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Anaphylaxis
in Cattle
Randall
J Berrier, DVM
Staff Veterinarian
Technical Service
In
the late winter and early spring of the year, cattle ranchers
begin to band or castrate, brand, dehorn and vaccinate for a
variety of different diseases.
Cattle are injected with many different substances -
antibiotics, vaccines, bacterins and toxoids to name a few.
All of these substances are observed as
"foreign" by the animal's immune system, and this is
what we hope to achieve through vaccination.
The animal's immune system will develop antibodies
and/or cell- mediated immunity to combat these foreign agents
in the future when they may be encountered through natural
exposure.
The vaccine generates an immune response without
creating illness.
On
very rare occasions cattle can develop an acute allergic
reaction to a foreign substance that has been injected into
its body.
These reactions can range in severity from hives and
itching to systemic shock with pulmonary edema (fluid in the
lungs) and death.
This most severe reaction is called anaphylactic shock.
Again, this syndrome is rare.
It has been estimated to occur in less than one animal
per 10,000 in cattle.
However, cattle do seem to be the most susceptible
among our domesticated species.
It
is not uncommon to see a group of calves develop anaphylaxis
when it does occur.
This can happen in calves just a few weeks old.
This is because these calves have been raised together
and exposed to the same environmental sensitizing antigens.
These sensitizing antigens are proteins and can be
bacteria, viruses, molds, fungi, antibiotics or components in
the antibiotics or other injectables or maybe something in
their feed.
There also may be a genetic link in some breeds of
cattle making them more susceptible to anaphylaxis.
When first exposed to these sensitizing proteins, the
animal's immune system will develop antibodies over a certain
amount of time (days to weeks).
When the animal is exposed again, through vaccination,
to the same antigen it was sensitized to, the allergic
reaction occurs.
When an entire group of calves react it is only because
they have all had the same sensitizing exposure and the same
period of time for sensitivity to develop and the same type of
shocking dose (i.e. vaccination).
Anaphylaxis
usually happens within 10 to 20 minutes from the time of the
injection.
It can take up to two hours for anaphylaxis to show up.
Many animals do survive anaphylaxis, but in severe
cases animals can die very quickly.
The target organ in cattle is the lung.
The first symptoms noticed are increased respiration
rate and muscle fasciculation's (tremors).
As conditions worsen, the animal's lungs fill with
fluid and they will breath with their mouth open and their
tongue extended out.
They often times will walk backwards, trying to take
deeper breaths.
In advanced stages you can hear moaning and bloody foam
will come out of their mouth and nose, followed by collapse
and death.
It
is very important to treat these animals when symptoms first
appear.
Epinephrine (1/100) subcutaneously at a dose of 1cc per
100 lb. of body weight is the drug of choice and can literally
be a lifesaver.
A second dose can be given in 15 - 20 minutes if
needed. In
addition Flunixin Meglumine (50 mg/ml) can be given at a rate
of 1to 2 cc per 100lb. intravenously or intramuscular as well.
Consult with your veterinarian about the use of these
drugs.
It is a good idea to have these drugs on hand when
vaccinating cattle and to keep cattle confined and observed
for a while after vaccinating for signs of anaphylaxis.
This
article is certainly not intended to discourage the use of the
many excellent products available for preventing and treating
various livestock diseases.
The valuable efficacy of today's vaccines, toxoids,
bacterins, antibiotics and serum products far outweigh the
risk of anaphylactic shock.
When one is aware of what might occur and knows what
measures to take to counter act it, then there is certainly no
reason to be overly concerned.
Also,
in spite of the normal inclination to blame a drug or vaccine
for a reaction, one should keep in mind that a product's
manufacturer has no control over this phenomenon and that it
does not spring from any manufacturing defect in the products
themselves.
Reference:
Farm Supplier, March 1982, Animal Health, page 51 by J.
Calvin Downing, DVM, |
