Infectious abscesses are usually caused by a foreign object, such as a splinter or a thorn, lodging under a goat's skin and becoming infected. Injections can also cause abscesses. Sometimes you see a lump that enlarges, or you might just notice the large lump all of a sudden.
Bacteria, such as staph and strep, populate the abscess as the body mounts a defense. If untreated, the abscess can disappear on its own or, more often, it will continue to grow. The outer wall softens until it bursts, releasing a foul-smelling pus. Often the goat loses hair on the site of the abscess.
You can encourage the abscess to ripen by applying hot compresses, or you can lance it with a sharp scalpel. Check it frequently and wait for the outer wall to thin out and make lancing easier. Always wear gloves to prevent contamination; use paper towels to absorb the pus and burn them when you are done. Then put warm compresses on the wound several times a day to aid in healing. You can also put some triple antibiotic ointment on the area.
Infectious abscesses are not a big risk to the rest of the herd if they burst, although they can spread bacteria. On the other hand, Cornybacterium pseudotuberculosis bacteria can develop and infect the lymph nodes and cause abscesses both inside and outside the body. This causes a disease called Caseous lymphadenitis (CLA).
When the external abscesses caused by the bacteria burst, CLA can spread among the herd. It can also be spread by body fluids and when an infected goat coughs. The bacteria can live in soil, on barn walls, and on other objects for years. Although no cure currently exists, you can vaccinate against the disease.
If you discover an abscess that contains thick, greenish material, assume that it's CLA, isolate your goat, and contact your veterinarian for further investigation. The vet can aspirate the contents of the abscess and have them tested by a lab.
You can avoid CLA in your herd by asking the person you're buying goats from whether they vaccinate or have had it in their herd, and specifically in the animal you are buying or its parents. If you find that you have CLA in your herd, separate or remove that goat from your herd because of the risk to other goats.
