Is there somewhere to study horse bloodlines?

I have been riding cow horses now for a few years. And i look around at all the good horseman and they always know so much about the bloodlines. I was wondering of there is any way to find out what bloodlines are amazing and if there are any problems with bloodlines. Like if you cross one horse with another is it a bad cross. If one cow horse had a short back or was just plain too small. Like is there a AQHA stud book or what? I would like to be able to learn about the bloodline good and bad. Any suggestions?