Female dogs typically get their "period" or go into heat about twice a year, roughly every six months. However, the frequency can vary based on the dog's size, breed, and age. Small dog breeds may have heat cycles more often, up to three or four times a year, while larger breeds like Great Danes may only have one heat cycle per year. The regularity of the cycles can take 18 to 24 months to establish after the first heat. Each heat cycle usually lasts between two to four weeks, with an average duration of about three weeks. During this time, dogs experience physical signs such as a swollen vulva and vaginal discharge. Dogs remain fertile during this time. Dogs begin their first heat usually around six months of age, but this can range from as young as four months in small breeds to up to two years in large breeds. Dogs do not go through menopause like humans and can continue to have heat cycles throughout their lives, though the time between heat cycles may lengthen as they get older. If a dog is spayed, she will no longer go into heat or have cycles. In summary:
- Heat cycles typically occur twice a year (~every 6 months).
- Small breeds: may cycle 3-4 times per year.
- Large breeds: may cycle once per year.
- Each heat lasts around 2-4 weeks.
- Dogs start cycling from 4 months to 2 years, depending on breed and size.
- Cycles continue throughout life unless the dog is spayed.
