[DanaRuns]

Dogs don't go through menopause, so they are fertile into old age. In fact, chemically and hormonally, bitches are "pregnant" almost all the time. This keeps their reproductive system healthy into old age. It's not like humans at all.

I've heard of bitches being bred as old as 8 or 9. I don't know of any increased risks of birth defects due to age. Perhaps others know more than I do. We retire our bitches very young, so I've never had to deal with that. We do three litters, back-to-back-to-back (assuming healing and no complications), and then retire them. That usually means they are retired by age 5, so I've just never investigated that question.