From a biological point of view, both women and female animals share a common "fate". The cycle with all its hormonal changes ensures that reproduction is possible, but at the same time brings with it some unpleasant side effects and risks. The heat of the bitch is therefore an issue that should be dealt with dog owners necessarily. After all, it is not just about the health of the fur nose, but also about contraception or "family planning".
When a female bitch becomes fluent for the first time in her life, can not be said. There are differences between small and large animals as well as breed-specific peculiarities. In general, however, it can be said that a bitch is usually at the earliest at the earliest with six months and at the latest in the second year of life. Veterinarians also refer to the first heat as oestrarch.
The frequency is divided into three different phases, which run one after the other. The first phase is called "Proöstrus" and is also called Vorbrunst. Here is bloody discharge from the vagina of the animal. It also causes a swelling of the vulva and a thickening of the vaginal mucosa. Even now, males are becoming increasingly aware of the bitch, but a fertility has not yet set.
In the second phase, called estrus, the discharge changes color and becomes much brighter. Also, the swelling of the vulva is slowly returning. Now the bitch is in the so-called "standing heat" and can be covered. In their blood, the hormone progesterone increases, while the estradiol content decreases.
At the end of the heat, there is the fury, known in technical jargon as "Metöstrus". Both the swelling and the discharge are now barely visible. Colorwise, the discharge now tends to yellowish, since there are many neutrophilic granulocytes in it. It is possible that a bitch may still be fertile at the beginning of the metrostrus.