dt = switch in distance neg value means back in distance today
positive value means increase in distance today
this is based on today and previous race distance, and value is in furlongs so 1.5 would be increase of 1.5 furlongs in distance today or (6f to 7.5f for example)
rec = recency in days since last race
crun = can run 0 = clean 1 = xform 2 = can't run
can't run is by far the worst, try running it through the data window, is titled cantrun/Xform attribute