How can I recognize when my female dog shows signs of being in heat?
You can note that her vulva dilates. This is the first phase, known at the beginning of heat, and lasts between six and nine days. She'll be attracted by males, but will probably refuse any intent of mating. This phase can last between four and thirteen days, with nine days as average. It's not strange if it lasts around 27 days. Don't be surprised if your female dog urinates with greater frequency during this period, it's normal.
Symptom of Female Dog in Heat
As this phase goes on, some blood will arise from the vulva. She will usually lick this zone, and on herthere will be some blood spots. Probably, her appetite will decrease, and she could be more excited than normal. At the beginning of the estro period, when mating takes place, blood from the vagina will disappear. This period can last 21 days, but usually lasts the same as the proestro. Therefore, in heat period is considered to last around three weeks. Real ovulation, liberation of one or more ovules from the ovaries, usually takes place at the beginning of the estro period, in 72 hours. The chemical substances produced by the female dog, used to attract males, are gradually reduced during the estro phase, and then if mating is not possible, the reproduction phase will develop normally until her next period. The anestro phase is larger and the vulva reduces in size. After five months, the female dog will again enter the proestro phase of her reproductive cycle, producing more pheromones, an odor that sexually attracts males.