Uma Musume closely mirrors the IRL careers of Japanese race horses that (so far) have raced between 1987 and 2019. Starting with Oguri Cap from Uma Musume: Cinderella Gray and ending with Cheval Grand from Uma Musume: Pretty Derby Season 3.
Small background: Horses are allowed to race when they are in their 3rd year and typically have 3-4 year careers. Then they live peacefully on their farms eating unlimited carrots with the prize money they earned.