After a dog gives birth, her puppies are completely dependent on her for their nutrition. During this period, the pups take all of their meals in the form of milk, which the mother produces naturally and the pups consume by suckling. The period when they transition away from milk and toward solid food is called weaning, and during this period, the mother's teats go back to normal as milk production slows to a halt.
As puppies quickly grow in the weeks after their birth, they can't continue to survive on milk alone. After five or six weeks, the mother's milk production slows down. Your vet can recommend a dietary change to accommodate this process and prevent the mother from producing more milk than her pups need. Her puppies will develop sharper teeth and claws, making nursing uncomfortable for her, and she'll start rejecting their attempts to suckle. During this weaning period, which takes about one week, her teats will go back to normal, as her body gradually will stop producing milk and her puppies will start eating solid food exclusively.
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