Heat in female dogs: phases, duration and symptoms
Heat in dogs: estrous cycle, duration, phases, symptoms. We answer your questions and tell you everything about canine reproduction.
Heat in a dog has two phases. The first, in which the ovary prepares to ovulate, is called proestrus and lasts an average of 9 days.
Proestrus is characterized by the dog's vulva, due to the effect of estrogen, increasing in size, swelling, and bleeding. A bloody discharge containing substances called pheromones attracts males.
Pheromones also synchronize the heat of other dogs.
During this phase, males are attracted to the dog, and the dog is playful and inviting, but will reject attempts to mount with growls, moving away, or even snapping. The dog urinates frequently to spread pheromones and attract the attention of males.
At the end of proestrus, vaginal discharge reduces in volume, changes in appearance, becomes less reddish, and becomes more transparent. This indicates the beginning of the true heat period, known as estrus.
Estrus lasts 5 to 9 days in most female dogs. The bitch becomes increasingly receptive, allowing males to mount her.
In most female dogs, during estrus, the vulva reaches its maximum dilation and turgidity. If we press the back of the dog with our hand near the tail, we observe how the bitch moves it to one side, remaining still and exposing her vulva for mounting. She does the same when males mount her, assuming a typical accepting posture.
Optimal time for mounting.
Ovulation occurs during estrus, which is the optimal time for mounting. In most dogs, the days of peak fertility will be between the 11th and 15th day after the onset of bleeding, that is, from the beginning of the cycle. This calculation is valid for the average dog, where the total duration of proestrus and estrus is 18-21 days. In any case, we recommend performing natural matings every 2-3 days, from the time the female accepts the mating until she rejects the male.
However, in some dogs, the periods of proestrus and estrus may be significantly shorter or, on the contrary, longer. In other cases, the period of receptivity may not coincide with the phase of peak fertility.