Good agencies and breeders keep sound records of their kittens, and will be able to provide at least a close guess. If they did not witness the birth firsthand, the best they can provide is an estimate. Even if a shelter receives a kitten well after its birth, they have an experienced staff and veterinarians who can provide professional estimates. When you take your kitten for its first veterinary exam, ask the vet for his or her educated estimate of its age. During this same visit, your veterinarian will also advise you on the tests and vaccines your kitten will need to lead a healthy life.

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Write a summary of the previous text in Chinese:
问问让你领养小猫的组织或猫咪的前主人。 询问兽医。