One of my buddies I barrel race with has a 3 or 4-year-old mare that will urinate on herself when she is running. The other day I noticed her peeing when she was just sidepassing. My friend says it's just nerves, and I heard someone else say it could be a busted gut. (???). I've looked it up on google and can't get a clear answer on why this horse could be doing this. Does anybody else have a horse that does this?