I have a female great dane that is just nine months old. She is my first female dog of any kind, and just went into heat for the first time starting yesterday. I was wondering how long it lasts and how often it happens. I bought her a doggie diaper and absorbent pads which she willingly wears in the house, and whenever I let her out to go potty, I take it off until she comes back in. Is this right too? She only is outside to either be exercised or go potty. Thanks.