I've never posted on here, but your Dusty sounds just like my Dancer started out. She HAS been diagnosed as IR, but my vet was very resistant to admitting it until I insisted she be tested. If you check out the Yahoo website for IR/Cushings horses, there is soooo much useful info on there on how to help your mini. The site is moderated by a vet as well as volunteers, so you can see what other people are dealing with. It has been invaluable to me in my efforts to get my mini back to optimum health. Good luck!