United States. Bureau of Animal Industry.

Special report on diseases of cattle and on cattle feeding online

. (page 13 of 56)
Online LibraryUnited States. Bureau of Animal IndustrySpecial report on diseases of cattle and on cattle feeding → online text (page 13 of 56)
Font size
QR-code for this ebook

sory, or afferent nerve, to a nerve center in the brain, and from the cen-
ter the nervous impulse is sent by means of the fibers of the motor, or
efferent nerves, to the various muscles, the contraction of which causes
the forcible expulsion of air from the lungs, which dislodges and ejects
from the larynx the offending particle of food. For another example
the sensation of pain will suffice. If a finger comes in contact with tire
the sensation of paiu is received by the end organs of the sensory fibers
in the skin of the finger, and conveyed to the brain by the seuscry or
afferent fibers, and there is instantly carried by the motor or efferent
fibers to the muscles of the arm the impulse which causes the muscles
to snatch the finger from the fire.

A nerve is a cord consisting of a certain number of fibers, inclosed in
a sheath of connective tissue. This sheath contains the blood-vessels
from which the nerve derives its nutrition. Large nerves are composed
of bundles of smaller ones, each of the smaller contained in its respective
sheath. Nerves divide and subdivide, sending off branches, which
ramify in all parts of the body, and, as they near their terminations,
they contain but one or two fibers.

Nerves are the conductors of the nerve current, or impulse.

The brain and ftpinal cord are contained within a bony canal, which
forms a protective covering for them.

The spinal column consists of a number of bones, especially articulated
or joined one to the other, extending from the head to the tail. Through
each one of these bones the spinal canal is continued.

The spinal cord, or spinal marrow, lodged within the spinal canal, is
continuous with the brain anteriorly, and terminates in a point in the
sacrum (that part of the spinal column which immediately precedes the
tail). The spinal cord is not of uniform size, it being considerably larger
at the part covered by the last two bones of the neek and the first two
bones of the back than it is immediately before or after this enlarge-
ment. It is again enlarged at the part covered by the bones in the
region of the loins.


Along its entire length run two fissures, one above and the other be-
low, exactly in the middle line, nearly dividing the cord in two lateral
halves. The cord is white externally and gray internally. Between
each two of the bones forming the spinal column the cord gives off a
pair of nerves, one nerve emerging from either side of the column. These
nerves (the spinal nerve) arise from the cord by two roots; the superior
root contains sensory fibers, and the inferior root gives the motor
fibers. The union of these roots forms a common nerve, which soon
divides into two branches, containing motor and sensory fibers; the
superior branch to supply the muscles and skin above, and the inferior
branch to supply the parts below, including fibers to form the sympa-
thetic division. The spinal cord conducts nervous impressions to the
brain and impulses from the brain, and is therefore a conductor of
both afferent and efferent currents. It also contains nerve centers, both
reflex and automatic.

The fibers that convey motor impulses decussate or cross from one
side tt> the other in the part of the brain called the medulla oblongata;
therefore a motor impulse going from the right side of the brain crosses
over to the left side in the medulla oblvngata and is carried down the
left side of the spinal cord ; and in like manner, a motor impulse from
the left side of the brain is carried down the right side of the spinal

The nerves that convey sensory impressions go immediately to the
opposite side of the spinal cord ; therefore, an impression of pain re-
ceived on the left hind leg, or any part of the left side of the body, is
conveyed by the sensory nerve fibers to the spinal cord and passes over
to the right side, and is conveyed to the brain by fibers on the right
side of the spinal cord. Thus it follows that if a lateral half of the
spinal cord be cut. all parts posterior to the cut on the same side will
be paralyzed, and ail parts on the side opposite to the cut will be de-
prived of sensation.

The weight of the spinal cord in a cow of average size is estimated
to be 7 1 ounces. The spinal canal is continuous anteriorly with the
cranial cavity.

The cranial cavity, formed by bones of the head, is irregular in shape,
and contains the brain or encephalon.

