All livestock, cattle included, evolved on a diet of green leafy plants (mostly grass). That is God's way. That's because the green plant came before animals. The green plant was the first sustainable life form. Only with it could an animal kingdom exist. Consequently, for all of time animals ate virtually no grain. (Grain is the seed of a land-based annual grass plant.) They either ate green plants and/or they ate other animals that ate green plants and/or other animals. Consequently, the green plant has always been at the bottom of the food chain.
These straightforward facts are very important because nutritional scientists report that many of America's leading health problems are caused by diets top heavy in omega-6 fatty acids versus omega-3 fatty acids. Quantities of Omega-6 fatty acids are very high relative to Omega-3 fatty acids in grain, nuts, some fruits, some vegetables, and all grain-fed animal products. On the other hand, Omega-3 fatty acids are about evenly balanced with Omega-6 fatty acids in green leafy plants (on land and in the sea). Therefore, it can be said that the only reason you hear about the need for Omega-3 fatty acids today is because our nation has a grain-based food system that is deficient in Omega-3 fatty acids and many other important nutrients.
Beginning in the late 1970s dietitians and scientists started making new discoveries about fat. One major discovery was that some fatty acids are essential for human health. Essential nutrients are those our bodies do not make. Some of the most crucial fatty acids for optimizing body function are those found in the membranes (cell walls) of all cells, especially those located at the nerve synapses in the brain.