Why do puppies get their rabies shot at 12 weeks?

If state law requires puppies to be vaccinated against rabies at 12 weeks, then that is why they are given the shot. Other states have different age requirements. Personally, I prefer to wait until they are six months old.

When living in a country where there was rabies, mine had rabies shots at 4+ months. For the other shots, as the natural immunity provided by the colostrum the puppies took (her first milk) gives them immunity until, by around 5 weeks when it starts to drop off, external vaccination for the rest of the usual vaccination shots isn't given until around 8 weeks, if not later. If done earlier, it simply won't take and is pointless. Of course, if the litter didn't have mum's first milk, vets will normally given an interim vaccination against Parvo and lepto by around 6 weeks.

Provided a puppy isn't exposed to rabies until the first shot can be given at around 4 months, there's no reason to vaccinate against rabies any earlier.

Because until that age their systems are to weak to be able to cope with a rabies shot

So far, you are failing miserably on the student vet front. Puppies DON'T get rabies at 12 weeks; unless there is a HUGE OUTBREAK of RABIES in the local community. Normally, puppies DO. NOT. get a Rabies VACCINE UNTIL.... 16 weeks, PERIOD.

It should be GIVEN (by itself) without ANY OTHER vaccines at that visit (due to the HIGHER likelihood of a vaccine reaction). AND, unlike all OTHER vaccines (that are a measured dose to the WEIGHT of the puppy) the rabies is the SAME dose, whether the puppy is a Chihuahua or a Great Dane. Therefore, you certainly DO SEE a lot more reactions, esp in small or toy breeds. You can GOOGLE that FMI, btw.

I have always heard that they are under their mothers immunity for the first 6 months of their lives. & get their own shot at 6 months. City folks are not likely to run into any rabid animal to bite a puppy to give it rabies. I don't know the logic unless it is to get more money out of you, again & again & again.....new age Vets are greedy.

I would much rather see an old timer Vet than any of these new Vet graduates. They are so greedy. MONEY, MONEY, MONEY

They need their immune system to be advanced enough to actually use the vaccine. Prior to that their mom's antibodies are protecting them. Until their own immune system starts to kick in they would not be able to have any vaccines actually work in them. The timing is done right when one phases out (their mom's) and their own phases in.

Dogs are quick, with cats it takes longer.

Good question though.

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To get around this, we vaccinate puppies in a series - giving a "Distemper-Parvo" vaccine every 3-4 weeks starting around 8 weeks of age until the puppy reaches 16 weeks of age. By age 16 weeks, we can be assured that maternal antibodies have waned and that vaccinations will be effective.

The Puppy Immune System - Why So Many Vaccines?

www.ridgewoodvet.com/services/.../the-puppy-immune-system-why-so-many-vaccines

Very few get them that young, depends on the area and the individual practice, average is between 4-6 months, Research it when you begin your studies, and Good Luck.

So that their immune system is mature enough to develop a response to the vaccine