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Reducing Cows' Contribution to Global Warming

by Patrick J. Kiger

We can buy all the compact florescent light bulbs and hybrid cars that we can afford, but if we’re going to make a dent in global warming, we need to do something about greenhouse gas emissions from the world’s cattle herds. The link between cow burps — and, to a lesser degree, flatulence — and climate change isn’t a new one; back in the late 1980s, the journal New Scientist reported that bovine emissions pumped as much as 100 million tons of methane, a compound that oxidizes to form carbon dioxide into the atmosphere. But outside of outfitting cows with filters to capture their emissions, what is the world to do?

Fortunately, researchers at Gramina, a joint biotech venture by Australia’s Molecular Plant Breeding Cooperative Research Centre and New Zealand rural services group PGG Wrightson Genomics, may have an answer. They’ve developed a genetically engineered grass that reduces the amount of methane that cows belch after chewing the cud.

Science Daily reports that the grass also has been designed to grow in hotter weather, which could enable the cattle industry not only to reduce its contribution to global warming, but also to maintain herds’ productivity despite the effects of climate change.

Methane is created as a byproduct when microorganisms in cows’ digestive systems break down cellulose from the grass they eat. The majority of the methane is released by burping.

“You don’t actually hear the cows burp, but they are permanently releasing methane,” David Beever, international nutrition director of Richard Keenan UK, told Science Daily.

Gramina is using sense-suppression technology to prevent the expression of the enzyme O-methyl transferase. Suppressing this enzyme makes the grass more digestible, without changing its structural properties.

Gramina has already tested the new grass in the laboratory and is planning field trials.

Methane produced by cattle herds amounts to just over 14 percent of the planetary greenhouse gas emissions attributable to human activities.