My sweet gelding, Nacho, is 8 years old. Today, I went outside and put on his bosal for a short bareback ride Nothing strange or different. When I mounted, he seemed to be a bit unbalanced but recovered himself quickly. I am only 108 lbs and he is a big boy, but it didn't concern me. We had some fun, I experienced no more problems. Then, when I slid my leg over to dismount, he lost his footing again. This time, he fell to one knee. I was concerned and tried it again with the same result. I finally decided to rub his legs down and give him some more food. I have ordered a mineral supplement with some selenium and am planning to go to tractorsupply later to get some alfalfa and deworming meds. He lost some weight during the winter but not a whole lot, any tips/ideas?