Common Diseases of Farm Animals | Page 6

the chest walls make up for the deficiency. This latter
condition occurs in peritonitis.
A cough is caused by irritation of the membrane lining the air passages.
The character of the cough may vary according to the nature of the
disease. We may speak of a moist cough when the secretions in the air
passages are more or less abundant. A dry cough occurs when the
lining membrane of the air passages is dry and inflamed. This may
occur in the early stage of the inflammation, or as a result of irritation
from dust or irritating gases. Chronic cough occurs when the disease is
of long duration or chronic. In pleurisy the cough may be short and
painful, and in broken wind, deep and suppressed. In parasitic diseases
of the air passages and lungs, the paroxysm of coughing may be severe
and "husky" in character.
The odor of the expired air, the character of the discharge and the
respiratory sounds found on making a careful examination are
important aids in arriving at a correct diagnosis, and in studying the
progress of the disease.
[Illustration: FIG. 5.--Fever thermometer.]
Body Temperature.--The body temperature of an animal is taken by
inserting the fever thermometer into the rectum. In large animals a
five-inch, and in small animals a four-inch fever thermometer is used. It
should be inserted full length and left in position from one and one-half
to three minutes, depending on the rapidity with which it registers (Fig.
5).

The average normal body temperatures of domestic animals are as
follows:
Horses 100.5\° F. Cattle 101.4\° F. Sheep 104.0\° F. Swine
103.0\° F. Dog 101.4\° F.
There is a wide variation in the body temperatures of domestic animals.
This is especially true of cattle, sheep and hogs. In order to determine
the normal temperature of an animal, it may be necessary to take two or
more readings at different times, and compare them with the body
temperatures of other animals in the herd that are known to be healthy.
Exercise, feeding, rumination, excitement, warm, close stables,
exposure to cold and drinking ice cold water are common causes of
variations in the body temperatures of domestic animals.
Visible Mucous Membranes.--The visible mucous membranes, as they
are termed, are the lining membranes of the eyelids, nostrils and nasal
cavities, and mouth. In health they are usually a pale red, excepting
when the animal is exercised or excited, when they appear a brighter
red and somewhat vascular. In disease the following changes in color
and appearance may be noted: When inflamed, as in cold in the head, a
deep red; in impoverished or bloodless conditions of the body and in
internal haemorrhage, pale; in diseases of the liver, sometimes
yellowish, or dark red; in diseases of the digestive tract (buccal mucous
membrane), coated; if inflamed, dry at first, later excessively moist;
and in certain germ diseases a mottled red, or showing nodules, ulcers
and scars.
Surface of the Body.--When a horse is in a good condition and well
cared for, the coat is short, fine, glossy and smooth and the skin pliable
and elastic. Healthy cattle have a smooth, glossy coat and the skin feels
mellow and elastic. The fleece of sheep should appear smooth and have
plenty of yolk, the skin pliable and light pink in color. When the coat
loses its lustre and gloss and the skin becomes hard, rigid, thickened
and dirty, it indicates a lack of nutrition and an unhealthy condition of
the body. In sheep, during sickness, the wool may become dry and
brittle and the skin pale and rigid. When affected with external

parasites, the hair or wool becomes dirty and rough, a part of the skin
may be denuded of hair, and it appears thickened, leathery and scabby,
or shows pimples, vesicles and sores.
During fever, the temperature of the surface of the body is very unequal.
In serious diseases or diseases that are about to terminate fatally, the
skin feels cold and the hair is wet with sweat.
When animals are allowed to "rough it" during the cold weather, the
coat of hair becomes heavy and rough. This is a provision of nature and
enables them, as long as the coat is dry, to withstand severe cold.
Horses that are in a low physical condition, or when accustomed to
hard work, if then kept in a stall for a few days without exercise,
commonly show a filling of the cannon regions of the posterior
extremities. This condition also commonly occurs in disease and in
mares that have reached the latter period of pregnancy. Sheep that are
unthrifty and in a poor physical condition, especially if this is due to
internal parasites, frequently develop dropsical swellings in the region
of the jaw, or neck.
Body Excretions.--The character of the body excretions, faeces