I 100% agree with Mstar, and would never ever get into the horse business. Why would you want to work, instead of have fun riding?
I've been in my career, I'm a graphic designer, for 5 years. I'm really good at it, I love art, etc. I loved the thought of taking something I enjoyed and making it a career. 5 years in..I HATE IT. I've been at a few different business, still can't stand the sight of a computer, graphics, Photoshop...anything that has to do with design. I'm so over work, and I'm only 25...I have another billion years to go before I can retire. Yes, I'm thinking about retirement already.
I currently ride/train and show sale horses..I do get paid when they sell, but I cannot afford to make that my career. I'm happy with that. I like keeping work and horses separate.
I would keep horses as a side job, or hobby. You might resent horses once you make them a career.