The brain is continuous with the spinal cord; there is nothing to
mark the place where one leaves off and the other begins. Looking at
the external surface of the brain, on its superior aspect, the larger
mass the cerebrum is seen to be divided by a longitudinal fissure in
the median line into two equal parts, called the cerebral hemispheres,
behind which is a smaller mass called the cerebellum, resting on the
part called the medulla oblongata, which is continuous with the spinal
cord. On the under surface of the brain, between the medulla oblongata
and the cerebral hemispheres, there is a prominent part called the_po*
Varolii, which consists of transverse fibers running across from one


side of the cerebellum to the other. Anterior to the pons Varolii are
two white bundles the crura cerebri. Their continuation with the
medulla oblongata is covered by the pons Varolii; anteriorly they run
"i 1 1 1< > the cerebral hemispheres. At th e anterior part of the fissure which
separates the crura cerebri is the pituitary gland and the tuber cincrcum.
From the under surface of each of the cerebral hemispheres proceeds
anteriorly an appendage called the olfactory lobe.

The arrangement of the gray and white substances of the brain is, to
a great extent, the reverse of that of the spinal cord, the gray being
external and the white internal, except as regards the medulla ob-
longata. in which the gray matter forms centers in its substance.

The average weight of the .brain in cattle as compared to the weight
of the entire body, is estimated as 1 to 860; or, in other words, if the
weight of the animal be 860 pounds, the weight of the brain will be 1

The cranial nerves are given oft* by the brain; they are in pairs, as
follows: (1) Olfactory the nerves of the special sense of smell. (2)
Optic the nerves of the special sense of sight. (3) Oculo-motor sup-
ply impulse to all the muscles which move the eyeball, except three.
(4) Pathetic! motor nerve to the muscle which rotates the eyeball in-
ward and upward. (5) Trifacial nerves of various functions. They
are in three divisions and each division has numerous branches. The
ophthalmic division supplies sensation to the eye and forehead. The
superior maxillary division supplies sensation to the skin of the face, to
tin- membrane within the nose, and gives to the teeth in the upper jaw
tin-ir M-ii^itiwui-^. Tin- in' - i ir in t\ill,i!y !ivi>ion supplies BensatUH
to the teeth in the lower jaw, to the tongue, mouth, and the skin over
the lower jaw. Some of the fibers of this pair aid in supplying the spe-
rm I sense of taste. This pair also supplies motor fibers to the muscles
which move the jaw in the act of mastication. (6) Abducentes motor
nerve to the muscle which turns the eyeball outward. (7) Facial sup-
plies motor impulses to various muscles about the head. (8) Auditory
the nerves of the special sense of hearing. (9) Glosso-pharyngeal
contains motor and sensory fibers to the tongue and pharynx. It also
supplies fibers to aid in the special sense of taste. (10) Piuuimogjvs-
tric sends fibers to the pharynx, larynx, trachea, bronchi, lungs, eso-
phagus, stomach, heart, and many other parts. Its functions are
numerous and important, being both motor and sensory. A branch
gives to the mucous membrane of the larynx its extraordinary sensi-
tiveness, while another branch supplies motor impulse to the muscles
of the larynx. Another branch is the inhibitory nerve of the heart.
Other branches are, thought to participate in exciting the production of
the gastric juice and the bile. The pncumogastric is connected at dif-
ferent parts with the sympathetic division. (11) Spinal accessory
motor nerves, accessory to the pneumogostric. (12) Hypoglossal motor
nerves of the tonjnie, and some fibers to a few other muscles.


The foregoing revifew of the cranial nerves and their functions, brief
as it is, will give a superficial idea of the uses of the nervous system
and the magnitude of its importance.

The meninges are the membranes, three in number, which envelop
the brain and spinal cord, and separate them from the bones which
form the walls of the cranial cavity and spinal canal. These mem-
branes are called the dura mater, external; the arachnoid, middle;
and the pia mater, internal.

The dura mater is composed of very strong and dense tissue. By its
external surface it adheres more or less closely to the bones which form
the walls of the cranial cavity and is continued throughout the whole
length of the spinal canal, but does not adhere to the bones of the
spinal canal to the same extent as in the cranial cavity.

The arachnoid is a serous membrane, and, like all serous membranes,
has two layers, which form a closed sack. The external layer is in con-
tact with the dura mater, and the internal layer is in contact with the
pia mater. The inner surfaces of the arachnoid (the interior of the
sack) are in contact, and are kept moist by the exudation of serum. In
the cranial cavity the external layer is not closely attached to the dura
mater, but in the spinal canal they are closely united.

