What would happen if you tried to raise or treat a bull like a horse?

Hmmm

When I was a teenager in junior high school, I worked part-time at a large animal breeding center in our rural town, where myself and 5 other girls my age assisted the Resident Veterinarian who was a young woman in her early 20's.

We learned many things about horses and bulls from her, the main things being that they are built very differently from each other and secondly, that horses are far more intelligent than bulls. Horses can be trained whereas bulls are untrainable.

You would be riding a bull.