if you are not wanting to bred from her, your better off getting her spayed, the vets right a ***** that is not spayed has a highter chance of developing mammary cancers, and ovarian cancer, both not nice, the other problem they can get is what we call a pyometra which means a uterus infection, makes them very sick and can sometimes kill them, 99.9% of cases with pyometra to cure it need to be spayed anyway. Im not trying to scare you, just let you know the facts, I see older bitches come in to our clinic which all these problems all the time. Bottom line get them spayed at 6 months old before any problems come up. One other thing it doesnt make any difference to the dog whether or not they have a litter of pups or not. It doesnt change their personality or quieten them down like some people think.