Cows are notoriously gassy creatures. Globally, more than a third of methane generated by human activity comes from livestock farming, a good deal of it in the form of bovine belching (yes, belching — not the other end). This is a serious problem, given that methane is 25 times more powerful than carbon dioxide at trapping heat.
Enter a Danish research team that is testing out one potential solution in the form of an unassuming herb: oregano.
"Oregano has essential oils with a mild antimicrobial called carvacrol, which can kill some of the bacteria in the cow's rumen that produce methane," explains Kai Grevsen, a senior researcher at Aarhus University who specializes in crop science. "Of course, you can't kill all of the bacteria, or the cow would die."
Reining in cow burps is an issue that agricultural scientists have been working on for years, and there are some other promising solutions. For example, a team at Penn State has reported that adding the chemical 3-nitrooxypropanol (3NOP) to cattle feed can reduce methane emissions by 30 percent. Other scientists are experimenting with different additives, feed combinations and even an anti-methane vaccine.
Unfortunately, many of these remedies are problematic (or prohibited) for organic farmers. And — let's face it — the same shoppers likely to consider cow emissions are probably the ones reaching for organic milk. That's why oregano is so intriguing to researchers. One of the sponsors of Grevsen's study, along with the Danish government, is Naturmælk, a Danish organic dairy hoping to make its products more climate-friendly.
This isn't the first study to consider oregano for this purpose — in fact, it builds on earlier work by the lead researcher on the 3NOP study. (Dairy nutrition science is a fairly small world.) But while previous studies on oregano have been short and sweet, the Danish research, which kicked off earlier this year, will run through 2019. And it will include both a technical phase (think cows in little booths with lots of sensors) and a real-world phase on several organic dairy farms.
Grevsen says another major difference is that his team will use "Greek oregano," which has a significantly higher concentration of belch-suppressing essential oil than oregano used in earlier research. They hope this oregano feed could reduce methane emissions by up to 25 percent.
And, if it works, there's (buttercream) icing on the cake:
"A cow loses a lot of energy in releasing all this methane," explains Grevsen. "By blocking the bacteria, the energy that doesn't get lost can be used by the cow to produce more milk."
There is also the question of what this will taste like. Grevsen hasn't tried any oregano-milk — yet — but he assures that those earlier studies found no hints of pizza or spaghetti in the final product. He says there is even some evidence that oregano changes the composition of fatty acids, creating a better-quality milk. Whether that remains true with the "turbo-powered" oregano is yet to be taste-tested.
One criticism of oregano is that, in past studies, it hasn't presented as a particularly economical solution. But the willingness of Danes to spend money on organic dairy — 30 percent of milk sold in Denmark — makes this country an obvious place to keep working on the problem. In fact, a major part of this study is focused on the plant side of things: how to produce the best oregano specimens and use them most strategically.
"We definitely think this could become a widespread solution, for both organic and conventional farmers," Grevsen says. "It just depends on finding an inexpensive way to produce the oregano."
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