Symptoms of oral thrush. A symptom is something the patient feels and reports, while a sign is something other people, such as the doctor detect. For example, pain may be a symptom while a rash may be a sign.
Bleeding Stage. The estrus cycle has four stages. The first stage is called proestrus. This lasts approximately 10 days and it is during this stage that your dog will bleed from the vaginal area. This is your dog's preparation for pregnancy phase, but she will not want to mate with a male during this time.
Usually they will have the first cycle around 6 months of age. In my experience as a dog owner, dogs' periods come twice a year and last from a week to a month. During this time, they are extremely horny and beckon for other dogs to hump them, which other dogs often do regardless of gender.