We have mostly Devon or old style, stocky Angus cattle for our grass-fed beef. They are exclusively grass-fed, except for the apples that they love so much. They devour the drops, but sometimes will pick apples right off the trees that dot our pastures.
We rotate them though the fields of grass, and occasionally into areas of brush and trees. They love the shade of the woods on hot days. The system of combining grassland and wooded areas for livestock is called silvopasturing, and is our latest experiment.