Let's dispose of one misconception right away: Cows expel methane from the mouth, not from, ahem... the other end. The average dairy cow belches or exhales between 30 and 130 gallons of methane each day as its forestomachs break down a diet of grasses heavy in tough, cellulosic fibers. With some 1.3 billion cows worldwide, ruminant bad breath accounts for 80 million tons of methane each year -- a gas that is 20 times more effective at trapping heat in the atmosphere than carbon dioxide.

Those alarming numbers have prompted scientists to look for alternative bovine diets that might reduce these levels of methane. Researchers at the University of Wales claim that feed containing garlic could reduce methane by as much as 50 percent. They also suggest that cultivating grasses with high sugar levels, such as white clover and birdsfoot trefoil, would reduce methane production by improving cows' digestive process.

Would a change of diet have a negative effect on the quality of the meat? On the contrary: Improving the efficiency of the cow's digestion would mean that the energy lost with each burp could be redirected toward the creation of protein, amino acids, and fat -- all the signatures of a good steak.