How can I tell how old my rescue dog is?

Talk to your vet. Which medical records say what? The Vaccines ones are more likely to be correct.
xox
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If he is only 2 his teeth should be very clean and no plaque on them. If he is 5 there should be a bit of both and he shouldn't be as active a a (almost) puppy - ask your vet!
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Take him to a vet, if they are smart they will know they can tell by the dogs teeth. Sounds like they vet's office maynot know. And its only a rough estimate of the age, not an exact amout. if one says 2-1/2 and the other 5, I would am for around a 3 year old dog or so.
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http://www.seefido.com/html/dog_age__how_to_tell_dog_s_age.htm
http://www.geocities.com/petsburgh/Zoo/1224/canineteeth.html
http://www.pet-tails.com/LPMArticle.asp?ID=224

Hope these help! Go to the vet and ask them to be for sure though.
GOOD LUCK! Thanks for rescueing!
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My first Yorkie was a stray Angel, I took her to a vet right away. He gave an age range 1 1/2 to 2 1/2 years when I found the owners I was told that she was 2 years. Point is a vet can call the age very well even without records. Best of luck to both you and your new fur-baby!
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Usually, if you take your dog to the vet, they can tell how old your dog is by his teeth. It depends on how much tarter/plaque there is. I will say though, as I have been around many stray dogs at the shelter, it can be harder to tell from a stray/rescued dog. Some have bad teeth due to neglect or just bad food.
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A vet will be able to tell you the approximate age of the dog by checking the teeth
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