Description of the Female Dog's Different Estrus Phases

First of all, the word estrus comes from the Latin oestrus which means " a state or period of heightened sexual arousal and activity in mammals"; in what we're concerned, the estrus cycle repeats itself according to an almost identical sequence of anestrus, proestrus, estrus and diestrus. Each one begins when the other one finishes. Because the female dog manifests long periods of anestrus and diestrus, in which sexual activity is practically silent, she is considered monoestrous, whereas under female mammals, for example cows, are considered polyestrous because they have more than one period of estrus per year, without the so called anestrus or rest periods that characterize the sexual cycle of a female dog.

Please read on to have a look at each phase of the complete estrus cycle one by one.