Designing effective calf vaccination programs

Abstract

Vaccination is an important component for the prevention and control of bovine bacterial and viral diseases. Modified-live vaccines (MLV) have been used because of the good antibody response, longer duration of immunity, fewer doses needed per animal, and lower cost. The selective pressure from an animal’s immune response may lead to new viruses that persist and cause problems in the herd. An interesting vaccine will be the live Pasteurella multicida and Mannheimia hemolytica vaccines. Non-adjuvanted MLV vaccines also fail to booster well vaccinated animals as active vaccine-induced immunity neutralizes vaccine virus preventing the MLV from replicating and preventing a booster immune response. Improved adjuvants have increased the scope and duration of inactivated virus immunity. Inactivated vaccines generate cell-mediated response and can enhance the immune response in well-vaccinated animals. This whole process from vaccination to achieving mature immune response takes at least 3 weeks. This fully developed mature primary response can then be boosted to get a true anamnestic secondary response. There is no "single vaccination program” that will work on most farms or ranches. Each vaccine program needs to be designed based on the actual threats and needs of the farm, and not based on a company’s or neighbors suggested program.