Cows are endowed with the ability to convert grasses, which humans can't digest, into food that we can digest. They do this because they are ruminants. They possess a rumen, a 45-50 gallon fermentation tank in which specialized bacteria convert cellulose into protein and fats.

Today's industrialized feedlots are producing beef that is consistently bland and of poorer quality than cattle raised on grasses, clover, and alfalfa

Michael Pollan wrote recently in the New York Times about what happens to cows when they are forced into industrial feedlots:

"Perhaps the most serious thing that can go wrong with a ruminant on corn is feedlot bloat. The rumen is always producing copious amounts of gas, which is normally expelled by belching during rumination. But when the diet contains too much starch and too little roughage, rumination all but stops, and a layer of foamy slime that can trap gas forms in the rumen. The rumen inflates like a balloon, pressing against the animal's lungs. Unless action is promptly taken to relieve the pressure (usually by forcing a hose down the animal's esophagus), the cow suffocates.

A corn diet can also give a cow acidosis. Unlike that in our own highly acidic stomachs, the normal pH of a rumen is neutral. Corn makes it unnaturally acidic, however, causing a kind of bovine heartburn, which in some cases can kill the animal but usually just makes it sick. Acidotic animals go off their feed, pant and salivate excessively, paw at their bellies and eat dirt. The condition can lead to diarrhea, ulcers, bloat, liver disease and a general weakening of the immune system that leaves the animal vulnerable to everything from pneumonia to feedlot polio."

Industrial feedlot beef  would be impossible if it weren't for the routine and continual feeding of large amounts of antibiotics to these animals. This leads  to the development of antibiotic-resistant bacteria. The industrial meat industry's practice of keeping cattle in overcrowded feedlots and feeding them corn is most likely responsible for the heightened prevalence of E. coli 0157:H7 bacteria. When cattle are corn-fed, their intestinal tracts become far more acidic, which promotesthe growth of E. coli bacteria, which can kill people who eat undercooked industrial hamburger meat.

E. coli 0157:H7 has only recently appeared on the scene. First isolated in the 1980s, this pathogen is now found in the intestines of most U.S. feedlot cattle. The practice of feeding corn and other grains to cattle has created the perfect conditions for microbes to come into being that can harm and kill us. As Michael Pollan explains:

"Most of the microbes that reside in the gut of a cow and find their way into our food get killed off by the acids in our stomachs, since they originally adapted to live in a neutral-pH environment. But the digestive tract of the modern feedlot cow is closer in acidity to our own, and in this new, manmade environment acid-resistant strains of E. coli have developed that can survive our stomach acids - and go on to kill us. By acidifying a cow's gut with corn, we have broken down one of our food chain's barriers to infections."

Many of us mistakenly believe that "corn-fed" beef is better beef, but it actually isn't. A corn-fed cow certainly does develop well-marbled flesh, but this is simply excess saturated fat that can't be easily removed. Grass-fed meat, on the other hand, is lower in overall fat and in saturated fat. A sirloin steak from a grain-fed feedlot steer has more than double the total fat of a similar cut from a grass-fed steer.  Not only is grass-fed beef lower in overall fat and saturated fat, but it has the added advantage of providing more omega-3 fatty acids. These healthy fats are most plentiful in flaxseeds and fish, and are also found in walnuts, soybeans and in meat from animals that have grazed on omega-3 rich grass and plants. In addition to being higher in healthy omega-3s, meat from pastured cattle is also up to four times higher in vitamin E than meat from feedlot cattle, and much higher in conjugated linoleic acid (CLA), a nutrient often associated with reduced cancer risk.

There are significant environmental benefits to grass-fed beef. According to David Pimentel, a Cornell ecologist who specializes in agriculture and energy, the corn that is fed to industrial feedlot cattle accounts a massive amount of fossil fuel energy consumption. Growing the corn used to feed livestock in the United States takes vast quantities of synthetic chemical fertilizer, which in turn takes vast quantities of oil. Because of this dependence on petroleum, Pimentel says, a typical steer will consume 284 gallons of oil in his short lifetime. In addition to consuming less energy, grass-fed beef has another environmental advantage; it is far less polluting. Pastured cattle's waste simply drops onto the land, becoming nutrients for the next cycle of crops. In feedlots and other forms of factory farming, the animal wastes build up in enormous quantities, becoming a significant source of water and air pollution.

Pasture-fed beef is also far more humane than beef from industrialized operations - the animals are not forced to live in close confinement. The cruelties of modern factory farming are so severe that you don't have to be a vegetarian or an animal rights activist to find the conditions to be intolerable, and a violation of the human-animal bond. Pastured livestock are not forced to endure the miseries of factory farming. They are not cooped up in cages barely larger than their own bodies, or packed together like sardines for months on end standing knee deep in their own manure.