The short answer: I'm in the equine import and sales industry (show jumpers). I can net anywhere between $25,000 and $250,000+/year depending on how the chips fall.
The long answer: I won't be giving up much of anything. I own a sport horse farm and we import, compete, and sell show hunters and jumpers (and the occasional dressage horse when we get a youngster who decides jumping isn't an option!). I currently live on the farm but I have a team who will continue to manage operations should I need to go out of state for medical school. Regardless, I will continue to take my income from sales and the rental of a portion of the property - which, thankfully, goes for an absolute premium during the winter circuit - so either way, I'll be able to pay the bills.
I'm really hoping that I get into my state university where I'm pursuing my MPH; it's 21 minutes from my (very rural) farm to the (relatively large) city and it would allow me to continue to compete my horses on a semi-regular basis as one of the three major winter circuits on the east coast is less than 10 minutes from my doorstep. It would also be the only conceivable way I could ride regularly during med school. Any other situation would require me to board a horse or two in full training and anywhere worth training is $1,200/month/horse at the base.
My income varies wildly with my overhead, current stock, and the economy. If I buy right, import on a full pallet (meaning that all the slots on the flight are taken), can deadhead the horse from Miami (if they're coming from South America) or Newburgh, NY (if they're coming from Europe), and the horse arrives on the farm ready to jump the 1.20+ or cruise around the pre-greens in a major national competition with an amateur? I could net as much as 60K or more in one sale. If, on the other hand, I find something that seems to have the *it* factor, pay - say - 15 or 20K Euros more for that special something, import on a half pallet (or import something large, or a particularly difficult stallion, or what have you), have extended quarantine due to a fever or cough, have to pay full-boat for shipping, and then come to find out that the horse needs 3-6 months of flatwork before it can even look at a jump again? I may end up losing money.
There's also an enormous amount of overhead in this industry (farm purchase - I'm VERY lucky to own my place outright - taxes, hay, grain, supplements, shoeing, dentist, vet, chiropractor, masseuse, pro-rider, tractor, truck, and trailer purchase and maintenance, farm vehicle purchase and maintenance, supplies, grooms, farm manager, shippers, entry fees, stall fees at competitions...the list goes on and on and on and on) so my monthly bills can be close to - or even in excess of - 20K in a MONTH. So in order to really make a living doing what I do the way that I do it, I have to move a lot of stock or keep my barn relatively empty. During the "off season" (I'm not in a position to go north during the summer ATM), I try my best to get my farm down to just my two personal show horses. During circuit, I can have as many as 10 horses on the property.
All that being said, I have been riding and competing since I was 2. If I wasn't so dang breakable and I wasn't so attached to the idea of a) going into medicine and b) having some semblance of job security/401K/benefits package/etc., I would stay in this industry indefinitely. I'm very good at what I do. I have (and have sold) some incredibly nice horses. I have a keen eye for talent and a head for business, but I will say that my heart can get in the way sometimes. It can be difficult to see a horse you've brought along from a 3 year old with 30 days to a successful amateur owner hunter winning with it's new owner. But it is also very rewarding.
I know I'm going to miss spending all day in britches with hay in my hair and mud on my boots. I'm definitely going to miss having some of the most quiet, awesome co-workers around (y'know, unless it's mealtime), but I've wanted to go into medicine for as long as I can possibly remember and I know that ultimately I'll be able to have my cake and eat it too