Why not keep them up at night late, (watching westerns on TV would keep them interested) then milk them at 8 or 9 after they have slept in a little more?
It's the best time to catch them in REM sleep when they're having erotic dreams...good milk.
Tried that Western video thing. Too many damn stampedes, got 'em all riled up the next day, running all over the place looking for the Duke or Rowdy Yates.