The horse is a gelding...
Look at the following video and for a good bit of it Mine That Bird is in last place and out of the picture. However at about the the 1/4 pole watch the top picture and you’ll see a horse with the jockey in black/silver begin to move along the rail. That is the winner.
http://sports.espn.go.com/sports/horse/triplecrown09/news/story?id=4128767
Here is another video that maybe better.........
http://www.inentertainment.co.uk/20090503/kentucky-derby-2009-video-reply/