I was going to say, if the calf were super young, this is fairly common, but at this age, they should be over it. We've only had this happen with one of our simmi steers and labeled him lazy, we tied him up behind the tractor, walked him, and as soon as he fell, we'd stop, lower the the 3pt, and he'd pop back up. Dont know if this will work in your case but it did for ours. DO NOT DRAG the calf, thinking they will get up because you keep going. Usually these things just take time and patience.