Vaccinations, Immunization and Sanitation

We all know about the importance of routine vaccinations/immunizations for the control of infectious diseases and that every goat should be adequately immunized (vaccinated) in your herd. However, do you know how vaccines work to protect your goats? Below is a general explanation of how vaccines work in people, dogs, horses and goats.

The term "vaccine" has come to mean all types of biological agents used to produce active immunity—they stimulate the body's immune system to protect against a specific infection. Vaccinations vary in the amount of immunity they create, based on the number and timing of the immunizations, the dose and the specific characteristics of each vaccine. To understand the protection that vaccinations give, you must first understand some basics about the immune system.

How the Immune System Works

The immune system is the part of the body responsible for fighting off attacks from viruses, bacteria or other infectious agents. The goat's ability to respond to a disease or a vaccine rests principally in the T-cells and B-cells of the lymphoid system. B-cells are responsible for antibody production. T-cells do many things, including stimulating B-cells to produce antibodies.

The immune response involves both functioning B-cells and T-cells. A vaccine works by safely encouraging an immune response that will be effective against a specific disease. The body thinks the vaccine is the disease and creates an antibody to combat the attacker. Antibodies are specialized proteins (immunoglobulins) secreted by mature B-cells in response to an antigen—any substance the body recognizes as foreign. Antibodies are specifically designed to react with the antigen that stimulated their production in the first place.

How the antibodies behave is determined by their physical, chemical and immunological properties. There are five classes of antibodies, each with a different function:

  • IgA (Ig stands for immunoglobulin) is present in external secretions such as tears, saliva, milk and the mucosa of the respiratory system. Its production is stimulated by an antigen coming in contact with it, not by an injectable vaccine or infection circulating throughout the body. However, an intra-nasal vaccine can stimulate the production of the IgA antibody.

  • IgE is the antibody responsible for allergic reactions.

  • IgM is the first antibody formed in response to an antigen. It is first on the scene and doesn't live long. If the body only made IgMs, your protection against an antigen would be short-lived.

  • IgG is late on the scene, but confers long-lasting immunity.

  • IgD has not been proven to have any antibody activity.

When an animal or human is immunized (vaccinated) for the first time in its life, IgM production begins immediately, peaking within a few days (day 4-5) and disappearing, leaving no permanent protection. IgG production starts (day 3) just prior  to the IgM peak level of production. The IgG production increases daily and peaks around 9 to 14 days and then levels off and begins to decrease production around 21 days. This is the level that remains circulating in the system and maintains protection over time.

When an animal is later immunized for a second time with the same or similar antigen (a booster shot), there is a quicker and higher level of IgG antibody production, with the immunity lasting longer than the first time. IgM production may be similar, but IgG formation is far greater than the first time. This is why a series of shots is important—each immunization in a series increases antibody production and gives long-lasting immunity. Don't skip any booster shots but don't over vaccinate either!

A vaccination isn't foolproof. It can be overpowered, resulting in the goat getting the infectious disease despite being vaccinated. This can be caused by massive exposure to bacteria or a virus, contact with a mutated or highly virulent strain, high stress, poor sanitary conditions or a combination of the above factors.

How Sanitation Works with Vaccinations to Protect Your Goat

Good sanitary and animal husbandry techniques are designed to limit exposure to infectious organisms. Vaccinations work together with good sanitary practices to make one comprehensive, effective system of protection. You can't have full protection without both vaccination and sanitation.

Here's an example. The goats at Bozo's farm have pneumonia, which can be caused by either bacteria or  viruses.

Despite warnings from the owner of Bozo's farm, John Doe continually comes to visit for a cup of coffee and chitchat. John Doe returns home and interacts with his healthy goats and their environment.

When John Doe visits next, Bozo's farm owner again warns, "Don't come over, my goats are sick." John Doe brushes off the warning. "It's all right, my goats are vaccinated," he says and continues to return for his daily coffee and gossip session.

Unknown to John Doe is the fact that pneumonia is spread through respiratory secretions. The causative agents spread through the air in tiny droplets every time an infected goat  coughs. Airborne droplet infections saturate everything in the environment where goats have been coughing: feed tubs, water tanks, the ground, clothes and walls, among other things.

On each visit to Bozo's farm, droplets cling to John Doe and he brings more of the agents back to his farm. After a week or so the goats at Bozo's farm have recuperated, but now John Doe's goats are sick.  How did it happen? On every visit, John Doe increased the population of the causative agents on his farm. Finally the goats couldn't tolerate the massive exposure, and the causative agent overpowered any protection given by the vaccine.

The disease spread further when John Doe visited his other goat-owning neighbor as he brought more and more of the agents with him—the cycle starts all over again. 

The biggest factor in transmitting diseases are people. A person touches an infected goat or an object in the environment where the sick goat lives, picking up bacteria and viruses and then interacts with another goat who would not ordinarily have contact with the infected animal. The second goat gets the disease, too. Sometimes we carry disease from farm to farm on our hands, our clothing and, especially, our shoes.

You can take steps to reduce transmission of disease. If you own a farm, make sure visitors and farm help disinfect the soles of their shoes before entering and exiting an infected area. Make a shoe bath by placing a shallow baking pan with a layer of antiseptic or disinfectant solution by the door. Anyone entering or leaving the area should cleanse the soles of their shoes. That way they won't bring anything in or take anything nasty home with them! (Be sure no animal can drink or step in the shoe bath.)

Always wash your hands before and after handling other goats. Hand contact is a major way disease is spread between goats and other animals, including people.

Any goat brought into your farm should be isolated for a couple of weeks and watch for signs of illness.  When it comes to disease, goat shows and sales create special concerns. Goat-to-goat contact is common, and person/goat/goat contact is also common. Because many diseases are spread through the feces, you can decrease the chance of bringing diseases home with a spray disinfectant such as Lysol. Carry a can with you and spray the bottoms of your shoes as you get in or out of your truck, car or van. Carry a small bottle of hand sanitizer and use it often. If your goat has ringworm, which is caused by a fungus, you may inadvertently spread the fungus from one goat to another by using the same grooming tools. The solution is simple: disinfect your grooming equipment.

Passive Immunity

In humans, antibodies are transferred to the fetus through the placenta. In animals, like dogs, horses and goats, this antibody transfer occurs in the first twenty-four hours of life through the colostrum, or premilk from the dam (mother).

Colostrum contains a very high concentration of all the dam's antibodies. These are readily absorbed through the newborn's intestinal tract and protect the kid. This is called passive immunity—immunity that is transferred.

It's important that as much of the passive immunity as possible be transferred. It is absolutely imperative that the newborn be given the dam's colostrum as soon as possible. Without antibodies, the kid is susceptible to every infection present in the environment.  The kid's ability to absorb the antibodies from colostrum diminishes after twenty-four hours. Make sure all kids get colostrum and if the dam has none, then you can use a colostrum replacement. However, the better solution is to milk out a a cup or two of colostrum from each doe and store it in the freezer for those "just in case" problems.   Freeze the colostrum in small containers, i.e., ice trays or small plastic containers.  Colostrum will not keep well in the refrigerator for more than a day.  For those "just in case moments", you will need at a minimum 8 oz per kid of colostrum for the first day.  I also collect and store second day milk from the doe as well, it is a nice transition from 100% colostrum to regular goat milk. 

The maternal antibodies can interfere with the immunization of your kid as late as ten weeks of age. By having a series of immunizations over time, you increase the likelihood the kid is protected.