One of the best things about our job is getting to see puppies and kittens grow as we do their vaccine series, so why do we need to do multiple sets of vaccines and what is the correct timing?
Let’s start with the former question. To explain, we need to talk a little about the immune system of young animals.
They start out with very little natural immune system, so all of their antibodies are passed to them from the mother’s milk (called passive immunity). As they grow, their own bodies start to produce their own immunity, or active immunity, as their immune systems mature. Without exposure to vaccinations, however, their bodies don’t know what antibodies to produce unless they come into contact with the actual disease which can be very dangerous. Vaccines allow their immune systems to come into contact with the killed or modified version of the disease gradually, without actually contracting the disease.
*Image by Dari Brown, Ph.D. Senior Director, Livestock
Age of the Animal
So why multiple sets of vaccines then, why not just one at the end whenever their active immunity is more mature?
The truth is we don’t know exactly when the passive immunity ends and the active immunity takes over. This is just an estimated time frame of when it most likely occurs. So as the animal grows we want to make sure they have some protection from disease and to make up for any gaps in the mother’s antibodies.
Vaccine sets are generally 3-4 weeks apart (starting when they are 6-8 weeks old) so that the body gets exposure to the disease and has enough time to mount a response. The more they are exposed, the more antibodies are produced, which means the body can have a faster and more effective response when exposed to the actual disease causing organisms.
Image provided is from the following article: https://www.purinamills.com/swine-feed/education/detail/why-do-weaned-pigs-get-sick-easily