This is one of, I don't know, possibly thousands of short films Pete Smith narrated for MGM. For many movie goers of the period, this could have been their introduction to a rodeo (pronounced Roe-Day-O, the "e" in that word is pronounced as in "spinach").
There are many "broncos" who are trying to escape small fenced in areas (gates) and quite a few people today would be offended as animal cruelty.
Smith's humor is pretty dated, although his comments while one rider was getting bucked off of a bronco was fairly humorous. "It's as simple of rolling off a log, from the top of the Chrysler Building", which was briefly the tallest building in the world.
There were also some scenes of "bulldogging" which is where the cowboy tries to wrestle a bull to the ground. Some other scenes of bull riding. It appears that they were using something that would truly be considered animal cruelty - rope tied around the bull's testicles to make the bull buck more violently.