Caseous Lymphadenitis [CL]

by: Dr. G.F. Kennedy

Here we go again. Another disease that appears to be more concern than is warranted along with MISDIAGNOSIS. Sheep and goats get abscesses and a majority of them occur about the head and always in a lymph node. An abscess in a sheep or goat is not necessarily CL, and in our experience usually isn’t. So don’t push the panic button right away and probably never. The CL abscess often has the classically described laminated “onion ring” appearance in cross-section. In goats, the abscess tends to be less organized and can be soft and pasty. Most of the abscesses  we open do not fit the CL description. They are soft and full of pus. More likely Arcanobacter pyogenes or several other bacteria that have made entry.

All of these bacteria including the CL bacteria, Corynebacterium psuedotuberculosis, enter through mucous membrane, skin breaks during shearing  and from contaminated blades, exposure to feed troughs  and equipment where there are breaks in skin. I consider them all infectious versus contagious and obviously there are steps that can be taken to reduce incidence. Feeding correct levels of Iodine in my opinion also reduces incidence.

So if I am a producer and have a sheep or goat with a lump what do I do? Pretty simple, open it, give 10cc of penicillin and do the best you can to isolate it until the skin heals over. That generally means isolating at least two because you shouldn’t pen a sheep up alone. If you encounter the typical CL lesion you need to tighten up your cull practices and cull any that are not doing properly. CL does often locate internally in sheep more so than in goats and may be the reason for poor doers in your flock. Animals with internal abscesses are always terminal it just a matter of time. The older the animal, the higher the incidence.

There is a vaccine available and we don’t recommend its use, it is particularly hard on goats.

Abscesses are important but I would be a lot more concerned about not buying foot rot, preventing abortion, coccidiosis, bacterial pneumonia, E coli scours and a whole lot more. However, it may become a bigger problem in goats than sheep.

CL Doc

internal  CL abscess with characteristic onion like structure

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About Ask-a-Vet Sheep

Veterinary services, procedures, biologicals, and drugs mentioned in this publication represent the personal opinions and clinical observations of the contributing author. They are in no way intended to be interpreted as recommendations without the consent of the producer’s own practicing Veterinarian. We strongly urge that producers establish a patient-client-veterinarian relationship that allows extra-label use when there are no drugs approved for treatment or if approved drugs are not effective. This procedure allows veterinarians to go beyond label directions when “prudent use” is necessary. The limited availability of drugs and biologics in this country is a major factor in restricting the growth of the sheep industry and allowing producers to compete in the world market place.
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