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Medicines may be administered to cattle in many ways. The channel and method of administration depend on whether a general or local effect is desired, the condition of the animal, and the nature of the medicine that is to be given. The easiest method, and therefore the most common, is to give ordinary remedies by the mouth with the food, with drink, or separately. There, are, however, some conditions in which medicines administered in this way will not act promptly enough, or wherein a desired effect of the medicine on a distant part of the body is wholly lacking unless it is applied in some other way.

The various methods of administering medicines to cattle will be considered below.

By the mouth.—The simplest way to give medicines by the mouth is to mix them with the food or water. This can be done when the medicine is in the form of a powder or fluid, if but a small quantity is to be given, if it does not have a taste that is disagreeable to the animal and is not so irritant as to injure the lining membranes of the mouth and throat.

The usual method of administering bulky or unpalatable doses is to mix them with a fluid vehicle, such as water, milk, molasses, or broth, and give from a bottle. A dose given in this way is known as a "drench." In administering a drench the head of the animal should be elevated a little by an assistant. This is best accomplished when standing on the left side of the cow's head and by grasping the nose with the thumb and fingers of the right hand inserted in the nostrils; with the left hand beneath the chin the head is further raised and supported. If the animal is unruly, it may be tied in a stall or placed in a stanchion. The medicine can now be poured into the mouth by inserting the neck of the bottle between the lips on the right side. Care must be taken to avoid getting the bottle between the back teeth. The mouth of the bottle should be inserted as far as the middle of the tongue and the contents poured slowly. If the cow coughs, the head must at once be lowered to permit the fluid to escape from the larynx. If medicine is given during coughing, some of the dose may pass down the windpipe to the lungs and cause a severe or a fatal pneumonia. This is especially to be guarded against when the throat is partly paralyzed or insensitive, as in parturient paresis (milk fever). In this disease it has often happened that drenches have been poured into the lungs, thus killing the cow.

The quantity of fluid to be given in a drench depends upon the effect desired and the nature of the medicine. In impactions of the stomach very large quantities of fluid may be given—as much as a gallon or several gallons at a time. Usually, however, it is not customary or desirable to give more than from 1 to 2 quarts at a dose, and not more than a pint unless it is necessary on account of the irritant quality of the drug that has to be shielded with a large quantity of the vehicle.

Soluble medicines should be completely dissolved before they are given; insoluble ones should be finely divided by powdering or by shaking, and should be well agitated and mixed immediately before they are given. In the latter case a menstruum with considerable body, such as molasses or flaxseed tea or milk, will help to hold solids or oils in suspension until swallowed.

Balls are large pills adapted for the larger animals. Powders or gums are sometimes mixed with an adhesive substance and rolled into balls for the purpose of convenience of administration. Balls are not used so much and are not so well adapted to the medication of cattle as of horses. The process of solution is slower in the paunch of a cow than in the stomach of a horse; if the cow is so sick as to have stopped ruminating, a ball may get covered up and lost in the mass of material in the paunch and so lie for days, producing no effect whatever.

Capsules are shells or envelopes made of soluble gelatin in which powders or liquids may be inclosed. Capsules and balls are administered by being placed on the tongue well back in the mouth while the tongue is drawn forward and the mouth is held open by a block of wood between the back teeth. The ball should be dropped, the tongue released, and the block removed as nearly simultaneously as possible, so that the backward carriage of the tongue will throw the ball into the throat and lead to its being swallowed. In introducing the ball care must be taken to avoid having the hand cut or crushed. After a little experience it is possible to do away with the block of wood.

By the stomach.—Medicines are introduced directly into the first stomach by the use of an esophageal tube or through the cannula of a trocar passed into the paunch through the side. This method is used in the treatment of diseases of digestion.

By the rectum.—Medicines are usually administered by the rectum for the purpose of controlling the bowels and for the treatment of local diseases. Sometimes, however, medicines that have a general effect are given in this way when, for any reason, it is not possible or convenient to give them through the mouth. Only drugs that are readily absorbed should be given per rectum for a general effect and in somewhat larger dose or more frequently than when given by the mouth. Such stimulants as ether, alcohol, or the aromatic spirits of ammonia, diluted with from four to six times their bulk of warm water, may be used in this way.

Rectal injections, or enemata, are used in the treatment of constipation. If it is the purpose of the injection to soften hardened fecal masses, the water should be comfortably warm and may have a little clean soap in it. If it is the purpose of the injection to stimulate sluggish bowels to contraction, the water may be cold.

