Cattle ranchers know that marbling depends almost entirely on diet. Cows are ruminants, which means they normally eat grass and do not develop marbling. The result is a more flavorful but less tender steak. However, a grain-heavy diet increases the growth rate as well as the marbling. For this reason, many grass-fed cows are “finished” with a period of corn feeding to develop the desired fatty muscle, or marbling.
