The ability to shoot horses is not easily come by. Unlike racing cars there's also the stride and intent of the horse that varies so much more. The last picture here shows such competition as one horse is trying to fly away and the other is aiming to leap ahead as they race towards us taking that turn.
The panning and shooting is skillful and the blurred b.g. effect provides the impression of of the adrenaline of the race.
Back to the first picture. The bent over left hand rider is trying to get every gm of resistance down to help inch past the other rider. At that point he trusts the horse and they ride as one.
The second and 3rd pictures show a winner or someone trying to catch up. However, we have the same impression of the lone endeavor of rider and steed as one.
Thanks for sharing,
Asher