Researchers Find Way to Reduce Methane from Cows

 

Scientists in Mexico say they may have found a way to cut production of methane¹, a gas linked to rising temperatures on the Earth’s surface.

The scientists say their method may help reduce the methane released by cows, one of the main producers of the gas.

When talking about global warming, many people think of carbon dioxide, another heat-trapping gas. Studies have shown that large amounts of carbon dioxide in the atmosphere reflect heat back to earth, causing climate changes.

Methane is an even more powerful heat-trapping gas. Cows are known to produce high levels of methane when they eat and process food. Farm animals are responsible for 44 percent of all human-caused methane, according to the Reuters news service.

Researchers at the Autonomous² University of the State of Mexico are studying how a cow's diet affects the production of methane. The researchers are using a specially³ designed machine to measure the effect.

Stefanny Hernandez is an assistant researcher at the university. She told VOA that, "approximately 95 percent of methane that is emitted by cattle is from breathing.”

The scientists use the machine to try to capture the animal’s breathing to examine the methane released, she explained.

Most of the gas is released when cows belch⁴. The digestive bacteria in a cow’s stomach causes the animal to expel the gas through its mouth.

There are an estimated 1.3 to 1.5 billion cows in the world. Each animal releases as much as 120 kilograms of methane per year.

The U.S. Environmental Protection Agency reports that, when measured in pounds, the effect of methane on climate change is more than 25 times greater than carbon dioxide over a 100-year period.

In addition, a 2006 United Nations report found that raising cattle produces more greenhouse gases than cars and trucks combined. This includes not just gases released by the cattle, but the effect of related activities, such as clearing forests to raise the animals.

Octavio Castelán is the head of the university’s cattle and environment laboratory. He told VOA, “If we can reduce methane emissions⁵, then we can rapidly reduce the effect on climate change."

As it is difficult to capture the gas released by cows for use as energy, one way to lessen⁶ its release is to change their diet.

Scientists in some countries are looking for ways to decrease cow methane. But, Castelán explained, while they are trying different plants and chemical compounds, those products would be too costly⁷ and difficult to bring to Mexico.

The Mexican researchers have found two animal food sources offering promising⁸ results: leaves from the leucaena tree and the flowers of the cosmos⁹ plant. Both plants grow in warm climates.

The researchers found that cows who ate grass mixed with the leucaena leaves belched¹⁰ about 36 percent less methane than a diet of grass alone. The cosmos flower reduced these emissions by 26 percent when mixed with the animal’s feed.

In addition, the two plants do not have a harmful effect on milk and meat production. In fact, the researchers found that leuceana leaves improve the quality of cow milk. This can give Mexican farmers more reason to grow the plants and change their cattle’s diet.

Words in This Story

global - adj. of or related to the world

emit - v. to send gases, light, or energy out into the air

cattle - n. cows, bulls, or steers¹¹ that are kept on a farm or ranch¹² for meat or milk

belch - v. to let out air from the stomach through the mouth very loudly

greenhouse - n. a structure that protects plants and extends growing seasons

1 methane   

n.甲烷，沼气

参考例句：

• The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
• Methane may have extraterrestrial significance.甲烷具有星际意义。

2 autonomous   

adj.自治的；独立的

参考例句：

• They proudly declared themselves part of a new autonomous province.他们自豪地宣布成为新自治省的一部分。
• This is a matter that comes within the jurisdiction of the autonomous region.这件事是属于自治区权限以内的事务。

3 specially   

adv.特定地；特殊地；明确地

参考例句：

• They are specially packaged so that they stack easily.它们经过特别包装以便于堆放。
• The machine was designed specially for demolishing old buildings.这种机器是专为拆毁旧楼房而设计的。

4 belch   

v.打嗝，喷出

参考例句：

• Cucumber makes me belch.黃瓜吃得我打嗝。
• Plant chimneys belch out dense smoke.工厂的烟囱冒出滚滚浓烟。

5 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

6 lessen   

vt.减少，减轻；缩小

参考例句：

• Regular exercise can help to lessen the pain.经常运动有助于减轻痛感。
• They've made great effort to lessen the noise of planes.他们尽力减小飞机的噪音。

7 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

8 promising   

adj.有希望的，有前途的

参考例句：

• The results of the experiments are very promising.实验的结果充满了希望。
• We're trying to bring along one or two promising young swimmers.我们正设法培养出一两名有前途的年轻游泳选手。

9 cosmos   

n.宇宙；秩序，和谐

参考例句：

• Our world is but a small part of the cosmos.我们的世界仅仅是宇宙的一小部分而已。
• Is there any other intelligent life elsewhere in the cosmos?在宇宙的其他星球上还存在别的有智慧的生物吗？

10 belched   

v.打嗝( belch的过去式和过去分词 )；喷出，吐出；打（嗝）；嗳（气）

参考例句：

• He wiped his hand across his mouth, then belched loudly. 他用手抹了抹嘴，然后打了个响亮的饱嗝。
• Artillery growled and belched on the horizon. 大炮轰鸣在地平面上猛烈地爆炸。 来自《现代英汉综合大词典》

11 steers   

n.阉公牛，肉用公牛( steer的名词复数 )v.驾驶( steer的第三人称单数 )；操纵；控制；引导

参考例句：

• This car steers easily. 这部车子易于驾驶。 来自《简明英汉词典》
• Good fodder fleshed the steers up. 优质饲料使菜牛长肉。 来自辞典例句

12 ranch   

n.大牧场，大农场

参考例句：

• He went to work on a ranch.他去一个大农场干活。
• The ranch is in the middle of a large plateau.该牧场位于一个辽阔高原的中部。