This form of inflammation of the mouth, occasionally seen in foals and other young creatures, is characterized by an eruption on the tongue and other parts of the membrane, and sometimes also on the lips. It resembles in its main features the malady termed "Thrush" in the human infant, and is believed to have its origin in a similar if not identical cause, viz.: a minute fungus or microscopic plant.
In certain states of the system this organism (Oidium albicans), on gaining access to the mouth, finds in the mucous membrane the necessary conditions for its growth and development, as the result of which inflammation is produced, at first in numerous small scattered centres, and later over a considerable surface of the cavity. In some cases it may reach the throat and extend to the air-passage, or pass downward along the gullet and invade the stomach.
As we have previously remarked, aphthae is a disease of early life, and seldom seen after the suckling period. Although characterized by an eruption in the mouth it is often attended by more or less constitutional disturbance, in connection with which derangement of the stomach is a marked feature. In some instances, however, it is of a mild character and passes away without attracting particular notice. In the more severe form it is ushered in by general signs of illness, of which dulness, a staring coat, and looseness of the bowels are the more conspicuous. An inspection of the mouth discloses a number of grayish-white spots scattered over the tongue, the cheeks, and other parts. These may be so numerous and closely packed as to run one into the other and spread over a large surface of the lining membrane. Later the month becomes covered with sores, saliva hangs about the lips, and the breath becomes offensive. Where the disease invades the throat there is difficulty in swallowing. Disordered digestion is shown by looseness of the bowels or diarrhoea, and straining may be present, when the dung is sour and foul smelling. Very young foals when observed to let go the teat without obtaining satisfaction, or when presenting a tucked-up appearance, should be examined as to their mouth. The reader familiar with sucking colts is of course aware that in health they make very frequent visits to the maternal bottle, taking short intervals of rest, varied with gallops, and returning for more nourishment in a few minutes; but a colt with a sore mouth will probably drop his ears and shake his head while trying again and again to lay hold of the teat.
In dealing with this disease it is important to remember that any unwholesome condition of the milk of the dam will not only predispose to it, but likewise tend to aggravate it when once it has become established. Attention, therefore, should be directed to the health of the mare, and care' be taken that the food and water she receives is not only of good quality but suited to her condition as a matron. Should she be at all out of health a little laxative or alterative medicine should be prescribed at once and the diet carefully selected and administered. If the dam is being worked it would be desirable to discontinue her services and restrict her movements to gentle exercise. In addition her teats and udder should be sponged with a five per cent solution of carbolic acid morning and evening.
With regard to the foal, a small dose of castor-oil at the outset of the disease, in a little warm milk, will be found of considerable advantage in cleansing the stomach and bowels from the offensive and irritating matters they contain, and aid at the same time in subduing the existing inflammation of the mouth. This may be followed by 10- to 30-grain doses of bicarbonate of potash, morning and evening, in a little of the mare's milk.
Although in slight cases the disorder in the mouth may pass off without interference on the part of the attendant, its duration will be shortened and the creature's comfort considerably enhanced by the judicious use of simple remedies - as sponging out the mouth with weak vinegar and water, or a solution of alum, or the application of borax and honey, or a mixture of glycerine and tannic acid, to the affected parts. Should the disease of the mouth be severe, and continue to divert the foal from the teat, debility and exhaustion must be guarded against by drenching the little patient with milk from the mare, or it may be encouraged to take small quantities from time to time off the palm of the hand. We have known a sponge saturated with milk to prove a useful vehicle for conveying it into the mouth when the teat has been refused. These artificial means of feeding, however, should be discontinued as soon as possible, or the youngster may acquire bad habits and prove troublesome later on. Weakness and prostration in these cases must be met by the administration of small doses of brandy added to the milk and potash prescribed above, and the little sufferer should be kept warm and protected from draught.