12/08/2024
SHOULD WE WORRY ABOUT ABSCESSES?
by Susan Schoenian
Sheep & Goat Specialist Emeritus
University of Maryland Extension
It is not uncommon for sheep and goats to get abscesses. Some producers cull every animal that gets an abscess. Others disregard them. But what is the right thing to do?
An abscess is an accumulation of pus surrounded by fibrous tissue. They may occur anywhere in the body where pyogenic (pus-forming) bacteria can establish and multiply. Over time, pus is mostly replaced by fibrous tissue.
In sheep/goats, abscesses have different causes and can be the result of different bacteria; 23 different bacteria were identified in a 1980 study. An animal can get a hoof abscess when crud gets packed into a pocket in its hoof. Subcutaneous abscesses can occur at vaccination or injection sites. Abscesses in the cheek and jaw occur when the skin is penetrated by a thorn or other sharp object during feeding or rubbing. A few years ago, I had a ewe with an abscess in her throat.
The most serious abscesses are those caused by the bacteria Corynebacterium pseudotuberculosis. This is the disease called caseous lymphadenitis or just CL. It is also called “cheesy gland” because of the “cheese-like” appearance of the pus. CL abscesses can be internal or external. The external form is found more commonly in goats and presents as abscesses in the peripheral lymph nodes.
External abscesses are found mostly behind the ears, beneath the jaw or neck, on the shoulders, or in the rear flank region. The internal form of CL is more common in sheep. Wasting can occur when the internal abscesses interfere with normal organ function. CL has been associated with “thin ewe syndrome.”
Animals infected with CL are infected for life. There is no cure. Antibiotics have no effect on the bacteria that causes CL. With that said, abscesses should be treated to prevent ruptures and further contamination of other animals and the environment. They can be surgically removed or drained, with the latter being more common. After draining, abscesses should be washed with hydrogen peroxide and flushed with iodine.
An animal with an abscess should be quarantined until the abscess has completely healed and the causative organism has been determined. Not all abscess are CL. In our buck test (2006-2016), only about half of the abscesses we tested were CL. Every abscess I have ever tested on my own farm has been non-CL.
To keep CL out of your flock/herd, you should avoid purchasing animals with any signs of abscesses. Quarantine all new animals prior to joining them with other animals on your farm. There is a CL vaccine for sheep. It is recommended that it not be used on goats. Nor should it be used in naïve flocks.
CL can be eradicated by culling all animals with abscesses (or testing the abscess material to make sure it is not CL; cull if it is) and removing any animal from the flock/herd that blood tests positive for CL antibodies. Alternatively, infected and uninfected animals can be separated.
There’s no reason to take a chance with CL and to be a reason for its continued presence in the sheep/goat industry.
Published May 2023 in the Delmarva Farmer.
