During a heat cycle, a dog's vaginal discharge will change color and consistency. It can be:
* Clear and watery: This is the beginning of the cycle.
* Pinkish or reddish: This indicates the dog is in heat and ready to mate.
* Brownish or bloody: This is the end of the heat cycle.
It's important to note that not all dogs will have a noticeable discharge, especially when they are younger.
If you are concerned about your dog's health, it is always best to consult a veterinarian.