Is Pasture Grass the Solution to Methane from Cows?

By Amanda Kimble-Evans
Published on October 29, 2010
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PHOTO: ISTOCKPHOTO/BRYAN FOUTCH
Maybe we've had the solution all along to the problem of methane from cows: pasture grass.

Taxing livestock burps and farts? Cows genetically modified to be less gassy? The U.S. government is certainly thinking outside the box to solve the problem of methane from cows and the livestock industry. But what if the solution is already in the box? Some innovative farmers and researchers have discovered the key is omega-3 fatty acids, naturally found in pasture grass.

As ruminants, cattle are designed to consume a variety of grasses found on pastureland. A diet high in grains and fillers — the standard in our industrialized food system — upsets the fermentation process in a cow’s rumen. It appears cheap corn- and soy-based feed and a confined lifestyle have created a bad case of industry indigestion.

Recent research from the University of Dublin has found that adding omega-3s in the form of fish oil to the diet of cattle can reduce methane emissions. “The fish oil affects the methane-producing bacteria in the rumen part of the cow’s gut,” says Lorraine Lillis, one of the researchers at the university.

But, how many cows have you seen eating fish? Instead of supplementing an already improper diet with more unorthodox additives, the better solution to the “emissions” problem may also be the simplest: Eat grass, emit less methane.

Scientists working for Groupe Danone, makers of Dannon yogurt, found that when cattle were on pasture in the spring, they were healthier. When they added omega-3-rich grasses to their feed year-round, the cows not only released less methane, but also produced about 10 percent more milk. Now U.S. dairy producer Stonyfield Farm is piloting a program in Vermont, adjusting grain feed to include alfalfa, flax, and other plants high in omega-3s.

The cows’ methane emissions are calculated by the University of Vermont, which analyzes the chemical composition of their milk through a process called gas chromatography. With the right pasture and a winter feed that simulates pasture, some farmers are seeing an 18-percent reduction in methane emissions. If achieved nationwide, that kind of mitigation could account for almost three-quarters of the goal of reducing greenhouse gas emissions in the dairy industry 25 percent by 2020 (an agreement between the U.S. Department of Agriculture and the Innovation Center for U.S. Dairy). Plus, milk from pastured cows is often several times richer in omega-3s than milk from industrial dairy cattle, according to several studies.

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