Feeding cattle on any grain gets rid of Good fats, and replaces them with bad fats, and shortens your life.
Cows know what they like! Ever see some get into a grain or corn field? They will devastate it eating both the grain heads and they stalks. They also eat wild onions and the grain heads of wild amaranth (pigweed). I always worry about cow manure on a garden as pig weed seeds can pass through unharmed and come up in the garden.