Getting a new puppy or kitten is always exciting and most of us just want to cuddle this cute little bundle of fur. It would be lovely if this were enough to keep them healthy and disease free forever but unfortunately it isn't. Just like human children, animal babies also need immunization when they are very young.
A newborn puppy or kitten isn't naturally immune. They do have some antibody protection that they received through the mother's blood via the placenta, but this is roughly only 10%. The other 90% is through the first milk they take in from their mother. This milk is called first milk or colostrum because only the milk produced in the first two days after birth contains antibodies (called maternal antibodies). These antibodies are like little soldiers standing ready to counter any attack from a virus (the enemy). The intestinal lining of the newborn starts changing 6 hours after birth and starts losing the ability to absorb these antibodies. It is therefore very important for new puppies and kittens to start suckling as soon as possible after birth. The newborn is only able to absorb these maternal antibodies for the first two days of its' life. Proper vaccination of the mother will ensure that she has proper antibodies levels which can then be passed on to her babies. If for some reason the puppy or kitten did not receive this precious colostrum (fostered pets, bottle fed pets or perhaps failure of the mother to produce milk), they will be at a greater risk of contracting disease.