N o other biosecurity tool for protecting the health of the herd is better recognized than the use of vaccines. While vaccine usage is familiar to most dairy producers, the when, what, how, and why of vaccines and vaccination programs is inconsistent and often confusing at best. Since the use of vaccines constitutes part of the critical foundation for our herd health program, we need to understand what we can and cannot expect from vaccines and how to best utilize this biosecurity management tool. Vaccinations accomplish this by tricking the immune system into thinking that a real infection has occurred. Vaccines should serve as a guide or 'blueprint' so the immune system can build protection and raise resistance.
Bacterial infections create illnesses primarily by producing toxins or poisons.
Viruses, on the other hand, create illness by destroying the cells in the body that they have invaded. Bacteria are complete living cells which usually live outside the body's own cells and reproduce by enlarging and them splitting in half. Viruses are extremely small particles which reside inside the cells of the body. Viruses cannot reproduce by themselves, but rather invade the 'mind' of a cell and reprogram it in such a way that the virus infected cell now is a slave to the virus. It then begins to create millions of new virus particles which will be used to infect other cells of the body.