Brown Discharge from dogs nipples

I have a 13 yr old not spayed female small breed dog, for a week or more now she has had swollen nipples, milk sacs, and is leaking brown and yellow discharge, if you squeeze them gently alot comes out, lately she has had a tiny bit of blood coming for on of her lower nipples and I'm worried, what might this be?

[Aleda M Cheng, D.V.M., C.V.A]

This is not normal and she should be seen by a vet immediately.

She could have mastitis, which is an infection of the mammary glands and can be resolved with antibiotics, infusions and other procedures, or she could have breast cancer.  Your dog's veterinarian should be able to sort this out.

Either way this is quite serious!