How can you tell when your dog is going into heat?

Answer:
Generally, the first sign is the vulva (outer genitalia) begins to swell, when they are in heat, they will drip blood. Some dogs are clean, and you'll never see a drop of blood, others are not so aware, and you'll have to follow them around the house with a rag.

A heat cycle is not a menstrual cycle, in fact, it's the opposite, and during heat, the dog is fertile and will become receptive to males at the peak of fertility. As soon as you notice signs of heat, you should immediately separate your female from any unneutered males, and ensure your dog is kept secure on a leash or in a safe room while unattended by you.
First answer by Kwinnypoo. Last edit by Kwinnypoo. Contributor trust: 3 [recommend contributor recommended]. Question popularity: 3 [recommend question].