A system that compares, ranks, sorts and grades animals into groups of like kinds according to previously determined predicted maximum values. The system uses a single method such as multi-dimensional single voxel(s) of MR, NMR, MRI, ultrasound, C.A.T. scan, CT scan, P.E.T. scan, or a combination of these, or any equivalent internal measuring device, on a single occasion, to evaluate the animal and determine a number of days the animal must be fed to reach a maximum value. The system also combines internal evaluation with an external animal evaluation system to refine the number of days remaining for the animal to reach a maximum value, and the system, when used in a feedlot, will direct the animal to a feed pen based on the number of days remaining for the animal to reach maximum value.