Dogs’ menstrual period usually lasts for about 15 to 20 days. The specific time depends on the dog’s physical condition. Dogs generally have their periods twice a year, and large dogs usually have their periods once a year or three times every two years, in the spring. They are in heat from March to May and from September to November in autumn.
Tips:
Dogs will bleed from their vagina during menstruation, so it is best to wear menstrual pants for your dog. It is hygienic and can prevent dogs from being harassed by male dogs.