(a) THE FOOT WITH UNEQUAL SIDES.
Definition.—The foot thus affected has one side of the wall higher than the other.
Symptoms.—This deformity is the better recognised when the foot on the floor is viewed from behind. In addition to the difference between the height of the inner and outer heel is seen at once a deviation in the normal direction of the horn. That of the higher side is distinctly more upright than that of the lower, and runs from above downwards and inwards towards the axis of the foot, while the horn of the lower side maintains its normal direction of downwards and outwards.
From what we have said before on contracted foot, this bending in of the wall of the upright side will at once be recognised as a form of contraction. It is, in fact, contraction confined to one-half of the foot only, and, as a result, the upright side of the crooked foot is prone to the troubles arising from that condition. Corns are frequent, and atrophy of that half of the frog on the affected side supervenes. With the inflammatory changes accompanying these conditions we find the horn of the affected side deteriorating in quality. It becomes dry and brittle, and extremely liable to sand-crack. At the same time, thrush of the contracted frog begins to make its appearance.
Causes.—More often than not this condition is a result of the conformation of the limb. According as the build above inclines the animal to 'turned in' or 'turned out' toes, so shall we have feet with a wall crooked inwards or crooked outwards; and it may be mentioned here that the evil results inflicted on the foot by ill-shaped limbs above will make themselves the more readily noticed when the animal comes to be shod for any length of time. So long as a natural wear of the foot is allowed, so long does it accommodate itself to the form of limb above. So soon, however, as the shoe is applied, and a more or less equal (and in this case harmful) wear by that means insisted on, so soon does this abnormal change in the height and direction of the horn fibres begin to make itself seen.
While arising in the majority of instances from faulty conformation of the limb, crooked feet may also be brought about by bad shoeing, or by unequal paring of the foot, and, in a few cases, from unequal wear of the foot in a state of nature.
Treatment.—Although it may be taken as a rule that lowering of the higher wall, even if persisted in at every shoeing, will do nothing towards remedying the primary cause (viz., the evil conformation of the limb), yet it will serve to keep the condition within reasonable limits. In this case, while removing so much of the wall as is deemed necessary, care must be taken to leave uncut the sole and the bar. Leaving these intact gives us two natural and very potent protections against the contraction already mentioned as impending.
Where, by reason of the thinness of the horn or other causes, sufficient paring to equalize the tread cannot be practised, then the same end may be arrived at by the use of special shoes. That branch of the shoe applied to the half of the foot with the lower wall should be thickened from above downwards. Or, on the same branch, may be turned up a calkin of sufficient height for the purpose. Of the two methods the first is preferable.
In any case, whether depending upon paring, or upon the use of a special shoe, the animal should be sent to the forge quite often, for it is only by a well-directed, and therefore constant, application of the principles here laid down that improvement may be brought about.
When marked contraction of one-half of the foot is present, it will be best treated with the expanding shoe of Hartmann, already described in the section of this chapter dealing with contracted heels (see Fig. 76).