Looks like we're headed back to the future. Grass-fed beef is enjoying a renaissance among small-scale ranchers, consumers concerned about their health or the environment, and chefs and foodies who swear by the taste.

"It flies out the door," said Grant DePorter, managing partner at Harry Caray's, which sells grass-fed steaks from celebrated Chicago broadcaster Bill Kurtis' Tallgrass Beef company.

Grass-fed beef still amounts to just a small portion of the U.S. beef market -- 3 percent. But that figure is expected to reach 10 percent over the next decade, the American Grassfed Association estimates. Much of the buzz over grass-fed beef comes from research touting its health benefits. A study last year by the Union of Concerned Scientists found that grass-fed beef was consistently higher in certain omega-3 fatty acids thought to prevent heart disease, and lower in total and saturated fat, than conventional beef.

Cattle raised conventionally may start out eating grass but are kept in crowded feedlots as they mature. They eat corn or grain and are routinely given hormones and antibiotics to grow bigger and fight disease.

The EPA estimates that beef and dairy production facilities in the United States produced about 1.2 million tons of ammonia emissions in 2002 -- about half of total ammonia emissions from animal agriculture.

The law doesn't define grass-fed. But backers are pushing the U.S. Department of Agriculture to rework its proposed definition that requires 99 percent of a grass-fed cow's diet to come from forage but does not address whether the cow is confined or given growth hormones. They want grass-fed to mean a cow has been raised its entire life on pasture, without chemicals and with room to roam.

Source: Chicago Sun-Times