Unusual feed supplement could ease greenhouse gassy cows

August 26, 2010, Pennsylvania State University

(PhysOrg.com) -- Cow belches, a major source of greenhouse gases, could be decreased by an unusual feed supplement developed by a Penn State dairy scientist.

In a series of laboratory experiments and a live animal test, an oregano-based supplement not only decreased emissions in dairy cows by 40 percent, but also improved milk production, according to Alexander Hristov, an associate professor of dairy nutrition.

The natural methane-reduction supplement could lead to a cleaner environment and more productive dairy operations.
"Cattle are actually a major producer of and methane is a significant ," Hristov said. "In fact, worldwide, livestock emits 37 percent of anthropogenic methane."

Anthropegenic methane is methane produced by human activities, such as agriculture.

Compared to carbon dioxide, methane has 23 times the potential to create global warming, Hristov said. The bases the global warming potential of methane on the gas's absorption of , the spectral location of its absorbing wavelengths and the length of time methane remains in the atmosphere.

Methane production is a natural part of the digestive process of cows and other ruminants, such as bison, sheep and goats. When the cow digests food, bacteria in the rumen, the largest of the four-chambered stomach, break the material down intro nutrients in a . Two of the byproducts of this fermentation are carbon dioxide and methane.

"Any cut in the methane emissions would be beneficial," Hristov said.

Experiments revealed another benefit of the gas-reducing supplement. It increased daily milk production by nearly three pounds of milk for each cow during the trials. The researcher anticipated the higher milk productivity from the herd.

"Since methane production is an energy loss for the animal, this isn't really a surprise," Hristov said. "If you decrease energy loss, the cows can use that energy for other processes, such as making milk."

Hristov said that finding a natural solution for methane reduction in cattle has taken him approximately six years. Natural methane reduction measures are preferable to current treatments, such as feed antibiotics.

Hristov first screened hundreds of essential oils, plants and various compounds in the laboratory before arriving at oregano as a possible solution. During the experiments, oregano consistently reduced methane without demonstrating any negative effects.

Following the laboratory experiments, Hristov conducted an experiment to study the effects of oregano on lactating cows at Penn State's dairy barns. He is currently conducting follow-up animal trials to verify the early findings and to further isolate specific compounds involved in the suppression of methane.

Hristov said that some compounds that are found in oregano, including carvacrol, geraniol and thymol, seem to play a more significant role in methane suppression. Identifying the active compounds is important because pure compounds are easier to produce commercially and more economical for farmers to use.

"If the follow-up trials are successful, we will keep trying to identify the active compounds in oregano to produce purer products," said Hristov.

Hristov has filed a provisional patent for this work.

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1 / 5 (3) Aug 26, 2010
How much worse is methane than CO2 as a GHG? In reality, if either CO2 or CH4 (methane) is released into the atmosphere, they don't sit there forever causing global warming. Instead, they participate in natural reactions and disappear over time. The problem with additional CO2 is that it currently builds up in the atmosphere--more is produced and released into the atmosphere than is remove, for example, by trees and other plants.

What about methane? Methane in the atmosphere reacts to form CO2 plus water: CH4 + 2O2 --> CO2 + 2 H2O. Therefore, at worst, methane in the atmosphere causes as much global warming as an equivalent amount of CO2, plus an addition for the extra forcing before the methane is oxidized. If we assume that CO2 lasts about ten times as long as CH4 in the atmosphere, that makes CH4, at worst, 7 times "worse" than CO2.

But that ignores the time factor. Methane's contribution to global warming will be mostly in the decade after it is produced.
5 / 5 (1) Aug 26, 2010
How much worse is methane than CO2 as a GHG?
17,000x and then when it is broken down by UV (over time) it becomes CO2, H2, O2, and H2O.
But that ignores the time factor. Methane's contribution to global warming will be mostly in the decade after it is produced.
No, it begins contribution as soon as it enters the atmosphere, even a few inches from the ground.
1 / 5 (2) Aug 26, 2010
Skeptic_Heretic, not sure about the point of your last sentence, as methane is in the decade after it was produced the instant it is produced.
not rated yet Aug 26, 2010
Skeptic_Heretic, not sure about the point of your last sentence, as methane is in the decade after it was produced the instant it is produced.

He's erroneously assuming that Methane itself has no substantial radiative forcing and must breakdown into CO2 first.
not rated yet Aug 27, 2010
This could be great tech if it pans out! I’ve personally felt that reducing CH4 emissions is much more efficient on a $/Joule basis compared to CO2, and CH4 is a very large contributor compared to the amount of media and academic attention it receives.

CH4 is a much stronger GHG because the greenhouse effect works by light absorption, rather than the number of equivalents in the atmosphere. Solar energy is absorbed at various wavelengths by different gases. Molecularly, a photon of a specific wavelength strikes a GHG molecule (CO2, H20, CH4 etc.), exciting it. The GHG molecule then bounces into a different gas molecule (i.e. N2, O2), sharing its heat. While CO2 is much more persistent and abundant, CH4 absorbs a lot more solar energy per molecule, easily making up for its relative scarcity. Hope this helps!

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