A female dog typically stays in heat for about 2 to 4 weeks, with the entire estrous (heat) cycle lasting longer when including all phases. The heat cycle is divided into four stages:
- Proestrus: This initial stage lasts about 7 to 10 days (can range from 3 up to 21 days). During proestrus, the vulva swells and there is a bloody vaginal discharge. The female attracts males but is not receptive to mating yet
- Estrus: Known as the actual "heat" or mating phase, estrus lasts roughly 5 to 14 days (average around 9 days, but can vary from 3 to 21 days). Bleeding usually decreases or stops, and the female is receptive to males and fertile. Ovulation occurs during this phase, typically a few days after mating begins
- Diestrus: Lasts about 60 to 90 days (can range from 10 to 140 days). The female is no longer receptive to males, and her body either supports pregnancy or goes into a resting phase. Vulvar swelling and discharge resolve during this time
- Anestrus: The resting phase between cycles, lasting about 4 to 6 months (sometimes longer depending on breed). Hormone levels are low, and the reproductive system prepares for the next cycle
In summary, the time a dog is "in heat" (proestrus + estrus) when she is visibly bleeding and/or fertile typically lasts about 14 to 21 days , but this can vary by individual and breed. The full cycle, including diestrus and anestrus, spans several months, with most dogs experiencing two heat cycles per year, approximately every six months
Key points:
- Heat bleeding lasts about 7 to 10 days on average.
- The fertile period (estrus) averages 9 days but can range from 3 to 21 days.
- Total time "in heat" (proestrus + estrus) is roughly 2 to 4 weeks.
- The full reproductive cycle including rest phases lasts about 4 to 6 months.
- Frequency is usually twice a year.
This knowledge helps in managing your dog's comfort, preventing unwanted pregnancies, and planning for spaying or breeding
