Vaccination programs have been employed in Western Canadian dairies for a number of years with very good protection against some diseases and quite poor protection against other diseases. This has created considerable confusion with regard to the best protocol. It is important to remember that for most diseases the relationship between the infectious agent and the host is sufficiently complicated that vaccination cannot be expected to provide complete protection. Who will most benefit from vaccination. When will the animal most need the protection that vaccines provide.
Vaccination is the act of administering the vaccine.
Immunization is the animal's response to vaccination and it is immunization that actually protects against disease. In general, humoral immunity is felt to be particularly important in protection against extracellular phases of systemic viral and bacterial infections and in protection against toxin induced diseases. Cell mediated immunity is particulary important in protection from intracellular bacterial pathogens, intracellular phases of viral infections, fungal diseases, and protozoal diseases. Antibody on mucosal surfaces is important in protecting against those bacterial and viral diseases where the organism must attach to epithelial surfaces in order to produce disease. Therefore, the nature of each specific disease determines which type or types of immune response are necessary to provide protective immunity.