At this time careful search may or may not discover visible contraction of the diseased foot. This condition, however, soon follows on by resting the foot in the stable or relieving it when at work. In the former case it is partially flexed and advanced more or less so as to take it away from the bearing, and in the latter the heel is kept as far as possible from the ground, and the weight is thrown on to the front part of the foot. All the changes which follow upon this are in the direction of contraction of the heels, and as this takes place the foot narrows behind. With the progress of the disease and the constant use of the sound foot it also begins to show signs of trouble, and the lameness which had hitherto been confined to the one now appears in the other. Knee action becomes defective, the step is short and “proppy,” or, as it is commonly expressed, “groggy.” On leaving the stable the horse is very lame, but as he continues to move the lameness in great measure passes away. The fore limbs are now upright, or he stands over at the knees, a fulness appears in the hollow of the heel, the foot becomes blocky, and the crust thick and dense, the sole is unusually concave, the frog wasted, and may be affected with thrush.
Treatment.—It may be accepted as true that once the disease is started its progress continues, and sooner or later brings its victim to the knacker’s.
In some horses the malady makes slow progress, but in others it is rapid and destructive. If the disease cannot be cured by the adoption of palliative treatment, much useful work may be obtained from an animal affected by it. When navicular disease is known to exist, special attention will, of course, be given to the shoeing. Here much may be done to keep the disease in check.
We see by the concavity of the sole and the contraction of the heels that the latter have not been allowed to come to the ground in the ordinary way. This is the keynote to which attention must be directed in regard to treatment. The heels must be defended by slightly thickening the shoe at this point, and the introduction of a leather or india-rubber band to break the jar on concussion.
The crust must not be allowed to grow unduly, but must be kept down by occasional rasping. By doing this, contraction of the foot is to some extent prevented, and the conditions of its elasticity preserved.
When in the stable a cold wet swab should be worn; it softens the hoof, prevents contraction, and enables the animal to work with comparative ease. Horses with navicular disease, especially those advanced in years, should be kept at work. Of all occupations none suit these animals like working on the land, where the feet meet with the least resistance. Mild counter-irritants to the coronets while still working may be applied, but on no account should the animal be allowed a “long rest,” during which he loses condition, and with it all the courage by which he has been enabled to “suffer and to work.”
The last and final act in the treatment of navicular disease is division of the plantar nerves.
THE BEECH.