Jul 15, 2009 8:17 am US/Eastern
Belching Up A Warmer Planet, Cows & Climate Change
BOSTON (WBZ) ―
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The average cow releases 200 to 400 pounds of methane each year.
CBS
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About 80% of a cow's methane is released from burps. The rest comes out the rear.
CBS
"MOOOO--ve" over cars and trucks. According to the United Nations, four legged cows could pose a greater threat to our atmosphere than four wheeled vehicles.
It's a problem that comes right from the gut - quite literally.
METHANE BUILD-UP
"Bacteria and protozoa in a cow's stomach digest forages (grasses) and produce nutrients they can use," said Dr. George Saperstein of Tufts University Cummings School of Veterinary Medicine. "One of the byproducts of that fermentation process is a number of gases, among them is methane."
About 80 percent of that methane comes out as a belch. The rest sneaks out the back-end, so to speak.
BEEF CATTLE VS. DAIRY COWS
"Beef cattle are bigger offenders than dairy because there are more of them," explained Dr. Saperstein, "and they eat grasses versus grains which more readily release methane during digestion."
"But the grain is $350 a ton versus grass which is free," added Scott Brundage, herdsman for the Tufts University herd.
Pound for pound, methane is 20 times more effective at trapping incoming solar radiation than carbon dioxide, but stays in the atmosphere a much shorter time.
JUST HOW MUCH METHANE?
The average cow releases 200 to 400 pounds of methane each year. Sheep and goats are emitters too. "It's how God made them. It's what they are. It's what they do; you can't change Mother Nature," said Brundage. But scientists may try to do just that.
Cows, goats, and sheep account for one-third of global methane emissions. Now scientists are experimenting with dietary changes to alter emissions.
"When cows are on pasture eating grasses, they are emitting the most methane," said Dr. Saperstein. "When dairy cows are fed high grain diets - that actually reduces their emissions. Feeding fats in general, and omega 3s specifically, has also been shown through research to reduce methane production," he said. In fact, it can cut it by as much as 18 percent.
SUSTAINABILITY
"But I don't know how sustainable these supplements are," Dr. Saperstein added. "Organisms are very adaptive and it might not work for long. Too much fat would reduce the production of the cow and could upset their stomachs too."
Genetics might one day offer another way to curb the burps. "Geneticists can, through selection, in theory create lines of sheep that produce less methane. It is also thought that different breeds of cows may emit less methane," said Dr. Saperstein. "But I don't think it is a system that is really broken." "
THE PEOPLE PROBLEM
I don't get how people can be concerned about methane from a cow when we have SUVs and jet planes emitting a whole lot more. I think our priorities are a little askew," said Brundage.
"There's a lot bigger threats to our climate based on human activity than there is from livestock," Dr. Saperstein agreed. "The best of all worlds would be if we could somehow capture the methane and use it for energy to power a farm - cow power!"
TURNING THE TABLES ON METHANE
Some farms in New England are doing just that. They are turning the tables on methane by turning manure into electrical power. Although that technology is yet to come to farms in Massachusetts, this option is being closely investigated.
With so much methane in the air, the American Dairy Industry is taking steps to make cows more "green", searching for ways to reduce total industry emissions by 25 percent in the next decade. But this move is not motivated by government regulations. Politicians have opted to "pass" on the gas. Belches from cows and other farm animal emissions will not be regulated under the new climate change legislation.
(© MMIX, CBS Broadcasting Inc. All Rights Reserved.)
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