LIV- Module 3- Vaccinations

How do vaccines work

Vaccines expose the animal to parts of pathogens, challenging the immune system to react to a possible pathogen invasion by creating memory cells for the antigens belonging to that specific pathogen. In the future, if the animal is exposed to the same pathogen, the immune system will quickly generate a response before the pathogen can cause disease. Each antibody is usually specific for only one antigen. Because of this, the immune system keeps a supply of millions of different antibodies on hand to be prepared to overcome any foreign invader. For a naïve animal (an animal that never was exposed to the pathogen), it may take 7 to 14 days after exposure to an infectious agent for the body to develop immunity to an antigen, which is plenty of time for some pathogens to wreak havoc on the body. On the other hand, it often takes only 48 hours to mount an immune response to the same antigen in a vaccinated animal.

There are several types of vaccines used in humans and animals. The majority of the licensed veterinary vaccines currently in use are inactivated (killed) vaccines, live-attenuated vaccines, or toxoids. All these represent different strategies used to reduce the risk of illness while retaining the ability to induce a beneficial immune response.

Types of vaccines

  • Attenuated vaccine: Some vaccines contain live, but alterted microorganisms. Many of these are active viruses cultivated under conditions that disable their virulent properties or use closely related but less dangerous organisms to produce a broad immune response. Although most attenuated vaccines are viral, some are bacterial. Attenuated vaccines have some advantages and disadvantages. Attenuated, or live, weakened, vaccines typically provoke more durable immunological responses. But they may not be safe for use in immunocompromised individuals.
  • Inactivated vaccine: Some vaccines contain inactivated but previously virulent microorganisms that have been destroyed with chemicals, heat, or radiation. They are considered an intermediate phase between the inactivated and attenuated vaccines. Examples include IPV (polio vaccine), hepatitis A vaccine, rabies vaccine, and most influenza vaccines.
  • Toxoid vaccine: Toxoids are made from inactivated toxic compounds produced by microorganisms that, when activated, cause damage to cells. Examples of toxoid-based vaccines include tetanus and clostridium. Not all toxoids are for toxins created by microorganisms; for example, Crotalus atrox toxoid is used to vaccinate dogs against rattlesnake bites.
  • Subunit vaccines: These vaccines contain short, specific proteins that are the same as the antigens of the target pathogen. A subunit vaccine uses a component to induce an immune response rather than introducing an inactivated or attenuated microorganism to an immune system.
  • Conjugate vaccine: Certain bacteria have a polysaccharide outer coat, which is a weak antigen.  The immune system has a more robust response by linking these outer coats to proteins (toxins), which are strong antigens.
  • Outer membrane vesicles (OMVs): OMVs are released spontaneously during growth by many groups of bacteria. They have the ability to naturally provoke an immune response in the body of a human or other animal and can be manipulated to produce potent vaccines. The best known OMVs vaccines are those developed for serotype B Meningococcal disease.
  • Heterologous vaccines: These are also known as “Jennerian vaccines“.  The heterologous vaccines contain pathogens from other animals that either do not cause disease or cause mild illness in the organism being treated. The classic example is Jenner’s use of cowpox to protect against smallpox. A current example is using the vaccine made from Mycobacterium bovis to protect against tuberculosis in humans.
  • Viral vector vaccines: This vaccine uses a nonpathogenic virus to insert pathogen genes in the body to produce specific antigens, such as surface proteins, to stimulate an immune response. The new EHDV vaccine uses this technology in combination with the subunit vaccine technology.
  • RNA vaccine: A mRNA vaccine is a novel type of vaccine composed of nucleic acid RNA, packaged within a unique delivery system like lipid nanoparticles. Several COVID-19 vaccines are RNA vaccines and have received emergency use authorization in some countries. 

Vaccination is only one tool to prevent disease and cannot be used as a standalone practice to prevent disease or infection on the farm. Vaccination does not result in immediate immunity or resistance against diseases in all vaccinated animals. It takes time for the animal’s immune system to react to the vaccine. Therefore, if an animal is vaccinated, it does not automatically mean that the animal cannot be infected or develop the disease. The degree of protection is directly dependent on the animal’s health, how well the vaccine is matched to the pathogen, and how well the vaccine is administered to the animal. Vaccines come in many types, but all are delicate organic products that need to be managed and administrated correctly to ensure their effectiveness.

