Someone recently asked me why we give puppy and kitten shots the way that we do. “What’s the point in giving them shots every 3 weeks?”
Just like humans, puppies receive some conferred immunity to illnesses through the colostrum. Colostrum is produced in the mammaries in the late stages of pregnancy and the first few days after birth. There are many functions of this “first milk,” including establishing the microbiota or beneficial bacteria in the puppy or kitten’s gut and conferring antibodies to specific pathogens and to infectious disease generally. The colostrum also includes large numbers of leukocytes.
As a result, by nursing within the first few hours after birth, puppies and kitties receive both some specific disease immunities and some generalized assistance to their immune systems. The amount of time a puppy or kitten is protected by conferred immunity from their mother varies from litter to litter, and if we vaccinate your puppy or kitty while it is still protected by this conferred immunity the vaccine will not protect them. So, to be sure that a puppy is fully vaccinated we can either wait until we are certain, statistically, that all puppies no longer have conferred immunity or we can give multiple vaccinations.
There are certain diseases that are endemic to our environment in North Texas and which are particularly dangerous to young animals. Examples are distemper and parvo in puppies and calici virus and panleukopenia in kittens. These diseases are such a serious threat to a young animal’s health that we want to minimize any possible window of lapsed immunity. If we are vaccinating every three weeks, we know that the maximum amount of time an animal can have lapsed immunity is 1-2 weeks.This is also why we advise that you wait until a puppy is 3-6 months old before taking her to the dog park, enrolling in obedience classes, or engaging in other activities that expose your puppy to other dogs and disease carriers.
Proper vaccination protocols on puppies from shelter and rescue environments are particularly important. It is impossible to know the vaccination and disease history for shelter animals prior to intake, and shelter and rescue animals are housed in close quarters. This makes the transmission of infectious disease very common. If you have adopted a puppy or kitten from a shelter environment, please take advantage of the free wellness exams that are often complementary with an adopted pet and follow the veterinarian’s instructions for follow up care, including any additional series of vaccinations still needed or courses of antibiotics or parasitides. You and your pet will both be much happier and healthier!