and the shoe should be so adjusted that the horse is forced to break over in the center. If, therefore, the horse breaks over on the inside of the toe, a tit shoe should be used with a tit from one to two inches long. Fig. 36 illustrates a shoe of this kind. The shoe can be made with the tit either on the inside or outside of the toe as the case may require. If the horse breaks over with the toe in, put the tit on the outside, and vice versa.