why do dogs bleed from their vagina?
Its part of their heat cycle where they slough off the uterine lining and grow a new one ready for placental attachment.
Dogs are usually in heat for about 3 weeks. The first week they have a red discharge, then the second a clear or straw colored discharge, then almost no discharge the last week. You have to keep them away from males the entire heat season.
Dogs go into heat at any time between 6-12 months usually. Usually they come in heat every 6 months after the first heat.
Hope this helps you!