A female Siberian Husky will enter her first heat cycle between the ages of 6 and 12 months. Each heat cycle can last from 18 to 28 days.
It takes awhile for the heat cycle of a female dog to become regular. An owner can determine if the dog is in heat by the dog's behavior and by the appearance of the vulva, which will become swollen during her cycle.
A dog in heat may urinate more frequently and may become more restless. A blood-stained discharge from the vulva is common, and the female will often become more receptive to the attention of male dogs.
Due to the increased blood flow during a heat cycle, spaying during this time is not recommended. Many vets prefer to spay a female 4 to 6 weeks after the end of the heat cycle.