How Long Does Heat Last?
If your dogs in heat, how long will it last?
The heat period varies from 8 to 30 days with an average of about 20 days. Most female dogs will allow breeding around 10 to 16 days after start of the cycle.
You should consider your pet to be “in heat” for 21 days: 7 days coming into heat, 7 days in heat, 7 days going out. Though conception is most likely during the middle 7 days. If you want to ensure that your dog will not become pregnant, you should keep her confined for the entire 3 week period. Again, not all dogs follow with the norm. Watch your female and record her cycle. It will usually stay the same throughout her lifetime.