Correct-Topline

The back is firm and level, extending in a straight line from behind the withers to the croup. The back remains horizontal to the ground while the dog is moving or standing. There should be no dip or roach, either standing or moving, as the back must serve to transmit the power generated by the rear quarters for follow through to the forequarters. Rottweilers which display either sloping or high-in-rear toplines are incorrect.

  How that topline should look
  now with a Tail
  For more about Tails see

Incorrect Toplines