The pia mater, which is in direct contact with the brain and spinal
cord, is a very thin, delicate membrane, having in its structure many
blood vessels and small nerves. This membrane, being intimately at-
tached to the nervous matter of the brain and spinal cord, follows all
the convolutions, dipping down into the various fissures and inequalities.
The arachnoid does not dip into the inequalities, and consequently
spaces are left between it and the pia mater. These spaces are filled
with a fluid called the subarachnoid fluid, in which the brain and spinal
cord may be said to be immersed. This fluid is of vast importance,
in so far as it, to a great extent, prevents concussion to the nervous
matter of the brain and cord.

The sympathetic, also called the ganglionic, division of the nervous
system consists of two chains of ganglia, reaching from the head to
the tail, situated beneath the spinal column, one on either side. The
presence of the ganglia or enlargements on the cords give them their
chain-like appearance.

As previously remarked, the sympathetic nerves are closely connected
with the cerebro-spinal nerves. In fact, the center for the sympathetic
system is located in that part of the brain called the medulla oblongata,
but the sympathetic nerves are not under the control of the will.
Afferent nerves come from the cerebro-spinal system, as pointed out
when describing the spinal nerves. Efferent nerves go from the ganglia
(or nerve centers) to all the blood vessels, various organs in the neck,
chest, abdomen, etc. The ganglia belonging to the sympathetic system
are numerous, and it is thought by some physiologists that they par-
ticipate in both automatic and reflex acts.



Inflammation of the brain and its membranes is technically termed
encephalitis, but owing to various symptoms, which no doubt depend
much on the particular part affected, the disease is known by different
names, such as staggers, stomach staggers, mad staggers, sleepy stag-
gers, coma, frenzy, etc.

Inflammation of the nervous matter comprising the brain, without in-
volving the membranes, is a rare disease in cattle, so much so that few
authorities notice it as a distinct affection, and then only to point out
the fact that it is discovered by post-mortem examination. There are
no symptoms exhibited by which it may be positively distinguished
from encephalitis the disease involving the membranes as well as the
brain and therefore it will be included in this description.

Causes. Severe blows on the head with a hard object, or the head
coming violently in contact with the ground or other hard substance
in a fall, may be followed by encephalitis. Irritation caused by tumors
in the brain may produce inflammation. Food containing deleterious
matters, for example, ergot (see Plate V) and other fungi which con-
tain a narcotic principle, is the most frequent cause of this affection,
and hence it is often called " grass staggers " and " stomach staggers."
In many localities certain plants have the reputation of causing stag-
gers. As, for instance, u Elliott's Botany of South Carolina and
Georgia," edition of 1821, says : u Atamasco stagger- grass. Gener-
ally supposed to be poisonous to cattle and produces the disease in
calves called staggers." The writer "can not say that this particular
plant (Atamasco Lily Amaryllis atainasco, L.) produces the disease,
but he quotes the supposition to add strength to the point that it is
generally believed that certain plants do cause it. European authors
<l-M-ribe a variety of the disease "arising from the consumption of the
refuse of distilleries." When the disease is not caused by direct vio-
lence the quality of the food should be suspected.

fiymptoms. The symptoms vary much, but a careful observer will
detect a trouble connected with the nervous system without much un-
certainty. The first signs may be those of freii/y, but generally at the
start the animal is dull and sleepy, with little or no inclination to
move about ; the head may be pressed against the wall or fence and
the. legs kept moving, as if the animal were endeavoring to walk through
the obstruction ; the body, especially the hind part, may be leaned
against the side of the stall or stable, as if for support. The bowels
are constipated ; the urine, when passed, is small in quantity ami
darker in color than natural. There may be trembling and even
spasms of muscles in different parts. In the dull stage the animal may
breathe less frequently than natural, ami each breath may be accom-
panied with a snoring like sound. The pulse may be large and less fre-
quent than normal. If suddenly aroused from the drowsy state the


' ;i>t appears startled and stares wildly. "When moving about the an-
imal may stagger, the hindquarters swaying from side to side.

