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Veterinarian's
Corner |
Randall J Berrier ,DVM
Staff Veterinarian
Technical Service
CLA in Goats
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Colorado Serum Company
often gets a lot of correspondence regarding caseous lymphadenitis (CLA) in
goats and questions about using our CLA vaccines (Case-Bac and Caseous D-T)
in goats. There seems to be a lot of interest and misleading
information regarding vaccinating goats against CLA.
For more detailed information about CLA, the disease, please refer to
our vet's corner from June 2001, (volume 1 - no.4).
Caseous lymphadenitis is
caused by the bacterial organism Corynebacterium pseudotuberculosis.
The two vaccines that Colorado Serum Company makes for CLA are
licensed for use in sheep only. These
two vaccines are also the only two commercially available vaccines for
combating CLA in the United States. The
vaccine (Case-Bac) is a combination bacterin/toxoid, while Caseous D-T also
contains tetanus toxoid and Clostridium perfringens type D toxoid as
well.
The main reason why
Colorado Serum Company did not have a label for usage of these vaccines in
goats is safety. Colorado Serum Company originally tested caseous vaccines in
goats and noted varying levels of injection site reactions that went from no
reactions to swellings about 14 inches in diameter. There would be associated lameness post-vaccination that
would last anywhere from 1 to 30 days.
All of these reactions would be unacceptable to USDA and therefore
Colorado Serum Company never pursued a license in goats.
Since Colorado Serum Company was unhappy with the safety profile of
these vaccines in goats, we never pursued any further efficacy testing in
goats. Over the years Colorado
Serum Company has also received numerous calls from the field from people
who have used this vaccine off label in goats.
A fair percentage of vaccinated goats will develop a fever and become
lethargic for a period of days. These
goats will sometimes go off feed or have a reduction of feed intake.
Milking does can have a decrease in milk production.
Vaccinating pregnant animals can increase the risk factors.
As in sheep, vaccinating goats that already have CLA will do
absolutely no good and will only make the above-mentioned reactions worse.
So you can see why we cannot recommend vaccinating goats with these
vaccines.
However, all hope is not
lost. There are other options for goat ranchers.
First of all, I would strongly recommend having any suspect abscesses
sampled by a veterinarian and submitted to a veterinary diagnostic lab to confirm
if your herd has CLA. An
article by Gezon, Bither, Hanson and Thompson in the Journal of the
American Veterinary Medical Association 1991; 198:257-263, reported that
over a 16 year period Actionmyces pyogenes was cultured 3 times more
often than C. pseudotuberculosis in a particular goat herd with an ongoing
history of internal and external abscesses.
The point is - not every abscess in goats is CLA!
If you confirm that you do indeed have CLA in your goat herd I would
recommend not treating goats that have abscesses and either selling them or
isolating them. Since there is no commercially available vaccine available
for goats you may want to consider having an autogenous vaccine made from a
sample of one of the abscesses that tested positive for CLA. Most autogenous products are whole-cell bacterins.
It has been our experience that a bacterin/toxoid provides a much
better immune response. I don't
know how much protection goats are going to receive from an autogenous
bacterin. You may want to try
an autogenous caseous bacterin in a limited number of goats and determine if
it works in your goat herd.
Hopefully this helped answer questions about using Colorado Serum Company Case-Bac and Caseous D-T vaccines in goats and why Colorado Serum Company can't recommend it. Currently, Colorado Serum Company is actively pursuing a safer vaccine for CLA that can be licensed for use in goats.