The Meaning of Disease
Any departure from a normal condition is disease. The body, composed of
different organs and parts, is in a healthy state when each of these
performs its natural functions. Thus the normal mind is concerned with
normal mental acts; any disturbances of the brain or spinal cords is
immediately manifested in the action of the animal; likewise frequently
a disturbance elsewhere may later have its effect on the mental system.
Disease may result from some external cause like from a wound, from food
causing poison or derangement of the digestive system, from water
introducing impurities, from parasites that disturb normal functions,
disorganize tissue or produce toxines, or from other abnormal
conditions--all of which interfere with the normal functions of one or
more organs, regions, or parts.
In most cases the disturbances are readily recognized. Swellings,
bruises and wounds are located at a glance. When blood passes from nose,
ears or intestines, a key to the trouble is at hand. Coughs have their
story. And vomiting, diarrhœa, convulsions, spasms, abnormal breathing
or temperature each indicates at what points an abnormal condition is
evident.
=Disease, Both General and Local.=--Some diseases lead to disturbance
throughout the entire body. For instance, pus may accumulate at some
point from which it finds its way into the blood, in the end reaching to
other parts of the body that in time also become affected.
Those diseases, with which fever is associated, are general in nature.
The nerve centers are influenced, the body heat is increased and a
weakened condition prevails. Back of this are the disease
poisons--chemical poisons or germ poisons.
When the temperature of the body, as a result of fever, rises too high
certain life principles are changed and death immediately follows. A
temperature of 106° or 107° is very high, and, therefore, very
dangerous. In treating disease the temperature is watched, that the
course of the fever may be followed. Treating a fever, then, is helpful
and a natural part of the treatment of the disease itself. The basis of
the curative process rests upon the principle of proper circulation and
the excretion of the impure substances.
CAUSES OF DISEASE
In the first place most diseases arise from mismanagement. The very
principles at the bottom of good health receive no consideration and
little thought. On some farms it is seldom that a case of disease is
heard of; on others, stock are under treatment at all times. Where order
prevails, where cleanliness is appreciated, where disease-producing
conditions are never allowed to accumulate or even gain an introduction,
health is the rule and disease the exception. When the latter appears,
it is due to some outside influence that gave it admission.
The greatest mischief in handling farm stock comes from improper food,
filthy or impure drinking water, bad ventilation of stables, overwork,
or lack of exercise and poor sanitary conditions.
Disease, therefore, is largely due to causes within control of the owner
of the farm stock. True, one source of trouble is due to mechanical
causes: horses get nail punctures, legs and necks and head are cut in
fences, blows bring bruises. But whose fault? Certainly not the animal.
Old boards with nails ought not to be left in all sorts of places,
fences should be protected, and stable fixtures, gates and harnesses
should be in such order that only in rare cases will injury result.
=Disease from Chemical Causes.=--Poisonous materials and poisonous
plants cause death to thousands of animals annually. Of great importance
to the stock interests is the rapid destruction of these harmful
products. Fortunately in the older sections these are about eliminated
now, and we are also understanding more about the molds that lead to bad
results when moldy forage is given as feed to farm animals. In time
disease will be considerably lessened when only clean, wholesome food
finds its way into the mangers and feed racks--then disease will depart
and more rapid gains will come.
=Heredity Plays a Part.=--Despite caution and care, health is often
disturbed because of hereditary influences. Thanks to science, we know
now that many of the old bugbears of the past, and once so entrenched,
have become dislodged, and their true import set right before the owner.
Tuberculosis, for instance, once so dreaded in both man and beast, is
now known not to be handed down from parent to progeny; it is a germ
disease, pure and simple, and gets its start just as many other
ailments--through breath, or drink, or feed. There are hereditary
troubles, however, that continue down through many generations. The
narrow hock of the horse invites curb diseases; the narrow chest is a
good breeding ground for tuberculosis germs; straight pasterns are bad
for the feet; poor conformation is not consistent with efficiency or
easy functional activity.
These examples clearly show that form and type and physical
characteristics have roles to play in animal economy and in health to
which the wise stockman will give heed.
[Illustration: BACTERIA AS SEEN UNDER THE MICROSCOPE
_a_, Spirillum. _b_, Micrococcus. _c_, Micrococcus. _d_, Streptococcus.
_e_, _f_, _g_, _h_, Rod-shaped bacteria. _i_ and _j_, Divisions.]
=Germs and Parasites.=--In addition to the above causes of disease,
another class is before us ready to inflict its injury at all times.
Indeed, it is a class of the greatest importance. I refer now to
parasites, bacteria, and germs, which cause more loss to live stock than
all others combined. Think of hog cholera, a germ disease; of
tuberculosis, a germ disease; of stomach worms, parasites; of staggers,
a mold disease; of abortion, a germ disease; and hundreds of like
nature, all due to parasites and germs, disease agents that disturb and
destroy the delicate organs or exposed regions, as the case may be,
regardless of age, value, or breed.
Of course, remedies and treatment are being worked out to meet these
individual diseases as they occur. Nevertheless, the best treatment is
prevention. It is far better to prevent than to cure; and that is the
line of action especially for this class. Indeed, it is far easier to
understand the simple laws of prevention than the complicated curative
processes. Especially is this true since germs are known and isolated,
and their rapid destruction with air, sunlight, and disinfectants
understood and available.
