MULTI-VALENT VACCINES

Most goat producers have heard of seven-way and eight-way vaccines that provide protection against multiple diseases such as types C&D overeating disease, tetanus, and blackleg. These are known as multi-valent vaccines. They are convenient to use and involve giving fewer injections to the goats. A win-win situation, most people would say -- easier on both the person giving the shots and the animals receiving them. However, easy and effective are sometimes mutually exclusive, and it turns out that there are drawbacks to using multi-valent vaccines.

Vaccines are used to stimulate the immune system to produce antibodies to specific diseases. Most vaccines use a small amount of the killed organism to accomplish this goal. For example, the overeating vaccine C&D toxoid (Colorado Serum's brand: "Essential 3+T") that many of us give to our goats is comprised of the killed organisms type C and type D of Clostridium Perfringens, the two most common of many types of Clostridium Perfringens. Initial dosages and annual boosters are necessary to keep the immune system continuing to produce antibodies to these organisms.

Vaccines are processed by the body's lymph gland system. When a multi-valent vaccine hits the lymph system, it can become overwhelmed, especially in young goats whose immune systems are not yet fully functioning. If this occurs, the lymph system basically says "whoa, too much to handle right now, so I'm dumping tetanus protection first and then maybe some of the other ones." The comprehensive protection that the producer thought he achieved has not been accomplished. This may not occur in all goats, but the producer doesn't know which goats got less than full protection.

Using more than two antigens in one vaccine can result in poor antibody production and is strongly discouraged by some vaccine manufacturers. Use of multi-valent vaccines can result in a low level response to most of the antigens or the response may not reach the level of protection to all of the organisms that the goat needs. The failure of the immune system to respond to vaccines occurs at the lymphocyte level. Lymphocytes are specialized white blood cells that are programmed to recognize and kill the organism against which the goat is being vaccinated. Antigen overload can result in diminished production of the disease-specific lymphocytes needed to fight infection.

The best and most effective way to obtain vaccine protection is to give one vaccine on one side of the body and a second vaccine on the other side of the body. When the CL vaccine for goats is available from Colorado Serum soon, instructions will say to give the first dose on one side of the body and the second dose 30 days later on the other side. Lymph glands are all over the goat's body and this method of giving injections provides greater possibility of successful immunization.

The writer thanks Ed Lehigh of Colorado Serum and Bob Glass of Pan American Vet Laboratory for assistance in explaining the complex mechanisms involved.

The author, Suzanne Gasparotto, hereby grants to local goat publications and club newsletters, permission to reprint articles published on the Onion Creek Ranch website under these conditions: THE ARTICLE MUST BE REPRODUCED IN ITS ENTIRETY AND THE AUTHOR'S NAME, ADDRESS, AND CONTACT INFORMATION MUST BE INCLUDED AT THE BEGINNING OF THE REPRINT. We would appreciate notification from any clubs or publications when the articles are used. (A copy of the newsletter or publication would also be a welcome addition to our growing library of goat related information!)

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