Expert: Dr. Louis N. Gotthelf - 9/3/2007

Question
i have two spayed female chihuahuas. 4 and 5 years old. they have recently developed nipples on their chest. is this normal? we did recenlty take in a puppy 8 mos ago.would this be a cause?

Answer
When we spay dogs, we remove the ovaries, which are the major sources of estrogen and progesterone.  But the adrenal glands can also produce these hormones when the ovaries are gone.  In addition, the pituitary gland still produces many sex hormone stimulants.  So if you have a new puppy and the dogs' brains are secreting the hormone Prolactin, mammary development can occur.