Selection and preparation of food will be materially assisted by the knowledge of the physiological processes connected with the digestion of different kinds of provender. Very interesting experiments were performed by the celebrated French physiologist Colin, and Colonel Fred. Smith remarks that some of them he can fully bear out from his own observations. To avoid any mistakes, it will be advisable to quote the statements as they occur in the description which is given of the results of these experiments by the French physiologist. No details are given as to the methods which were adopted, and the critical reader may be expected to wonder how some of the facts given could have been ascertained.
The time occupied in digestion by the stomach of the horse is in proportion to the amount of nitrogen contained in the food - if hay be given before oats the hay will occupy one part (greater curvature) and the oats another part (lesser curvature) of the stomach. If the oats be given first they are deposited in the greater curvature, and the hay in the lesser curvature of the stomach. The two foods in both cases remain distinct until the mass reaches the pyloric end of the stomach, from which the intestine arises. According to Colin's experiments it is best to give the hay first and then the corn, otherwise the corn is sent into the intestine before being fully acted upon in the stomach.
The arrangement of food in the stomach in layers is disturbed by the swallowing of a large quantity of water. This disturbance does not occur, however, by the taking of a small quantity of water. Assuming this statement to be true, and it certainly seems to be perfectly reasonable, it affords a strong argument in favour of the usual practice in the best stables of always having water in the trough within the animal's reach.
The above results were obtained by giving different articles of food separately, but it appeared that when the foods were mixed, as they usually are - oats, chaff, roots, etc, being given together, - the different foods remained in the mixed condition in the stomach and passed into the intestines together, that containing the most moisture passing in first. The conclusion from this series of experiments was the very obvious one, that it is not desirable to mix foods of different degrees of digestibility, as they all pass into the intestines together, whether they have been acted upon by the gastric juice or not.
Most horsemen are aware of the common impression, which is undoubtedly true, that the digestion of the horse is extremely rapid - a necessary provision, indeed, to compensate for the smallness of the stomach compared with the animal's bulk.
Colin found that very early after the commencement of a meal the stomach begins to get rid of the food; in fact, as soon as the stomach is distended to a certain point a portion of the food begins to escape into the intestine, and in a quantity proportionate to the amount which is being eaten by the horse.
It was also ascertained that the conformation of a horse exercised a considerable influence upon the function of assimilation. Horses with narrow chests, badly ribbed up, and of a light mealy colour, animals which are known as bad doers, require great attention to their diet; in short, all the food which is given to them should be of the best quality, and the rule respecting small and frequent rations must be carefully observed. That the results of the experiments undertaken by the French physiologist are highly instructive will not be questioned. The probabilities, however, are that they will not be estimated by horse-owners in general as of sufficient importance to cause any interference with the ordinary routine of the stable; nevertheless cases may occur in which a strict attention to the princqjles which have been deduced from the facts discovered will be highly advantageous.