Doberman dalmatian chow start menstrual cycle?

The menstrual cycle, or estrous cycle, in dogs typically begins when they reach sexual maturity, which can vary by breed. For most dogs, this occurs between six months to two years of age. Dobermans, Dalmatians, and Chows generally start their first heat cycle around six to twelve months old. During this cycle, which lasts about three weeks, female dogs may exhibit behavioral changes, swelling of the vulva, and possibly bleeding.