Although the majority of people can tell when a horse is very lame by his unequal gait, yet it requires much experience to detect the leg upon which the horse is lame, and especially if the lameness is slight; and still more experience, with a certain amount of anatomical and physiological knowledge, is needed to discover, in many cases, where the seat of lameness is.
Percivall defines lameness "as the manifestation in the act of progression, by one or more of the limbs, of pain or weakness, inability or impediment." Under this heading we may, for convenience sake, include "pointing" of the foot, any unnatural position assumed by the horse, and altered action which indicates unsoundness. Irregularity of gait is commonly supposed to constitute lameness, but we may have a lame horse going level when he is equally affected in both fore or in both hind legs. Although deficiency of action is its usual cause, we find that in stringhalt lameness is due to its excess.
In the examination of a horse for lameness, we should first endeavour to fix upon the affected leg, and then we should try to discover the seat of the disease in that limb. When it pains a horse, whether moving or standing still, to put the natural share of weight on any particular leg, or to bend it, or when he is unable to bend it with freedom, he is then lame. Hence to detect lameness we should endeavour to observe any tendency to favour one limb, or disinclination or inability to bend it; or any want of freedom in the gait.
Our first step should be, if possible, to see the p 2 animal in the stable, when he is standing quietly, and free from all excitement. He will then, if sound, often rest one hind-leg by bending its fetlock, while he keeps both fore-legs firmly planted. He will, after a time, ease the other hind-leg, which, in its turn, will be relieved by its fellow, and so on. Although he may stand with one fore-leg slightly advanced before the other, still it will never, unless when diseased, be relieved of its own share of weight, for he will always stand, when on level ground, with equal bearing on both fore-legs. A fatigued horse may rest a near hind and an off fore, or an off hind and a near fore, alternately, without disease. A horse lame in one fore-leg usually stands with his pastern straighter than that of the sound one.
If we find that the animal points with one foot, while maintaining a position which indicates that he prefers to stand in a constrained attitude rather than put weight on it, we may reasonably suspect that limb.
As a general rule, when the disease is in the front of the foot, the animal rests his heel on the ground; when towards the heel, he points with the toes and raises the heel. The former is the case with laminitis, and generally in ring-bone; the latter in confirmed navicular disease.
In almost all cases of pointing, when the disease is not in the foot, the horse keeps the foot flexed, and the heel consequently raised.
In bad cases of lameness in the hind-leg, the animal often keeps the foot altogether off the ground.
At the commencement of navicular disease, the horse sometimes points with the heel down, but he soon commences to bring the toe only to the ground, and to "round" the fetlock joint. In other cases, the patient will stand perfectly firm, although in the great majority of cases the pastern of the lame limb is more upright than that of the sound one, as if he feared to put much weight on it.
Laminitis is often manifested by the horse frequently-shifting his feet when standing.
The pointing of elbow lameness is characteristic, the forearm being extended, the knee in a state of flexion, and the foot perhaps on a level with, or posterior to, its fellow. In severe shoulder lameness, the pointing - if it can be called such - is backwards, the limbs relaxed, knee bent, and the foot posterior to its fellow; sometimes the toe only touches the ground, and the whole limb is semi-pendulous, consequent upon the inability of the muscles to elevate and bring it forward without pain.
In laminitis, when the disease is in the fore-feet, the horse advances them so as to relieve the toes of pressure; when in the hind-feet, he draws back his fore-feet, and advances his hind-feet with the same object.
Animals affected with navicular disease often acquire the habit of lying down a great deal in their stalls. Oases of slight lameness behind, such as those of spavin and stringhalt, are often best seen when the horse is pushed over from one side to the other, or when turned round in his stall. We may then observe that the horse shifts the weight on one hind-leg quicker than he does on the other, which we may regard as the unsound limb.
Lameness must be very acute for the horse to show it in the walk. As a rule, the slow trot is the best pace at which to observe lameness. The animal should be led in a halter or a snaffle bridle, with plenty of rein, so that the man who leads him may not interfere with the movements of his head. As soon as possible after leaving the stable, the horse should be trotted for inspection on hard ground, which should be free from stone and inequalities. The observer may stand about twenty yards in front of the horse, and on the near side. He should note, as the animal approaches, whether he "dwells" in the slightest on one fore-foot more than on the other, and whether he nods his head. If he does either, the observer may conclude that he dwells on the sound limb, and nods his head as it comes to the ground, while the other is the lame leg, which the animal naturally favours by throwing the weight on its fellow. An exception to this is when a horse is very lame on a hind-leg - the near one, for instance; he may then nod his head on the off fore coming to the ground, so that he may throw as much weight in front as possible, which he naturally does to the sound side. When a horse is very lame in front, he may chuck up his head on the lame leg coming to the ground.
A horse lame in both fore-feet, although he may not drop in his gait, will be short in action - will go, as it has been more forcibly than elegantly expressed, " like a cat on hot bricks." Each foot is carefully put on the ground, and quickly lifted up again, while at the same time there is a rolling motion of the body.
"When a horse is suspected of being equally lame on both fore-feet, he should be taken on to soft ground and there slowly trotted. If a marked amendment in the gait is then observed, one may regard the suspicion as confirmed. The time to observe him is when turning. As the chief portion of the weight of the horse's body is borne by his fore-legs, he will not, unless when very lame, dwell on one hind-foot more than the other, but will endeavour to keep the weight off the unsound limb by "hitching" up its quarter, and consequently keeping it straighter than its fellow. Hence, when the animal has passed the observer, he should take a rear view of the croup, and should mark whether one quarter rises more than the other as their respective feet come to the ground.
When the horse has trotted past about thirty yards, he should be turned, somewhat sharply, to the right-about, for instance, while the person who is examining him should note the manner in which he turns on his off hind-leg, so as to be able to compare it with the way he goes to the left-about the next time he turns. In this second trot past, the observer should try to detect if there be any difference in the action of the horse as viewed from the off side, from that which it presented when regarded from the near. If, after two or three trots past, there be still any doubt remaining, perhaps the best way to solve it is to mount the animal and trot him, alternately slowly and rapidly, for a short distance on hard ground, and give him a few moderately sharp turns.
If we suspect the existence of spavin, we may take up the foot and bend the hock, retaining it in that position for a couple of minutes; if after that the animal trots quite sound, we may consider the joint to be all right.
In obscure cases of lameness of one leg, we may suspect bone disease - such as incipient ring-bone - as the cause, if the horse stands level in his stall, but trots very lame on hard ground.
Before putting the horse in, we should try if he backs with freedom and regularity of gait.
If no lameness be noticed, we may send him back to his stable, and, as a final test, may allow him to stand for a few hours, and then, when he has thoroughly cooled down, try him again. If he passes satisfactorily through the second ordeal, we may, as a rule, regard him to be sound in limb.
Certain obscure cases of lameness can be detected only during the first few steps the animal takes on quitting his stable, for he may subsequently "work sound." Such cases of lameness are usually caused by insidious and serious disease at its early commencement. They are quite beyond the skill possessed by the ordinary amateur.
Lameness at its first commencement, in the cross-country horse, is often evinced by want of customary freedom and boldness in fencing; while in the racehorse it is shown by a slight shortening of stride, by unaccustomed ability to "act" well on hard ground, by his showing an unusual preference for leading with one leg rather than the other, and by his changing his leg oftener than he was wont to do.