Over the years we have found one of the most cost-effective methods of keeping them stabled cleanly and safely is to use good quality rubber matting with a moderate layer of shavings, and to apply Ultra Dri on a regular basis to kill bacteria and ammonia. Obviously, if a horse is injured, more bedding may be required, but Ultra Dri can still be used to prevent the spread of bacteria.  It can, of course, be used on straw bedding, too.