Developing Vaccination Programs for Cattle in Virginia

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John F. Currin, DVM, and Tom Bailey, DVM, MS, Extension Veterinarians
and R. Tom Bass, DVM,
all of Production Management Medicine
Virginia-Maryland Regional College of Veterinary Medicine
Virginia Tech

Many farmers vaccinate their cattle against disease. Good vaccination programs serve as the foundation of good herd health programs and prevention many of the "train wrecks" that we have all heard about. Vaccination programs must be individualized for different farms and management systems. Knowledge of the factors involved in developing these programs will help you and your veterinarian develop a better overall herd health plan. This article is the first in a multi-part series on developing vaccination programs on Virginia farms. The basic definitions associated with vaccines and vaccination programs are described.

Vaccination -- Vaccination is the act of giving a vaccine to a cow. Vaccination does not guarantee that a cow will not develop a disease.

Immunization -- Immunization is the reponse of the cows immune system to a vaccine.

Protective Immunity -- The development of an immune response that should prevent an animal from getting a particular disease. This is the goal of all vaccination programs. Protective immunity develops no sooner than 7-14 days after vaccination.

Modified-Live Virus (MLV) Vaccine -- Modified-live virus vaccines contain viruses that have been altered so that they will not cause disease but will still replicate in the cow's body. These vaccines typically stimulate a stronger and longer lasting immunity than killed virus vaccines. In most cases they also do not require a booster to be given. Modified-live virus vaccines are very susceptible to disinfectants and ultraviolet light (sunlight). Care must be taken to ensure that syringes and needles do not contain any disinfectant or soapy residue and that vaccines are not exposed to sunlight for long periods of time. Modified-live virus vaccines must be mixed prior to use and any vaccine left over must be discarded at the end of the day.

Killed Virus Vaccine -- Killed Virus vaccines contain viruses that have been killed or inactivated during production. These vaccines all require a booster to be given 14-28 days after the initial vaccination. This means that previously unvaccinated cattle will not develop an immune response until 21-35 days after the initial vaccine is given.

CC / ML -- CC (cubic centimeter) is the common measurement of volume found on most syringes. Vaccines doses are most commonly listed as ML (milliliter). The two measurements are equal so if the label calls for 2 ml's to be given you should draw up 2 cc's in the syringe.

Bacterin -- A bacterin is a bacterial vaccine that has been inactivated but should still stimulate an immune response. Some bacterins require a booster in 14-28 days while others require only a single dose annually. Blackleg and lepto vaccines are two common types of bacterin vaccines.

Modified-Live Bacteria -- There is currently one modified-live bacteria vaccine on the market, Presponse HM®. This vaccine has been altered so it will replicate in the body for only a short time (18 hours). Care must be taken to ensure that all syringes and needles are free of disinfectants and no antibiotics are being given at the same time as the vaccine. If either of these situations occurs the vaccine may be inactivated and protective immunity will not occur

Toxoid Vaccine -- A toxoid vaccine is made against the toxin an organism produces instead of against the actual organism itself. Modern pasteurella vaccines and tetanus vaccines are two examples of toxoid vaccines.

Maternal Immunity -- Maternal immunity is the protection that a calf acquires from the colostrum it nurses on it's first day of life. This protection is essential to the calf's well-being during the first weeks of life. However, this immunity can interfere with the calf's ability to respond to a vaccine. This interference disappears some time during the first four months of life. Maternal immunity is the reason that vaccine labels recommend a booster if the vaccines are given to calves before four months of age.