I did a little study of my own. I used only this year's Derby preps, starting with the Risen Star but excluding the Dubai and Turfway races. In order to avoid biasing the results by excluding the horses for whom I don't have TG figures, I guessed at their figures using the figures I do have for the race and my own ground loss estimates.

Of the horses who were off Lasix in the prior race (84), 19% ran new Tops, 41% ran Pairs, 19% ran Off races, and 21% ran an X.

Of horses coming off Lasix (46), 13% ran new Tops, 28% ran Pairs, 22% ran Off races, and 37% ran an X.

Of course, the horses coming off Lasix were probably moving up in class off a strong race and more likely to regress. Three of the horses who ran new tops coming off Lasix were Pletcher trainees (Pioneer of Medina in the Risen Star, Emmanuel in the Fountain of Youth, and Charge it in the Forida Derby).