This is again a "wishlist" idea. There was a kind of era for online horse simulation games in the 2000s, which I played avidly being a horse person suffering withdrawals since moving into the city. The vast majority of them are dead and gone now, leaving a bit of a vacuum for those interested in equine-related games who are older than 12. ("Under 15" seeming to be the main target audience for current horse-themed games.) The make-shift solution for the 9000+ plus members of Equus-Sims was to found a modding community for The Sims 3 (by EA) which essentially ran wild with the Pets expansion pack, ripping the game apart and restuffing its innards with horse-related custom content. With more sophisticated competitions and roleplaying then taking place on the forum.

It was all well and good but didn't quite reach the itch I still have; for a 3D horse-orientated sandbox game that is engaging, educational and challenging to anyone, even adults who are well versed in horse husbandry. The Sims, essentially, but intended as a horse game and taking the horse care seriously; none of this leaving your horse's saddle on overnight stuff!

You start off as a stable hand (choosing to work at a racing stable, a sport horse stable or a stock horse ranch) and only by completing the set tasks and challenges and displaying the correct knowledge can you be promoted through the ranks, selecting one of three career paths: breeder, trainer or rider.
There's no real pressure to move on from a position you're having fun in, but once you have earned enough prestige for yourself (through your horse(s) winning things) the paths begin to converge again as you gradually are given more responsibility until you are able to either manage the whole stable, or leave to found your own. It's at this point that the game will really open up and you are free to do exactly as you like, design your establishment and find your exact niche. The game will offer an online multiplayer option for advanced competing, breeding and selling. I'm not ambitious what

(Picture is actually one of my old competition pictures from the forum; essentially you took an in-game screenshot and embellished it with digital painting... Mine tended towards heavily painted.)