In giving rectal injections a rectal syringe may be used, or, better, a piece of one-half to three-quarter inch rubber hose 5 feet long with a tin funnel attached to one end. The hose is soaped or oiled and introduced slowly and gently into the rectum 2 or 3 feet. The fluid is then slowly poured into the funnel and allowed to gravitate into the rectum. The same apparatus may be used for feeding by the rectum.

By the vagina.—Medicines are inserted into the vagina, and through the vagina into the womb, in a manner similar to that of rectal administration. Most of the medication made use of in this way is for the local treatment of these organs. Following calving, during outbreaks of abortion, and in an infectious disease of the vagina, such injections become necessary.

By the udder.—Injections into the udder are now regularly made in the treatment of parturient paresis (milk fever). For this purpose a 1 per cent solution of iodid of potassium is commonly employed, although some other solutions and oxygen gas are also used. In making this injection so many precautions are necessary in relation to the sterilization of the apparatus and the teats and skin that this work should be left to a skilled veterinarian. The introduction of even a minute quantity of infectious dirt may cause the loss of the udder. For making this injection one may use one of the prepared sets of apparatus or a milking tube and funnel connected by a piece of small rubber hose. The apparatus should be boiled and kept wrapped in a clean towel until needed. The udder and teats and the hands of the operator must be well disinfected, and the solution must be freshly made with recently boiled water kept in a sterile bottle. The udder should be emptied of milk before the injection is made. After all these precautions have been observed the milking tube may be inserted and through it one-half pint of solution introduced by gravity air pressure or by syringe. There is practically no danger in this mode of treatment if it is properly carried out.

Injections into the udder are sometimes made in the treatment of garget, but so far with indifferent success.

By the nostrils.—An animal may be caused to inhale medicine in the form of gas or vapor or to snuff up a fine powder. Sometimes, for the purpose of local treatment, fluids are injected into the nose.

A medicine inhaled may have either a local or a general effect.

Medicated steam, carrying the volatile products of compound cresol solution, carbolic acid, balsam of Peru, compound tincture of benzoin, tincture of iodin, etc., may be liberated beneath the nostrils of a cow so that she must inhale these soothing vapors; but such treatment is not so common for cattle as for horses. In producing general anesthesia, or insensibility to pain, the vapor of chloroform or ether is administered by the nostrils. As a preliminary to this it is necessary to cast and confine the animal. Great care is necessary to avoid complete stoppage of the heart or breathing.

By the trachea.—Medicines are injected into the trachea, or windpipe, in the treatment of some forms of diseases of the lungs, and especially in that form of bronchitis or pneumonia that is caused by lungworms. For this injection a large hypodermic syringe, fitted with a very thick, strong needle, is used. The needle is to be inserted about the middle of the neck and between the cartilaginous rings of the trachea.

By the skin.—Although a number of drugs, notably mercury, are so readily absorbed by the skin of cattle as to render poisoning easy, medicines are not given in this way for their general or constitutional but only for their local effect.

Diseases of the skin and superficial parasites are treated or destroyed by applications in the forms of washes, ointments, dips, and powders. Liniments and lotions are applied to the skin for the relief of some near-lying part, such as a muscle, tendon, or joint. Blisters are applied to the skin for the purpose of obtaining the effect of counterirritation upon a neighboring region or organ. Cold water may be applied to the skin to reduce the temperature and to diminish congestion or inflammation in a superficial area or to reduce the temperature of the whole body. High fever and heat strokes are treated in this way.

By the tissue beneath the skin.—Hypodermic or subcutaneous injections are often made for the purpose of introducing a drug, reagent, or vaccine directly into the connecting tissue beneath the skin. Introduced in this way, the substance is quickly absorbed, none of it is lost, and its whole effect is obtained, often within a few minutes.

There are numerous precautions necessary in making a subcutaneous injection, most of which have to do with cleansing and sterilization. It is also important to select a proper site for the injection, so that blood vessels, joints, and superficial nerves, organs, or cavities may all be avoided. With due regard for the necessary precautions, there is practically no danger in such an injection, but it should be attempted only by those who are able to carry it through in a surgically clean way. Only certain drugs can be given subcutaneously, and dosage must be accurately graduated.

By the veins.—Certain medicines act most promptly and surely when introduced directly into the blood by injecting them into a vein, usually the jugular. Some vaccines and antitoxins are administered in this way. Intravenous injection should be practiced only by experienced veterinarians.