RUMINANTIA.
Digestive System.—The lips of an ox are thick and hard. The upper has no hair on it and varies in color with the color of the animal. When cattle are in good health this space is always moist.
The cheeks on the inside are covered by many small rough processes, which give them a very rough appearance.
The Tongue of the ox is stronger than that of the horse and is more movable. It is very thick and heavy at the back, pointed at the front end and the upper part of it is very rough. It is by means of the tongue that the ox takes most of the food into the mouth.
The Salivary glands are similar to those of the horse.
The Teeth differ very much from those of the horse.
The ox has no front teeth in the upper part of his mouth, their place being taken by a pad of cartilage or gristle. This pad takes the place of the upper row of front teeth. The lower row of teeth press against it when the animal is cropping grass. This accounts for the fact that cattle do not do as well on short grass as horses.
The front teeth in the lower jaw also differ from those of the horse. They are eight in number, chisel-shaped, and are loosely set in the gum.
The molars, or back teeth, are similar to those of the horse, only they are smaller and not so smooth on their upper surface. The ox has twenty-four molars or back teeth, and eight incisors or front teeth, making thirty-two in all.
The Gullet of the ox is much larger than that of the horse.
The Oesophagus or tube, which carries the food down from the mouth to the stomach is well developed, the fibers in it being very strong and possessing a double action. When the animal is eating they carry the food from the mouth to the stomach, and when chewing the cud they act the very opposite, carrying the food from the stomach back into the mouth.
The Stomach.—The student will do well to give some time to the study of this important organ of the ox, as it is very frequently the seat of disease.
The stomach has a capacity of fifty-two gallons and is divided into four separate and distinct compartments: the Rumen or Paunch, the Reticulum or Honey Comb, the Omasum or Many-plies, and the Abomasum or the true Stomach. In the first three of these the food undergoes a sort of preparatory process, while in the fourth the process of digestion is complete.
The Rumen or paunch is very large, and in an aged animal fills three-quarters of the abdominal cavity. It lies up against the left side of the wall of the abdomen, where it is attached and held to its place by the ligaments. Its situation being an important matter, as many diseases of the rumen, or paunch, are first noticed on the left side. Tapping for bloating is always done on the left side because of this fact. The walls of the paunch of an ox resemble those of the stomach of the horse, but are not so sensitive, and stand a great deal of abuse before inflammation sets in. The paunch has two openings, both of which are at the front; through one the food enters, while through the other it passes out into the next division.
The Reticulum, or honey comb, is the smallest division and resembles a honey comb in appearance. This part has little to do with preparing the food. It is provided with two openings, one in front, where the food enters, the other at the back, where it passes through into the third division. In the reticulum, or honey comb, the food is softened further by the water that the animal drinks which passes directly into the second division. The food is here pressed into balls and prepared to be forced back into the mouth to be further masticated.
The Omasum, or many-plies, is the second largest division of the stomach. When full it is ovoid in shape. It is placed just behind the second division and at the right side of the paunch. The inside is full of folds, or layers of membrane, into which all the coarse parts of the food pass and roll about until it is fine and well prepared to pass into the last division. When this part of the stomach becomes deranged and the food becomes dry and hard between the folds, the disease called impaction of the many-plies, or dry murrain, is the result.
The Abomasum, or fourth stomach, is the true digestive part. In it the food is completely digested. The walls are redder in color than those of the three first divisions and contain the glands which secrete the acids and gastric juices. This stomach has two openings, one through which the food enters and the other through which it passes into the small bowels.
The Bowels, or intestines, of the ox are divided into large and small bowels. This, together with their structure and action resembles that of the horse. The small bowels are only half the size of the horse, being about one-half inch in diameter, and about one hundred and fifty feet in length. The large bowels are not nearly so long as those of the horse and are thirty-five feet in length.
The Liver of the ox resembles that of the horse, except that it is provided with a gall bladder which resembles a pear in shape. This acts as a sac in which to store the gall during the time it is not required in digestion. When digestion is going on the wall of the gall sac contracts and forces the gall down to the food. The other glands, the pancreas and spleen, resemble those of the horse. The juices from these glands have the same action in cattle as they have in the horse.
Rumination, or Chewing the Cud.—Food when first taken into the mouth of a ruminant is but lightly masticated and mixed with the saliva from the salivary glands, after which it is swallowed, passing through the oesophagus into the rumen or paunch (first stomach). This division acts as a reservoir or storehouse for food thus eaten quickly. When the animal has time, so to speak, he lies down or stands quietly and completes the process of mastication of his food by chewing the cud. This peculiar act is performed as follows: After being softened and moistened by warmth, the food passes from the rumen or paunch into the second division—the reticulum, honey comb or second stomach. In this small globe-like compartment the food is moistened and compressed into pellets—the cud. By a peculiar reverse action of the oesophagus or gullet these pellets are taken back into the mouth for further mastication or chewing. When re-mastication is completed it is again swallowed, but this time it passes directly into the omasum, many-plies or third stomach, and thence to the fourth or true stomach.
Process of Digestion After Rumination.—Following rumination which, strictly speaking, is the first step in the digesting process, the food passes into the third stomach. The fine parts pass right along to the fourth stomach while the coarser parts are drawn between the folds of the membrane in this division and worked about until it is fine and ready to pass into the fourth stomach, where it becomes fully digested by the action of acids and gastric juices which are secreted in this part. It then passes into the small bowels, and is acted upon by the bile from the liver and the pancreatic juice from the pancreas. These juices are emptied into the first part of the small bowels through little ducts or tubes, which lead from the glands down to the bowels, just on the same principle as that of the horse. After this, throughout the rest of the bowels, the nourishment of the food is taken into the system by means of little glands which are situated in the coating of the bowels. The nourishment when once in the blood goes to supply the different parts of the body, while the part containing no nourishment or undigested passes off through the back bowels in the form of feces.