Sex

Generally speaking, a dog's first heat cycle begins around the age of six months of age, however, it may begin as early as four months of age in toy and miniature breeds. The first heat cycle in certain gigantic breeds, however, may not occur until they are 18–24 months old.

Due to immature eggs and a lack of physical development, it is highly suggested that young female dogs not be bred during their first and second cycles. Talk to your vet about when the dog is grown enough for breeding if you're thinking about doing so. The average length of a heat cycle is between two and four weeks.

Some female canines may stay receptive throughout the whole cycle, while others may be infertile during the first part of the cycle. When the dog's vulva shrinks back to its usual size and there is no longer any bleeding or discharge, the cycle is ended.

A dog's most fertile time during her heat cycle is a brief nine to ten-day period that starts around 10 days into her cycle and lasts for about five days. However, conception is still possible until the cycle is complete.

The bleeding phase of a dog's heat cycle may last anywhere from two weeks to four weeks, while the whole heat cycle lasts anywhere from five months to seven months. Each of the four stages of the heat cycle is accompanied by its own unique set of signs and behaviours.

Two of these four stages include bleeding or bloody discharge. Dogs have an innate understanding of how to deal with each other throughout their heat cycles, although humans may be needed to prevent discharge from soiling furniture or treat uterine infections.