persistent estrus

Why Has My Dog Been In Heat For So Long? A prolonged interestrous interval happens when a female had a regular heat but is still not starting her next heat after 16 months or more. Usually, the cause is an ovarian cyst that will start producing progesterone, a hormone similar to androgen, both either stopping

How Long Do Dog Estrous Cycle Last? Similar to the start time, the exact frequency of estrus depends on your dog’s size, breed, and age. Female dogs who have not been spayed go into heat twice a year, around every 6 months. Each heat cycle lasts around 18 days, for generally anywhere from 2 to