LOVELOCK - During the fall, many ranchers are in the process of rounding up their calves for branding and processing. The main management objectives during the fall roundup are: (1) to identify for ownership, (2) to tag for performance, (3) to process for better marketing, and (4) to immunize against disease.
In this article I would like to concentrate on objective number four, the immunization against disease. Vaccination programs should be designed around the production system of each operation based on animal production programs, animal use, and disease history or problem. Two basic types of vaccines are available for use: (1) killed or inactivated vaccines and (2) modified live or attenuated vaccines. Vaccination programs are an integral part of a comprehensive herd health program!
Killed or inactivated vaccines contain the appropriate amount of antigen or foreign protein (called antigenic mass) in the inoculating dose to stimulate the immune system. However, these vaccines usually require two vaccinations over 2 to 4 weeks to fully stimulate the immune system and the memory response.
The immunogenicity of modern vaccines may be enhanced by the presence of chemical additives called adjuvants. Adjuvants are non-specific enhancers of recognition and processing of antigens and are commonly used in killed vaccines. Unfortunately, adjuvants may also increase the incidence of adverse vaccine reactions especially with repeated vaccinations. Some killed vaccines can now immunize with one injection.
Live vaccines produce the antigenic mass by multiplying within the recipient. Living organisms stimulate both humoral (antibodies found in body fluids or serum) and CMI (cell mediated immunity -is an immune response that does not involve antibodies but rather involves the activation of phagocytes, natural killer cells (NK) and the release of various cytokines in response to an antigen). Live vaccine immune responses generally stimulate a higher level of immunity because they produce more antigen(s) through the replication/multiplication process. Immunization with living organism vaccines can be blocked by the presence of preformed antibodies such as colostral antibodies,
(These are the antibodies that are in the milk produced by the cow at birth that is rich in antibodies and minerals, and precedes the production of true milk).
The immune system (both natural resistance and acquired immunity) requires the animal to be in an adequate nutritional state so all cellular and molecular functions are capable of recognizing and responding to limit the invading antigen (agent). Stress has a major depressant factor on the immune response by the release of glucocorticoids that inhibit the molecular and cellular functions.
Nutritional, physical, and mental stresses have an adverse effect on the animal's ability to respond immunologically. Management of stress from environmental conditions and rough or improper handling and inadequate nutrition are significant influences in maximizing the immune response of cattle. In some areas a heavy parasite load may interfere with the immune response.
No matter the vaccination program in use, producers should always: FOLLOW ALL LABEL GUIDELINES AND FOLLOW ALL QUALITY ASSURANCE GUIDELINES.
The following are some guidelines for vaccine care and handling:
• Read the package insert and follow directions for the specific product used.
• If two doses are directed - give two doses, or there may be very little immunity.
• Calves vaccinated when less than 6 months should usually be vaccinated again after 6 months of age.
• To obtain a benefit in the colostrum from vaccination, give the last prescribed dose of the vaccine at least 4 weeks pre-calving.
• Refrigerate and store vaccines as directed on the label. Use an ice cooler to protect vaccines while they are away from the refrigerator.
• Reconstitute only the amount of vaccine which can be used within an hour and then mix more later, as needed.
• Keep the reconstituted vaccine out of direct sunlight and away from excessive heat.
• Remember that some vaccines may cause abortion (IBR) and fetal defects (BVD). Read the label of the specific vaccine for precautions about use in or around pregnant animals.
• Always read the label and be sure the product is suitable for the animals to be vaccinated.
If you are unsure, talk to your veterinarian or call the company directly, before you use the product.
Vaccines are an important tool to use in herd health programs for the protection of animal health. However, vaccines do not prevent all disease by themselves, and should be used in conjunction with good management practices. The timing of vaccination and selection of product are important considerations. It is best to use vaccines as part of a total herd health program. Your veterinarian, who understands the local and current conditions, is an important advisor for any health program or vaccination schedule you plan to implement.
Reference: Vaccination and Immunization: Vaccination Programs for Cattle Operations
James J. England, Caine Veterinary Teaching Center, Caldwell, Idaho, Roger Ellis, Colorado State University, Fort Collins, Peder Cuneo, University of Arizona, Tucson
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