The canine estrous cycle, also known as the heat cycle, consists of four stages: proestrus, estrus, diestrus, and anestrus. Here are the details of each stage:

1. Proestrus: This is the first stage of the heat cycle and lasts from 7 to 10 days. During this stage, the vulva swells, and the dog may experience bloody vaginal discharge. The dog is not yet ready to mate, but male dogs may start to gather around her.

2. Estrus: This is the mating period of the heat cycle and lasts from 5 to 10 days. During this stage, the bleeding may reduce or stop, and the dog is ready to mate.

3. Diestrus: This stage lasts for around 60 days. If the dog has not become pregnant, her body will start to prepare for the next heat cycle.

4. Anestrus: This is the resting stage and lasts between 100 to 150 days, making it the longest stage of the full heat cycle. Dogs in anestrus are infertile until this stage ends, at which point the whole heat cycle starts over from the beginning.

It is important to note that the duration of each stage can vary depending on the breed and overall health of the dog. During the heat cycle, dogs may experience physical and behavioral changes, such as swollen vulva, bloody vaginal discharge, increased urination, and changes in personality. It is essential to recognize the signs of each stage to help manage the cycle responsi...