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CASEOUS LYMPHADENITIS (CL) AND THE TEXAS VET LAB VACCINE FOR GOATS

Caseous Lymphadenitis (CL) is a contagious bacterial infection affecting goats (and sheep). The organism corynebacterium pseudotuberculosis infects the animal through wounds caused by head butting, punctures, and shearing, as well as oral ingestion of the pus (exudate) from a ruptured abscess. The lymph system filters the bacteria from the goat's body and pushes it into a thick-walled (encapsulated) abscess so that it can't harm the goat. Visible abscesses usually don't appear for months after infection. CL abscesses are seldom seen in young goats because its immune system isn't fully functional until the animal nears one year of age and the lymph glands can't filter something that the immature immune system hasn't recognized. For the same reason, blood testing for CL can be inaccurate in goats under about eight months of age. Although I've helped many goat raisers with CL in their herds, I've never seen CL abscesses on a meat goat under six months of age. Unlike CAE and Johnes, CL is not transmitted through milk, saliva, semen, or other bodily fluids.

CL is not the disease equivalent of CAE or Johnes. Too many people classify these three diseases as equals. They are not. CL is manageable and we have a vaccine for it. At this time, nothing is available to manage CAE or Johnes. Goats with CAE or Johnes must be culled and that means go to slaughter. Not so with CL. People become irrational when they see an abscess, often assuming every abscess is CL. That isn't true. There are many kinds of abscesses. The presence of external abscesses doesn't mean that the goat has internal abscesses. This is seldom true in goats but is common in sheep. When a CL abscess is mature and ready to lance, it is attached to the inside of the hide rather than the goat's body. I have detailed articles on how to handle a CL abscess. I no longer recommend injecting Formalin because people don't use it correctly. Lancing the abscess, removing the pus, flushing with iodine, and vaccinating with the TVL vaccine for CL in goats is the best protocol.

CL is much more likely to be spread among goats kept in close quarters and/or over-crowded conditions. All breeds of goats can catch CL. Vectors for spreading the bacteria include insects, birds, wild animals, domestic pets that are allowed to roam outside, needles, eartaggers, scissors, feed troughs (especially wood troughs), and clippers. CL can be brought in on the shoes (and clothing) of visitors. Always use a disinfecting mat for the footwear of all visitors. Jeffers sells a disinfecting mat (item #WEBAPDA) and disinfecting liquid for use with this mat that I use. No one knows how long pus from ruptured abscesses can stay in hay, soil, and equipment. Hot and dry weather kills the bacteria faster than wet and/or cold. The disease is not painful to the goat but is an management nuisance to goat raisers. Although considered "incurable," CL is readily managed.

In May 2012, Texas Vet Lab of San Angelo, Texas announced US Government approval of its new vaccine to protect goats against CL. My herd was one of three that participated in the vaccine's field trials in summer 2011, the results of which were submitted to USDA for vaccine's approval. Texas Vet Lab then sent it licensing information to all 50 state vets in the USA, and the terms under which it can be used in each state is on its website www.texasvetlab.com under the link "CL State Approval List." Jeffers, the livestock mail order house that I've used and recommended since the early 1990's, carries the vaccine and is the best place to buy it. Call 1-800-533-3377 or go to www.jefferslivestock.com.

The vaccine is not approved for use on pregnant or lactating does or kids under three months of age (or with sheep). That doesn't mean it is unsafe; it simply means that testing was not done on these groups of animals. My personal opinion is do not use this vaccine on pregnant does because they don't need any added stress and don't use it on goats under eight months of age because of their immature immune systems. I give this vaccine alone and never in conjunction with other vaccines in order to minimize reactions. It is an extremely effective vaccine which should be used on all goats, even if they have been diagnosed with CL, but it has short-term side effects that can be minimized by careful administration. My article entitled "Caseous Lymphadenitis: Misconceptions About the Disease and the CL Vaccine" revised December 2015 explains how I use this vaccine and why.

The CL vaccine must be kept refrigerated and is very sensitive to temperature changes. Do not allow it to freeze or get hot. Shake before each use. If the bottom of the bottle is brown, throw it away. Normal liquid separation occurs at the top of the bottle.

As a long-time goat producer, I am grateful that Jim Bob Harris, owner of Texas Vet Lab, chose to develop this much needed vaccine for a species that is few in number and therefore not a big profit center. Diligent use of this vaccine by goat raisers can largely eliminate and definitely control this disease in goats in a relatively short timeframe.

Suzanne W. Gasparotto, Onion Creek Ranch, Texas 12/3/15

CASEOUS LYMPHADENITIS
Misconceptions About the Disease and the CL Vaccine

In May 2012, Texas Vet Lab, Inc. of San Angelo, Texas announced the US government approval of its new vaccine to control Caseous Lymphadenitis in goats. Since that announcement, questions have arisen that I will address in this article.

