Good colors and composition. The diffused lighting works for this. The background is a bit distracting. A shallower depth of field would fix this but would also cause problems with the horse in the background...so I can understand the challenge.
I almost shot this almost exact idea. So obviously I think it's the best idea of the whole challenge ;-)
My plan was to get really close to the nearest horse and use a narrow aperture to pull the background out of focus as it can get quite busy and distracting on carousels. I think yours might have benefitted from the same tactic