Signs of a Dog in Heat
A female dog can come into heat as early as 6 months old. The heat period lasts about 3 weeks and occurs usually every 6 months.
If you plan on breeding your dog, it's best to wait until at least her 2nd heat when it will be healthier for her and the puppies.
Here are some signs of heat to look for.
About a month before going into heat, your dog may undergo a personality change, sometimes more affectionate, sometimes standoffish.
Her vulva will swell and will appear larger and colored bright pink.
She will urinate frequently to leave her scent so as to attract males.
There can be changes in her breasts, coloring a deeper pink and slightly enlarged.
When your female begins to bleed, that's the first sign she is in heat. Ovulation is usually about 12 days after the first sign of blood. The color of the blood changes to pale pink or yellow. She may be friendlier towards other dogs.
If you suspect that your dog may be going into heat, you can also have your vet check her progesterone level with a simple blood test.
To prevent your dog from going into heat and mating, producing unwanted puppies, it's best to have her spayed.