Tokyo Researchers have stumbled on a way to stop cows from emitting methane - a potent greenhouse gas - when they belch, a finding that could help the fight against global warming.
Methane generated when livestock belch while eating is said to account for about 5 percent of global greenhouse gas emissions. But supplementing the animals' diet with cysteine, a type of amino acid, and nitrate can reduce the methane produced by the animals, according to the researchers.
Methane is generated in the stomachs of ruminants, such as cows and sheep, as bacteria breaks down plant fibers. The gas is emitted into the atmosphere when the animals belch as they chew cud.
The research team at Obihiro University of Agriculture and Veterinary Medicine in Hokkaido, headed by professor Junichi Takahashi, initially noticed that dairy cattle that consume a large amount of nitrate from grass growing in soil doused with high levels of chemical fertilizer release only traces of methane when they belch.
The researchers stumbled on the relationship between nitrate and methane generation when they studied a mass poisoning outbreak among a herd of cows.
The team found that feeding the animals cysteine in addition to nitrate not only significantly cut the methane they generate, but also helped prevent them from being poisoned.
The study also showed the nitrate does not affect milk quality. The amount of cysteine a cow needs each day costs about 100 yen (about 95 cents U.S.), according to the researchers.
The university team has obtained a patent for the technique in Japan, the United States, Australia and two other countries.
Methane is about 20 times more effective than carbon dioxide in trapping heat in the atmosphere.
European and Oceanian countries, where dairy farming is prosperous, are also researching how to reduce methane generation by livestock. The New Zealand government even subsidizes research on the subject.
According to the Environment Ministry, of the 23.8 million tons of methane emitted in Japan in 2006, 6.78 million tons was apparently produced by cows.
Livestock feed manufacturers hope to tap the technique to make new feeds that will help combat global warming.
Before the Group of Eight summit meeting at the Lake Toya hot spring resort in Toyakocho, Hokkaido, the research team plans to hold a symposium in June to introduce the technique to researchers from overseas.
Osamu Enishi, head of the Livestock Research Team on Global Warming at the National Institute of Livestock and Grassland Science, said the discovery has great promise.
"Cows produce a surprisingly large amount of methane. I think this technique will enable dairy farmers to reduce methane generated by cows without jeopardizing the cattle's productivity or the quality of their meat and milk," Enishi said. "Other Asian countries have many cows and other livestock animals, so this discovery could help countries worldwide combat global warming."