I also saw that on tv. I believe it was "when good pets go bad II"
I couldn't believe it. The poor horses are doing what's natural for them, but I hated how the people there were thoroughly enjoying it. It really disgusted me.
I know!! I've never heard of it before and I was looking for something else on /youtube when I found it. What disgusts me is the way they cheer and carry on. I mean the horses would be going to slaughter but unless they are champion fighters they get killed anyway.