Sex

Puppies usually begin showing signs of sexual maturity between the ages of 6 and 9 months. The female dog is in estrus, sometimes known as "heat," when she is sexually receptive throughout her reproductive cycle. During this time, oestrogen levels rise dramatically before dropping precipitously, triggering the ovaries to release eggs.

While six months is a common age for a dog's first heat, it may be much younger or much later depending on the breed. Depending on the breed, the first heat might occur as early as four months or as late as two years. In most cases, a dog's first or even second heat cycle is too early for her to be bred.

It is recommended to wait until her third heat, which typically occurs between the ages of 18 and 24 months. Genetic testing and advice on whether a dog is suitable for breeding may be obtained from a veterinarian.

There are noticeable changes in behaviour and appearance during estrus. A swelling vulva and blood-tinged discharge are possible symptoms of uterine inflammation in a female dog. She frequently becomes susceptible to male canines, who will typically initiate sexual contact once she seems scared or preoccupied.

This includes "flagging," in which the female dog raises her rear end and flicks her tail in the direction of male canines. A female dog may continue to pursue men and engage in courtship behaviour into the latter half of the cycle.