A spay procedure is the removal of both ovaries and the uterus. Done correctly there should not be any ovarian tissue left behind, and ovarian tissue is what dictates estrus cycles. If she was cycling then you would notice, usually, vulvar swelling and a vaginal discharge. This won't occur in all dogs, however, safe to say, most. Fortunately, this is not too common if you have a skilled veterinarian doing the surgery. Tests can be done to
determine if any ovarian tissue was left behind.
If your dog is overweight, then perivulvar skin folds can allow
yeast/bacterial infections to occur with various pigment changes. Likewise chronic bladder conditions can elicit the same type reaction. Do not overlook an allergic cause for this type of behaviour. Given the minimal information, I would investigate all possibilities.
Dr. Van Lienden
Dr. Raymond Van Lienden DVM
The Animal Clinic of Clifton
12702 Chapel Road, Clifton
Virginia, U.S.A. 20124