When the delirium ensues the cow is commonly said to be mad. She
may bellow, stamp her feet, run about wildly, grate the teeth, froth at
the mouth. If she is confined in the stable, she rears and plunges;
the convulsions are so violent in many instances that it is really dan-
gerous for one to attempt to render aid. The body may be covered
with perspiration. She may fall; the muscles twitch and jerk; often
the head is raised and then dashed against the ground until blood
issues from the nose and mouth; the eyes maybe bloodshot and sight-
less; the limbs stiff and outstretched, or they may be kicked about
recklessly; the head may be drawn back and the tail drawn up; the
urine maybe squirted out in spurts; often the "washer" (membrane
nic titans) is forced over the eye. When the convulsions cease they
may be followed by a period of quiet unconsciousness coma which is
more dr less prolonged, when the animal may gradually regain con-
sciousness, get up on its feet, and perhaps quietly partake of food, if
there be any within reach, while at other times it arises with much dif-
ficulty and staggers blindly about the stall or field.

It must be remembered that all the foregoing symptoms are not
always seen in the same case. In those cases usually designated sleepy
staggers the general symptoms of drowsiness are presented, while in
other cases the symptoms of frenzy cause the affection to be called mad
staggers. In other cases, when the spinal cord and its membranes are
more or less involved, there are symptoms of paralysis, swaying of the
hindquarters, inability to rise, etc.

The various symptoms increase in frequency and intensity until they
end in death, which is almost invariably <he result of an attack of en-
cephalitis in cattle.

It is well to remark that when the disease follows injuries to the
head, the symptoms may not be manifested until two or three days (or
longer) after the accident.

Treatment. For reasons which are obvious from the description of
the symptoms, treatment of this disease is anything but satisfactory.
Recoveries are rare in spite of careful scientific attention, even in those
cases which are under the most favorable circumstances. To be of any
service whatever the treatment must be prompt and begin with the
disease. In the early stage the pulse is large, and in most cases will
admit of bleeding. Eight or nine quarts of blood should be taken from
the jugular vein. This should be followed immediately by a purgative,
the following, for a cow of average size: Epsom salts, 24 ounces; pul-
verized gamboge, ounce; croton oil, 20 drops; warm water, 3 quarts.
Mix all together and give at once, as a drench.

About 2 quarts of warm water or warm soapsuds should be injected
with a syringe into the rectum (last gut) every three or four hours. It
is best to keep the animal in a quiet, sheltered place, where it will be


free from noise or other cause of excitement. All the cold water the
animal will drink should be allowed, but food must be withheld, except
bran slops occasionally in small quantities, or grass, if in season, which
may be cut and carried fresh to the patient.

During the convulsions all possible efforts should be made to prevent
tin- animal injuring itself; the head should be held down on the ground
and straw kept under it. Cold water may be continuously poured on
the head, or bags filled with ice broken in small pieces may be applied
to the head. Different authors recommend different remedies to allay
the convulsions, but for two reasons it will be found extremely difficult
to administer medicines during the convulsions: (1) While the animal
is unconscious the j>ower to swallow is lost, and therefore the medicine
is uiore liable to go down the windpipe to the lungs than it is to go to
the paunch. (2) The convulsions are often so violent that it would be
utterly useless to attempt to drench the animal. And furthermore it
must be borne in mind that during this stage the functions of digestion
and absorption are suspended, and as a consequence the medicine (pro-
vided it finds its way to the paunch) is likely to remain there un ab-
sorbed and therefore useless.

A blistering compound, composed of mustard, 1 ounce; pulverized
c MMtharides, one-half ounce; hot water, 4 ounces, well mixed together,
may be nibbed in over the loins, along the spine, and back of the head
on each side of the neck. This is occasionally attended with beneficial
effect, and especially so in those cases when paralysis is present.

