B. T. SIMMS.
TREATMENT, or therapy, of disease may be defined as any effort to cure disease, arrest its course, lessen its severity, or alleviate the pain and inconvenience that disease causes. It includes the administration of drugs or medicines; physical therapy, such as massage, exercise, immobilization with bandages or splints, and application of heat or cold; and any changes in methods of feeding or handling that are made to insure recovery.
Drug and physical treatments are sometimes called direct therapy; good management may be called indirect or supporting therapy.
The art of treating disease is as old as the history of man. Written records of some of the early civilizations describe some of the diseases of domestic animals and give directions for treating them. It is an art that has never stood still. Man has constantly striven to find better methods of restoring his sick animals to good health.
The use of drugs and medicines, including biological products such as vaccines and serums, constitute the most important segment of disease treatment. Until about 70 years ago, progress in developing new and better drug treatments was rather slow because the nature of disease was not well understood and a real scientific approach to treatment therefore was impossible, and because few organized, extensive efforts to find new treatments were being made.
The improvements that were taking place were coming largely from the trial-and-error experience of practicing veterinarians. A rapid development of experimental methods of studying both the normal and the sick animal began about 70 years ago. Such studies have added enormously to our knowledge of the science of disease.
We know now that many of the treatments used in the past were aimed at the results of disease rather than at disease itself. For example, we used to see animals (and people) treated for fever. Now it is generally recognized that fever may be brought on by many different causes. The skillful veterinarian of today tries to find out what is causing the fever and then treats the disease itself. Fever medicines, which were so generally used in the early years of this century, are seldom heard of now.
Experimental studies of the action of drugs have accompanied the studies of normal and sick animals. Physiologists and pharmacologists have measured and recorded the effects of a large number of drugs and medicines on animals kept under controlled conditions. We now know rather definitely what results may be expected from the use of many of the different remedies. We know, too, that many of the remedies in common use 70 years ago have little actual effect. Furthermore, some of the treatments that were formerly in rather general use are actually harmful. For example, carbolic acid (phenol), which was used to treat wounds, did so much damage to the tissues that its use actually slowed down healing.
Experimental studies have proved that the different species of animals may respond differently to the same drug. Thus dogs are put to sleep by morphine, but morphine causes cats to become restless and excited. Chloroform is a fairly safe anesthetic for the horse but a dangerous one for the hog. Dogs may be anesthetized with ether rather easily, but cows cannot be.
All these developments have given the veterinarian and the livestock owner a good foundation for a scientific approach to treatment of disease. With a fairly good understanding of what disease is and how Nature tries to overcome it, the veterinarian directs his efforts at assisting Nature. He tries to find out why a heart is beating faster than it normally should, rather than just giving a drug that will slow it down. He looks for the reason when an animal has quit eating, instead of prescribing some medicine that is said to stimulate the appetite. What was once mainly an art has become a science and an art.
DRUGS that act on or affect organs or tissues with which they come in direct contact at the time they are used are said to exert local action.
Drugs that are absorbed into the blood stream and are distributed throughout the body before results are produced are said to be systemic or general in their effects.
Drugs and medicines may be classified according to the actions they produce in the treated animal. Many of the terms used to describe such actions are well known. Stimulant, depressant, anesthetic, blister, irritant, antiseptic, narcotic, and antibiotic need little explanation.
Probably most of the drugs used in treating domestic animals are stimulants. Examples are laxatives or purgatives, which stimulate the bowels; diuretics, which stimulate the kidneys; diaphoretics, which stimulate sweating; and expectorants, which stimulate glandular secretion.
Many drugs have more than a single action. Turpentine is a fairly effective treatment for the coughing that accompanies certain types of laryngitis or pharyngitis, but it is an irritant to the kidneys. Alcohol is a depressant if given internally, but it is a mild local stimulant when it is applied to the skin. Some of the most active of the antibiotics have harmful side reactions, so that they must be used with a great deal of caution.
A few drugs are used as direct replacements for necessary constituents of the normal body. The treatment that is perhaps the most dramatic one in the whole field of medicine the intravenous injection of some form of soluble calcium in a cow with parturient paresis (milk fever) is in this group. As soon as the calcium content of the circulating blood is raised significantly, the cow that is being treated usually shows some response. It is not unusual for an animal that appeared on the verge of death and that probably would have died within a few hours if left untreated to be on her feet in 10 to 15 minutes after the injection is completed. Many of the hormones are in this group, too. Spectacular effects follow the administration of thyroxin, the secretion of the thyroid gland, to animals suffering from thyroid deficiency.
ADMINISTRATION of drugs to farm animals often is a rather serious problem. Theoretically drugs can be given to livestock by any and all the routes that they can be given to human patients, such as by the mouth, by injection with a hypodermic syringe, by inhalation, or by direct application. But there are many reasons why the veterinarian cannot leave drugs for owners to give to their animals by mouth just as the physician leaves medicine for his human patients to take that way.
Perhaps the best way for the average owner to give medicine to his livestock or poultry by mouth is to mix it with feed or salt or give it in the drinking water. But this can be done only in cases in which the animal is taking feed, licking salt, or drinking. It is not very useful in the acutely and seriously sick, which neither eat nor drink. Nor can drugs which have such disagreeable flavors or odors that animals refuse to take them be given in this manner. Sometimes flavors can be disguised by mixing a little blackstrap molasses with the feed, water, or salt. The use of salt as a vehicle for giving such needed elements as iron, copper, cobalt, and iodine now is standard practice. Some worm remedies, particularly phenothiazine, are taken rather readily by sheep and somewhat less so by cattle when they are mixed with salt.
None of the farm animals, except dogs, will take bad-tasting drugs by mouth willingly. They must be given liquids as drenches, with a dose syringe, or by a direct injection into the stomach through a stomach tube. Pills, capsules, and boluses must be placed far back in the mouth if they are to be swallowed.
All of these procedures are time consuming even to a veterinarian who is trained in ways to give medicine.