New Zealand targets cow burps to cut global warming

Every time somebody eats a beef burger or drinks a milkshake, it comes at an environmental cost. [iStockphoto]

How do you stop a cow from burping? It might sound like the start of a humorous riddle, but it's the subject of a huge scientific inquiry in New Zealand. And the answer could have profound effects on the health of the planet.

More specifically, the question is how to stop cows, sheep and other farm animals from belching out so much methane, a gas which doesn't last as long as carbon dioxide in the atmosphere but is at least 25 times more potent when it comes to global warming. Because cows can't readily digest the grass they eat, they ferment it first in multiple stomach compartments, or rumen, a process that releases huge amounts of gas.