How long does a dogs heat cycle last for?

And how long will she bleed?

2-6 weeks with most dogs but it depends on how old she is.

Heat last for 21 days! One week going into heat Blood showing, one week into heat less blood then one week going out! some dogs bleed more than others too. Make sure you keep her away from all male dogs during her complete cycle! She can get pregnant any time during her 2nd week on!

Your female's season will last for a total of 28 days. Each female is different in terms of how long and how much they will bleed. on average the feemale will bleed about 1 week. I have also had females bleed different amounts on different seasons. Some females bleed almost to the end. . If you are not planning on showing or breeding your girl you should consider spaying her after her season. A discussion with your vet on this topic would be a good idea. There are many health benefits to spaying and it also avoids any unplanned puppies.here is a great website http://www.dogbreedinfo.com/breedingheat.htm

I female is in heat for 21 days. She bleeds from day 1 to about 9. When she is ready to mate at about 10-14 days. I would keep her away from males for another week after that to be safe.