In a world very much like our own, great race horses of the past have a chance to be reborn as "horse girls"—girls with the ears and tails of horses as well as their speed and endurance. The best of these horse girls go to train at Tokyo's Tracen Academy, hopefully moving on to fame and fortune as both racers and idols. 
Special Week, a high school horse girl from the countryside, has just transferred to Tracen, and she's determined to fulfill her promise to her mother to become the best horse girl in Japan. On her way to school, she takes a pit stop at the race track and instantly falls in love with Silence Suzuka's style, becoming determined to race on the same team as her. 
(Source: Anime News Network)

Junko Hosoe is a horse jockey. Formally belonging to the Japan Racing Association, she currently works as a freelance.

She voices herself as a character in the anime Uma Musume.

The second season of Uma Musume: Pretty Derby.
 
All eyes are on Toukai Teiou as she takes on the Japanese Derby, ready to gallop in Symboli Rudolf's footsteps and become an undefeated Triple Crown Horse Girl. The stands are full. The track is set. It's time to see which horse girl fortune favors! 
 
(Source: Crunchyroll, edited)

The Umamusume are up to their usual hijinks—in teeny-tiny chibi form! Each 3-minute short in this miniseries is packed with silly fun, where you can't help but cheer ALL the racers on! Posted on PakaTube!, the official Umamusume YouTube channel. 

(Source: PakaTube!, edited)