NEW YORK, NY - AUGUST 15: White House Chief of Staff Gen. John Kelly looks on as US President Donald Trump speaks following a meeting on infrastructure at... Drew Angerer The disconnect between the White Houseâs John Kelly and his boss
While many females will hold to a fairly steady schedule of coming into season about every six months, it can vary. Some girls will only come into heat once year, while others may even come into season every four months. However, these extra seasons are not always fertile.
Starting Heat Cycles. Female dogs go into heat when they are unspayed and reach puberty. The time at which this happens depends on the breed. While the average age at which female dogs go into heat is about 6 months, smaller dogs may enter estrus earlier and larger dogs may not do so until they are nearly 2 years old.