Female dogs typically go into heat about twice a year, roughly every six months
. However, this can vary depending on the dog's breed, size, and age. Small breed dogs may cycle up to three times a year, while giant breeds might only cycle once a year
. The first heat usually occurs between 6 to 24 months of age, with smaller dogs tending to have their first heat earlier (around 6 months) and larger dogs later (up to 18-24 months)
. Each heat cycle lasts approximately 2 to 4 weeks (14–21 days), with the fertile period (estrus) averaging about 9 days but can range from 3 to 21 days
. The cycle includes three phases: proestrus (beginning with swelling and discharge), estrus (when mating is possible), and anestrus (a resting phase lasting several months)
. As dogs age, their heat cycles may become less frequent but they remain capable of becoming pregnant throughout their lives
. Spaying a dog will prevent heat cycles altogether
. In summary:
- Frequency: About twice a year (every 6 months), but can range from once to three times annually depending on breed and size.
- Duration: Each heat lasts about 2-4 weeks.
- First heat: Typically between 6 and 24 months old, earlier in small breeds, later in large breeds.
This information helps dog owners anticipate and manage their pets' reproductive cycles effectively.
