Here's the dollars and sense on corn fed beef: it's cheaper and faster, resulting in cheaper beef for the consumer and more income for the farmer.
Why we feed grain:
"Many folks within our own industry do not truly understand why we feed grain to feedlot cattle. Many cattlemen believe grain is fed to enhance the flavor of beef. Not true. Grain is fed to decrease the cost of gain. Grain contains much more energy than forages.
As a crude example, feed conversions on grain run about 7.5:1. At a current cost of about $80/ton, the feed cost of gain would be about 30 cents/lb. (this excludes interest, vet expense, etc.). If we fed hay, the conversion would be more on the order of about 20:1. At $60/ton, the cost of gain on paper would be twice as much (about 60 cents/lb.). In reality, it would be even higher than that.
The reason is the cattle on grain would gain roughly 3 lbs./day. The cattle on hay, no more than 1 lb./day. In essence, it would take three times as long, and thus we would have three times as much interest and yardage expense (as well as more exposure for death loss).
This brings us to the fallacy that some people tell us we should 'grass fatten' our cattle. On good quality grass, cattle can gain from 1.25 to 1.75 lbs./day - but only for about five months out of the year (during the growing season). During winter in most areas, those cattle would stand still or even lose weight. Instead of 150 days in the feedlot on a grain diet, grass fattening would take two to three years.
It also means we would have to cut down on the cow herd, to make room for the slaughter cattle that are usually hauled off as calves or yearlings. The bottom line is that if we went to 'grass fattening' we would only be able to produce 30 to 40% as much beef as we do today."
Looks like we'll be sticking to a mixed farming scenario rather than going solely grass-fed.