grain fed usually means corn, because it's the cheapest. but it's also one of the most nutritionally worthless foods there is. it's high in sugar and is used to feed cattle because it fattens them up faster so they can me made into steak faster
for grass fed it means you need a lot more space for the cows to graze and to rotate their grazing areas to allow the grass to grow back
for grass fed it means you need a lot more space for the cows to graze and to rotate their grazing areas to allow the grass to grow back