Calf roaching his back

Had a problem this past summer withtwo  steers that roached up in their back/loin. 
One was Angus, the other a cross.  It was quite pronounced on one steer.
The steers were criticized for it atthe show.
At slaughter time they each had 16" plus ribeyes and were relatively lean at 1400+ pounds.  Was told Choice+ and YG 2.

Now I have a Shorthorn Plus(JPJ X Hannibal/Angus) calf that is very expressively muscled and is showing signs of the same issue.
He weighs about 550 and is eating about 10 pounds of corn/oat feed a day.
He is also very lean.    He has a date to be cut very soon.

Any tricks or things I have overlooked?

He is in a good-sized dirt lot with other calves and should have enough room to exercise.

Thanks-

As far as I know, roaching is a structural issue...it's not really something you can change completely. You can manage it a little in how you feed, but all you're doing is having the calf looking as good as he can look and hopefully downplaying the issue a little. At this stage, the best way to manage it is to select against it. They don't get more sound as they get bigger or older...issues usually become more pronounced with time. Be very critical of structural issues during the selection process & you won't have to worry about them as much later on.