Why do young animals need a series of vaccinations?
Puppies and kittens receive antibodies from their mother through the placenta and after they are born, through the colostrum (the first milk). The age at which puppies and kittens can effectively be immunized is proportional to the amount of antibody protection the young animals received from their mother. Antibodies are small disease-fighting proteins produced by certain types of cells called ‘B cells.’ The proteins are made in response to ‘foreign’ particles such as bacteria or viruses. These antibodies bind with certain proteins (antigens) on foreign particles like bacteria, to help inactivate them. High levels of maternal antibodies present in a puppy’s or kitten’s bloodstream will block the effectiveness of a vaccine. When the maternal antibodies drop to a low enough level in the puppy or kitten, immunization by a commercial vaccine will work. The antibodies from the mother generally circulate in the newborn’s blood for a number of weeks. The complicating factor is that there is a