Important factors to consider when using vaccines 

  • Order vaccines from a trusted source. Always order from a trusted veterinary supplier or directly from the company producing the vaccine.
  • Order an adequate amount of vaccine. Always add an extra 10 percent to your order to account for possible vaccine losses during animal handling. If possible, order bottles with fewer doses. Shelf life varies for each type of vaccine. Some vaccines have hours of efficacy after being mixed, some longer. However, it is not recommended to use an open vaccine bottle kept in the refrigerator after long periods. Again, fewer dose bottles help calculate what you need for that day.
  • Correct storage conditions. Check instructions on how the vaccine should be stored. Most animal vaccines require refrigeration at 35 – 45 ˚F (2 – 7 ˚C). Make sure your storage refrigerator works properly, place a thermometer in a prominent place so you can check the temperature often. Refrigerators held in barns or open sheds can have temperature variations throughout the day, affecting the temperature. Never freeze a vaccine, nor let it get too warm. Always avoid direct sunlight on your vaccine.
  • Expiration dates. Always check expiration dates, and always start by using the oldest first. Once opened, always label the bottle with the date, particularly if you will store it for later use.
  • Correct preparation and vaccine shelf life after mixing. Follow directions on the bottle to ensure its effectiveness. This is very important; some vaccines need to be reconstituted with sterile water or have components that need to be mixed. Make sure you follow the instructions and always mix gently. Remember, vaccines are delicate organic products. Prevent temperature shocks. Grabbing a cold vaccine bottle with warm hands can rapidly change the container’s temperature and affect its efficacy.
  • Exposure to UV light. Do not expose vaccines to Ultraviolet light from the sun. Some vaccines can be rapidly deactivated if exposed to UV light.

Below is a list of suggested vaccinations for livestock however the recommendations may vary. Always follow your veterinarians recommendation over any other. 

Infectious diseases threaten dairy cattle health and welfare and can decrease productivity and profitability. Vaccination is an important component of control and prevention of diseases. A vaccination program, however, is not a substitute for good nutrition, adequate ventilation, effective sanitation, and other health management procedures. Vaccines help prevent infectious diseases, but no vaccine provides 100 percent immunity for all animals in a herd. Vaccines raise the general level of herd immunity so that the spread of an infectious disease or severity of clinical illness is minimal.

Vaccination programs should be developed in cooperation with the herd veterinarian. Individual herd circumstances, including disease history, biosecurity, management, housing, and other factors, affect the specific vaccination programs in a dairy operation. Type of vaccine, such as killed or modified live, stage of production, costs, benefits, and other factors must be considered. Rigid recipes that fit all production units are impractical and even dangerous if not instituted in individual herds with professional care. Improper use of vaccines can result in cattle that are not adequately immunized.

Injection sites for livestock vaccines:

  • Subcutaneous vaccination: In front of the shoulder blade
  • Intramuscular: Can be given in the rump, thigh, or neck

Vaccines Cattle:


  • IBR, BVD, PI-3, BRSV
  • Leptospirosis (5 strain)
  • Clostridial group – 7 or 8 way
  • Histophilus somnus (Needs to be risk based-consult with your veterinarian)


  • IBR, BVD, PI-3, BRSV
  • Leptospirosis (5 strain)
  • Clostridial group – 7 or 8 way


  • Clostridial group – 7 or 8 way
  • coli mastitis vaccine at least twice, at six and three weeks prior to calving
  • Rotavirus, coronavirus, and E. coli scours vaccine twice, at six and three weeks prior to calving


Cows are generally vaccinated for IBR, BVD, PI3, and BRSV virus, leptospirosis, clostridial, E. coli mastitis, and calf diarrhea diseases during the lactation period and/or the dry period. Modified live virus vaccines may not be able to be used at this time. Consult with your veterinarian

Small Ruminant Vaccines

  • Clostridium perfringens
  • Clostridium tetani
  • Parainfluenza Type 3
  • Tetanus/Lockjaw
  • Enterotoxemia Type C
  • Contagious Ecthyma/Orf
  • Rabies

Kids and Lambs

CD/T (Clostridium and Tetanus) should be given at 1-3 weeks old and then two booster shots at 4 week intervals. This timing will provide protection when they are disbudded, tail docked, and castrated.

Pregnant Ewes and Does

CD/T should be given 6 weeks prior to delivery and 3 weeks prior to delivery if they are first time moms. If they have birthed before it can be given in the last month of pregnancy.

Breeding Rams and Bucks

CD/T should be given 1 month prior to breeding as more injuries can happen when bucks and rams are in rut.

Companion Goats and Sheep

CD/T Annually

Rabies Annually

Rabies Vaccine

All sheep and goats can be vaccinated for Rabies at 3 months of age and then annually.

Swine Vaccines

  • Swine erysipelas. Erysipelothrix rhusiopathiae causes diamond skin disease in addition to arthritis, heart disease, and abortion
  • Colibacillosis
  • Atrophic rhinitis
  • Leptospirosis
  • Clostridial dysentery
  • Mycoplasmal diseases
  • Porcine pleuropneumonia


3 days: Erysipelas,vPorcine pleuropneumonia

1-2 Weeks: Atrophic rhinitis, Mycoplasmal diseases

3 to 6 weeks (weaning) : Erysipelas, Colibacillosis, Leptospirosis

 10-12 weeks: Erysipelas, Leptospirosis

Gestating Sows 14 to 21 days before farrowing:

Erysipelas, Colibacillosis, Atrophic rhinitis, Clostridial dysentery, Mycoplasmal diseases

Leptospirosis and Porcine pleuropneumonia two to four weeks prior to breeding. 

Breeding Boars


Erysipelas, Colibacillosis, Clostridial dysentery, Mycoplasmal diseases, Leptospirosis, Porcine pleuropneumonia

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