If the purgative acts, and the animal shows signs of improvement in
th- course of two or three days, 2 drams of iodide of potassium may be
a every night and morning, dissolved in a half bucketful of drink-
ing water, if the animal will drink it, or it may be dissolved in a half
pint of water and given as a drench. Great care must be observed in
regard to the food, which should be nutritive but not coarse, and at
first in small quantities, gradually increased as the patient improves.
After soiue progress is made towards recovery 1 drams of pulverized
mix vomica may be given twice a day. added to the iodide of potassium
drench. This should be administered so long as a staggering gait con-

In those rare caeea when recovery takes place, it is only partial as a
rule, as there is generally a sequel which remains, such as partial pa-
ralysis; however, this is but a slight drawback in cattle, because when
it is seen to persist, the medicine should be stopped and the animal
fattened for butchering.

Postmortem examinations discover congestion of the brain and its
membranes. The pin mnlrr (the vascular membrane) is most congested.
In those cases which have exhibited much paralysis before death, the
pin mater of the cord is congested in the lumbar region (loins). When
the disease has been causod by injury to the head tlie congestion and
extmvasated blood may bo found inside of th<> ravitv in the location


corresponding to the place where the injury was inflicted externally.
In some cases pus is also discovered. It remains to be said that in all
animals that have died from this affection the lungs are found very
much congested. This leads the nonprofessional to suppose that the
disease was a lung affection, but in fact it is only a natural consequence
when death ensues from brain disease.


That form of congestion of the brain known as parturient apoplexy,
which is so frequently associated with the period of calving, is described
in another part of this work. (See Parturient Apoplexy, p. 2-47.)

Cerebral apoplexy, not connected with parturition, is a rare disease
among cattle. However, it may be due to degeneration and consequent
rupture of a blood-vessel in the brain ; the pressure of the blood which
escapes from the ruptured vessel upon the nervous substance causes
the alarming symptoms.

The attack is sudden, the animal in most cases falling as if hit on the
head with an ax. Convulsions similar to those described as symptoms of
encephalitis may ensue, or the unconsciousness may not be accompanied
with any movements of the head or limbs; the eyes are open and
blindly staring, the mouth frothy, the body cold; the breathing may be
loud or snoring, the pulse frequent and small. There may be remis-
sions in the severity of the symptoms, but the pressure from the con-
tinued escape of blood soon causes death.

There is described a form of congestive apoplexy, affecting cattle
which are in a plethoric condition. The congestion, or superabundant
quantity of blood in the vessels of the brain, may be followed by rup-
ture of the vessels. It is said to occur mostly in hot weather. In this
variety the symptoms given are somewhat similar to those exhibited
when the affection is due to degeneration of the blood vessels, but
not so violent; the animal may show premonitory signs, such as dull-
ness, staggering, and may only fall to the knees, the muzzle resting
on the ground.

In such cases bleeding should be resorted to immediately, and when
the power of swallowing is not lost purgatives should be administered.
Cold applications to the head, and the general treatment recommended
for encephalitis are indicated.


Severe blows on the head, striking the head against some hard ob-
ject while running, or falling on the head, may cause concussion of the
brain. The injury may fracture bones of the cranium and produce com-
pression of the brain.

The symptoms vary according to the severity of the concussion. After
receiving the injury the animal may lie prostrate, entirely unconscious


of all surroundings, with complete loss of sensation and power; how-
ever, there may be some slight convulsive movements, but they are
without any effort of the will.

Death may quickly follow the injury; or, if the injury has not been
very serious, recovery may take place in a comparatively short time; or
the animal may linger in a more or less unconscious state for a consid-
erable time, or there may be a partial recovery from the injury, followed
within a few days by encephalitis.

The injury which produces concussion of the brain may at the same
time fracture one or more of the bones of the cranium. The fracture
may be simple a crack in the bone without depression, or the broken
bone may be depressed, the pressure on the brain substa-uce constitut-
ing compression of the brain. The first step in the treatment of com-
pression of the brain from the latter cause is to elevate the depressed
bone, which in some cases may be done with a thin but strong piece of
steel, like a knife blade. In many cases it is necessary to remove a
portion of bone with a trephine in order to be able to raise the depressed
part. Such cases require the skill of an expert veterinarian, but un-
less the animal is a yery valuable one it should be butchered as soon as
possible after the accident, and not allowed to linger until the meat
becomes unfit for consumption.

Compression of the brain may result from an injury without fracture

Online LibraryUnited States. Bureau of Animal IndustrySpecial report on diseases of cattle and on cattle feeding → online text (page 13 of 56)