I'm watching some of the japanese (JRA) racing vids of shit going wrong, but a few years old.

Do they not have back-up riders to help catch loose horses?
>To rope them?

No. "catch" is a horse term for doing anything to have a horse come to you or otherwise not run away. Horses are usually herd-bound so you can "catch" them by bringing another horse near them and they'll slow down or come. In general having more calm horses around helps calm down other horses too.

Now I really want to watch a Jap race live to see how they warm up and all that.