Female dogs are typically in heat for about 2 to 4 weeks, with the average duration ranging from 14 to 21 days. This period is when the dog is fertile and can become pregnant
. The heat cycle consists of several stages:
- Proestrus: Lasts about 7 to 10 days, characterized by swelling of the vulva and bloody vaginal discharge. During this phase, the female dog usually does not allow mating
- Estrus (heat): This is the phase when the female is receptive to males and can last from 3 to 21 days, averaging around 9 days. This is the time when fertilization is possible
- Anestrus: The resting phase between cycles, lasting about 4 to 5 months
Bleeding typically occurs during the proestrus stage and may last about 7 to 10 days, but the dog may not bleed throughout the entire heat period
. In summary, the entire heat cycle lasts approximately 2 to 4 weeks, with the most fertile period occurring around day 10 of the cycle
