Stiff lamb disease. stiff lamb disease. A muscular dystrophy occurring in young lambs fed on ewe's milk or on feed that is deficient in vitamin E or selenium, or both. See: white muscle disease. Please contribute to this project, if you have more information about this term feel free to edit this page. This page was last modified on 3 October 2005, at 21:16.This page has been accessed 2,276 times. What links here | Related changes | Permanent link.