ORIGIN OF DISEASE
Enough has now been said to indicate that disease originates as a
reaction between the cause of it and the body. Withhold food, and
starvation--the disease--follows. Withhold fresh air and oxygen, and the
tissue breaks down; disease results as a reaction from the normal use of
air and the demands of the body for oxygen. Allow bacteria admission to
the body and settlement in the tissues or organs most agreeable to each
particular one, and these will grow, multiply, and, unless overcome by
the natural resistance of the body, will conquer and destroy, causing
sooner or later death and decay.
=Immunity Sought by Inoculation.=--Many diseases that now yield to no
curative treatment are being met by inoculation. By this method the body
is reinforced by serum injections, that disease germs and infections may
be warded off, or in case of attack, be so fortified against the disease
germs as to destroy them or render them inactive.
=Some Animals More Resistant to Disease.=--An infectious and contagious
disease may affect a herd or flock, destroying few or many. Some may
never be affected and yet be subjected to exposure and contagion; such
are immune and resist this particular disease. Others may suffer a mild
attack, but throw it off with no disastrous consequence; such are strong
and their organs ably fortified against any injurious inroad by the
disease. On the other hand the majority in a flock or herd is not so
able to throw off the disease for the reason of being predisposed by
nature to such attacks; their very susceptibility invites attack, and if
the infection is intensely virulent the affected body will most likely
yield and death follow.
THE COURSE OF DISEASE
Each disease possesses its own peculiar characteristics, which are more
or less conspicuous in each individual case. Then, too, some diseases
develop quickly and end quickly. Others run a course of several weeks;
and still others several months or even years. The first class is acute,
the second chronic. In both kinds nature is at work endeavoring always
to effect a cure; and, unless other complications arise, the result of
improper food, bad sanitary quarters, bad air, or conditions not
conducive to health, recovery will, in most cases, result. The great
drawback to rapid recovery comes from the outside influences that
counteract the curative processes of the body itself. Good nursing, good
air, proper food, are back of rapid recovery.
Most diseases have been carefully studied, and their course of
development has been mapped out. Our veterinarians know, in a general
way, how fever acts in live stock. If an animal is inoculated with
Texas fever germs, the veterinarian knows the course of the disease
beforehand. In a general way, he knows when the fever will begin, how
long it will last, when it will be at its highest point, and when it
will disappear. He knows all of this, even before he makes the
inoculation. Yet no disease invariably runs the same course in different
individuals. In fact, the virulence of bacteria have much to do with the
course; mild cases occur usually when the germ is weak, and severe cases
when the germs are very virulent. This explains why some attacks of
measles or Texas fever or hog cholera are more fatal than other attacks
in other places, or at other seasons of the year.
=Typical Courses the Rule.=--It is in rare cases only that a regular
course is not followed by most diseases. Take an infectious disease. The
period of incubation comes first; this follows up the infection. During
this period, no change in the animal is observed. He seems well, acts
well, and does his work well. Nevertheless, all the time, during this
period of infection, the germs are developing, multiplying, gaining
headway, and so entrenching themselves that illness and disorder will
soon follow. The period of infection varies in different animals and in
different diseases. It may take two or three weeks for development, or
as few as two or three days.
Following the period of infection comes the period of eruption. At this
stage the typical characteristics are observed. At the next step the
disease reaches its height with the animal under its complete dominion.
But only temporarily. If properly nursed and treated, with most
diseases, the animal will pass through the period and recover.
The final stage is the period of improvement. The battle that has been
waged between the body and the disease is now about ended. The disease
germs have been routed and the body has been victorious. All that now
remains is the clearing away of the débris. In this case it is scattered
throughout the body system. The damage that has been done is to be
repaired and left, if possible, as near to the original condition, as
the nature of the disease will allow. The period of improvement will
vary in different diseases and in different animals. Recovery may occur
in a few days, in some cases, and in others weeks and months will be
required. A change of feed or pasture or work is usually necessary if
the most rapid recovery would be had. In some cases, nothing other than
absolute rest will suffice.
THE TERMINATION OF DISEASES
After the disease has run its course, the body usually returns to its
former normal condition. There seems to be a limit to what the disease
can do. A healthy body may be attacked, but, in the end, disease
retires, having used itself up. There are diseases, however, that leave
their marks in many ways. And these become permanent marks. With many of
these all of us are acquainted. Smallpox is one. The pits over the face
record the fierce battle that was fought. The same is true of wasted
tissues, with scars that conspicuously mark the track along which blood
poison has traveled. The shrunken hoof of the foundered horse tells the
adverse termination of that disease.
While recovery may be more or less complete, the effect is to seriously
injure the worth and value of the individual. There is a long list of
this kind.
[Illustration: RESULT OF BONE SPAVIN
Pictured here is a natural hock free from disease and a diseased hock,
the result of bone spavin. The bone is seriously affected and the easy
action prevented.]
Other diseases act differently in another way. They progress slowly, are
not noticeable at first, but in the end are incurable. Take glanders as
a typical case. It quietly and silently develops, often taking months or
years in reaching the stage of eruption or before it becomes apparent.
During all this time, and even after the disease is recognizable, the
animal goes on about his duties with no apparent trouble. The disease,
however, is progressing all the time; in the end it conquers its victim,
the final stages are reached, and the animal dies.
The stock raiser is concerned with different diseases in so far as they
mean slow or rapid recovery, and particularly if they be contagious or
not. His entire herd will be impaired if glanders is introduced into it.
One tuberculosis cow will convey the disease to all susceptible
individuals in the herd to which she belongs, especially if stabled in a
tight barn during the winter seasons when little or no ventilation is
intentionally provided.