Basic Goat Immunology

We often are faced with many options to help control disease. Adequate nutrition, sanitation, isolation, and treatment of sick animals are often means that help control or minimize disease and should be considered critical to health care management. Some diseases are reduced further by vaccination. In the next few paragraphs we will take a look at the components in the little plastic bottle and how they work to prevent disease.

The Mechanics of a Vaccine

A vaccine is made up of two basic components: one or more antigens and an adjuvant. Antigens are proteins that white blood cells recognize and make antibodies against. This helps the immune system recognize these as foreign and thus allows the immune system to eliminate them from the body. All cells bacteria and virus contain these antigen proteins on the surface of the cell bacteria or virus. To make a vaccine, the manufacturer purifies these proteins and combines them with an adjuvant. The adjuvant stimulates the immune system to develop antibodies to the antigens. The characteristics of these antigens are stored in memory cells which rapidly produce antibodies if that type of antigen is recognized.

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How vaccines work

When the vaccine is injected into a goat the chemicals in the vaccine cause tissue irritation. This results in blood flow to the injection site and with the blood comes white blood cells. The white blood cells become exposed to the antigen and begin a series of processes that cause antibodies to be produced to the antigen. The period of time from when the vaccine is injected until production of antibodies takes 2-3 weeks. At three weeks the level of antibodies is at the peak and begins to decrease. At this time most vaccines require a booster vaccination. If the booster vaccination is given the immune system is again stimulated, and because of immune system memory the result is an antibody level 2-5 times higher than after the first of primary vaccinations. If the booster vaccination is not given, the antibody level declines rapidly. In the world of fighting infection, the more antibodies the more effective the immune system will be at eliminating infection and the more protection the animal has.

The annual booster

Many vaccines require an annual booster. This is to increase the antibody level in the body. Each subsequent vaccination serves as a booster in that it boosts the amount of antibodies present.

Vaccinating Young Kids

Vaccinating young kids is a bit of a guessing game. Kids under 4 weeks of age have a poorly developed immune system and generally don’t respond well to vaccines. There are times when we have no other option but to vaccinate young kids such as in the case of a tetanus or Clostridia enterotoxemia (overeating) problem. Generally kids under 4 weeks of age will receive some protection but not as much as a kid that is vaccinated when it is over four weeks of age.

Side Effects

The most severe side effect that we see with goats vaccines is swelling at the injection site and lethargy for a day or two following vaccination. The swelling is variable between different types of vaccines and is dependent on the adjuvant in the vaccine. Because of this common side effect, we encourage producers to give all injections subcutaneously. Often goats may be off feed, slow, depressed, and lethargic for a day or two following vaccination. They are generally back to normal in 48 hours. As with any animal health product be sure to follow label directions.