Trying to grass finish younger cattle up our way is tough but dry heifers as twos fatten pretty easy and eat nice. A neighbor and I did a government test deal where we ultasounded some yearlings off grass then got them slaughtered and graded. Marbling wasn't a part of our grading system back then but they all had adequate fat thickness and colour to grade under the old system. Most grass cattle get marketed now just when they're going to start gaining well-late August/Sept can put some nice gains on cattle.