Newborn animals receive protection from antibodies in their mothers' milk.
To be sure that newborns receive this protection, immunize mothers before breeding. Continue vaccinations at three week intervals until the animal is 12 to 16 weeks old. Veterinarians recommend starting the initial set of vaccinations between 6 and 8 weeks because the younger animals are more susceptible to disease and illness. If the animal is an unvaccinated adult, it can receive the first set of shots with a follow up three weeks later. There are separate core vaccinations recommended for puppies and kittens that combine all the needed vaccinations into one, but a rabies vaccination is important for both.