A Kemono Friends character. One of many "Friends" in Japari Park. The Thoroughbred Trio were created for a promotion involving the Anime and the Japan Racing Association. They have since integrated with the wider franchise and the JRA moved on with a different franchise.
Horses and Thoroughbreds are better explained in Brown Thoroughbred's page.
A white horse denotes a horse with a white coat (or a coat splotched with white) with pink skin, caused by a dominant white gene, usually created from a random fortuitous mutation. For this reason, white in Thoroughbreds is very rare and few thrive in the racetrack simply due to demographics (for example, only one white horse has ever won a 1st grade race and only as recently as 2020, this one eventually won two more races of that grade). They are not to be confused with gray horses, horses who, born as chestnut or bay, become lighter in color with age, eventually ending up with a white coat and dark skin.
White Thoroughbred is (naturally) a horse girl with long white hair resembling a mane in braids, wearing a white sports ensemble.