There is no such thing as “bad light”. There is only light used badly. Sometimes you gotta use what you have — in this case, it was overhead florescent lights in an arena, with a tiny little bit of fill from a distant doorway. Many times photographers assume that it’s not possible to achieve good lighting when the light source is directly overhead; not true, Petunia. You simply have to have your subjects look up toward the light, or in the case of a candid like this one, wait for the subject to do so on their own, and be ready.
This one has a sort of National Velvet-y feel to it that really appeals to me. Fortunately, these horses have gotten used to the massive ka-chunk of my medium format shutter. I prefer to first do no harm. People look better on horses than in a crumpled heap under them.