Mexico weekly ledger., 1904-01-14
BLACK LEG.
How to Know It and How to Pre-
vent It.

NCht 49,
Probably no disease affecting cattle is
more widespread in this and adjoining
states than that which is known to
farmers and stockmen as "~blackleg."
During the year cases of this disease are
reported from nearly every section of the
State. The elevated broken sections, the
fiat prairies, and the lpwlands and
swampy regions all seem alike subject to
outbreaks of this malady. Notwithstand-
ing the wide distribution of this cattle
disease, there are many farmers of long
experience whose herds have never been
attacked by it and who are therefore not
familiar with the symptoms Of the NAL
ady and the proper means of handling it.
Many young men just entering the cattle
business are also unfamiliar with this
disease. 1t is for these readers, mainly
that the present article is written.
The disease affects young cattle vary
ing in age from u few weeks to ten or
fifteen months old. 1t occurs most fire.
q%uently in calves from six to ten months
old, rarely in cattle over eighteen to
t~wenty-four months of age. Calves in
thrifty condition are more liable to an
oeboNh thoh hO ~ bhih
First and Last Symptoms.
About the first symptom that attracts
attention is a slight lameness confined as
a rule to one leg or quarter. There ap-
tibility of the front and hind quarters to
an attack. This lameness which at the
beginning is slight is liable to be mis-
taken for a sprain of the ligaments or
muscles, resulting from some accidental
cause, or a bruise from the horn or head
of one of the older cattle of the herd.
In a few hours the lameness has greatly
increased and a marked swelling may be
observed over the fleshy part of the quar-
ter. The skin over the swollen area is
often very tense and on tapping over this
part with the finger tips g. drumlike
sound is heard. as if the tissues beneath
were distended with air. II firm pressure
is made with the fingers upon the swollen
area, a cracking sound is heard re-
~sembling that caused by crumpling a bit
OF crisp newspaper. The animal be-
comes sluggish, ceases to eat and shows
considerable fever, the nose teing dry
and parched. At the height of the at
tack the thermometer often registers a
rectal temperature of los to LOG degrees.
An hour or more before death the tenn
p~erature falls to 95 degrees or lower.
(The normal temperature varies from
100 to 1927. The breathing movements
are considerably accelerated at the
heighth of the attack. The duration of the
attack from the first appearance of lame
ness until death ensues varies from six
to forty-eight hours. If the animal
showing the above symptoms should live
several days, it is probable that the lame
ness and swelling are due to injury, and
not to an infection that is liable to
spread to other cattle. The animal does
not manifest the symptoms of acute pain
that would be shown if the confusion and
swelling were the results of an injury
from violence.
Examining the Carcass.
II the skin be removed from a calf
that has died from "~blackleg" the mus
cular tissue of the swollen part presents
a b~lackened, bruised "blood-shot" ap-
p~earance, yet the skin which covered this
portion shows no signs Of external in
july. There 10 a striking contrast be-
tween the healthy and the diseased mus
cular tissue, which will attract atten-
ton. In an affected limb, y often oc-
curs that an apparently perfectly
healthy muscle lies alongside, and al
most in contact with, a badly diseased
muscle. If an extensive cut is made across
the affected area So as to expose an end
view of the muscles of the region, the
healthy muscle shows up like a piece Of
flesh from a healthy butchered animal; it
mas a reddish color, is firm in texture,
and in fat calves shows the marbling Of
good edible meat. The diseased muscle
near by is dark in color, often almost
coal-black; the muscular fibres instead of
lying close and compact are spread apart,
giving to the muscular mass a soft,
spongy texture. This condition of the
diseased tissue is the result of the ac-
ton of the "blackleg" germs. During
their growth in the muscular tissue large
quantities of gas are evolved which in a
mechanical way force apart the muscu-
lar fbres, and gives to the tissue its
spongy appearance. Poisonous products
are formed which deprive the blood of
the affected parts of its oxygen; hence,
the Characteristic black color. When a
bit of the diseased muscle is pressed be-
tween the fingers and thumb, a cracking
sound is heard, due to the liberation Of
the imprisoned gas. No disagreeable
odor is emitted from the diseased muscle
If the examination S made soon after
the death of the animal. This is a point
of distinction between "~blackleg" and the
'gangrenous tumors' that result from
extensive bruises of muscular tissue; in
the latter, the odor is very offensive, .
Cause of Blackleg.
As intimated above the essential cause
of the disease is a minute living organ
ism or germ which finds outside the ami