Some producers are concerned that testing for CL will not distinguish between a goat that has been vaccinated with the CL vaccine and one that is infected with the organism. This is the most specious argument against vaccinating a goat that I've ever heard. (A specious argument initially sounds good but doesn't hold up under analysis.) Vaccines are made from the substance being vaccinated against and they work by stimulating the goat's immune system to mount a response to a modified and usually "killed" version of that bacteria. A "killed" bacteria cannot infect the goat. Of course the goat is going to test "positive" for CL once it has been vaccinated against the bacteria. A good immune system will mount a vigorous attack against the killed organism and produce antibodies. That is how a vaccine works. Responsible producers should want to eradicate a disease via vaccination rather than raising a herd of naive (never vaccinated) goats that might contract the disease if they are exposed to it. We eradicated smallpox and polio in this country by widespread vaccination of the population. That was a good thing. Tests for CL are not 100% accurate; false positives and false negatives are a possibility. Are you as a producer willing to risk the possibility of false positive, false negative, or "borderline" test results just so you can have goats that test "negative" for CL at a single point in time? This is not a responsible way to raise goats. I refuse to sell to people who are that short sighted.

Some goat raisers misinterpret positive serological tests. They incorrectly believe that if a goat is "positive" (possesses antibodies), then it must be a carrier or shedder of the bacteria or is infected or sick with that organism. That isn't true. A positive titer means that the goat's immune system has encountered that organism before, either naturally or by vaccination, and its immune system has either mounted a response against it or it has received passive antibodies from its mother. A "positive" goat may never display clinical signs of CL (abscesses) nor does it have to be contagious to other goats. EXPOSED DOES NOT MEAN INFECTED. I would much rather own a herd of goats that tests positive because they have been vaccinated to resist CL than a herd of susceptible-to-disease goats that test negative. Remember, a negative test means "negative" at a single point in time, i.e. when the blood was drawn and the test completed. Like an inspection on a house you are buying, there is no guarantee that the equipment will be in the same condition beyond that single moment in time when the test was done. On the other hand, vaccination provides some promise of protection against disease. No vaccine is 100%, and the efficiency of the goat's immune system has much to do with how it processes the benefits that the vaccine provides, but a vaccinated goat is much less likely to develop CL than an unvaccinated goat.

With the new CL vaccine from Texas Vet Lab, some swelling at the injection site can be expected. The injection-site "knot" should be firm (not soft). If it is soft, it could be a knot caused by bacteria on the needle or on the surface of the skin and may need to be drained. Do not inject Formalin into these knots. These knots are called vaccine granulomas and arise as a result of the goat's immune response to the vaccine. The adjuvant (vaccine's carrier) and the antigen (active ingredient) are recognized as foreign bodies by the goat's immune system and an inflammatory response occurs at the injection site. They usually resolve themselves over time and that timeframe is often dependent upon the size of the granuloma. If the goat is going to slaughter, the granuloma will come off with the hide. If the goat is breeding stock and you as a producer want it gone, lance and drain and flush with iodine. It is likely a sterile abscess, staph, or arcanobacterium pyogenes. It is not CL.

When administering the Texas Vet Lab vaccine to protect against Caseous Lymphadenitis, use an 18 gauge needle and give the vaccine SQ (under the skin) at the neck because the neck is where the largest number of lymph node sites exist. Give the first injection on one side of the neck and the follow-up booster injection (on never-before-vaccinated goats) on the other side of the neck. Taking the chill of refrigeration off the vaccine by removing the bottle from the refrigerator and leaving it in a climate-controlled environment for a short time increases the syringeability of it. It flows through the syringe more easily and it is less of a shock to the goat's body than the injection of a cold liquid. Vaccinate all non-pregnant and non-lactating goats, including those testing positive for CL and all goats with visible abscesses. Some vaccines are being used "curatively" as well as preventatively; this is one of those vaccines.

USDA labeling does not permit the claim that the vaccine prevents the disease. No vaccine of any kind prevents disease in 100% of the population to which it is targeted. Wording like "aids in the reduction of," "aids in the control of," "aids in the reduction of severity," or "aids in the reduction of infection or shedding" are label requirements. This label wording should not deter you as a responsible producer from using the only CL vaccine available and approved for use with goats.

The dosage for this vaccine is only one cc (1 cc) per goat. The vaccine is labeled to give never-before- vaccinated goats 1 cc and then again in two weeks. The label is based upon the protocol used when testing was done for submission to USDA. I give the initial two injections FOUR WEEKS apart, then annually thereafter. I've verified that it works fine and it causes less reaction by and stress on the goat dosing in this manner. This works for me. As in all situations, use at your own risk. I am not a vet. I am a long-time goat rancher.

Contact Jeffers (1-800-533-3377 or www.jefferslivestock.com) to purchase the vaccine if you live in a state where over-the-counter sales are permitted. If your state requires a vet prescription, then you must buy from your vet. Texas Vet Lab's website www.texasvetlab.com has a page giving a state-by-state listing of how the vaccine is permitted to be sold in each state. The information is available under the goat product link and is titled "CL State Approval List."

Suzanne W. Gasparotto, Onion Creek Ranch, Texas 12/3/15