TOKYO -- Cow burps expel large amounts of methane, a gas with 25 times the greenhouse effect of carbon dioxide and a significant global-warming contributor. But one research team is working toward achieving decarbonization by trying to eliminate 80% of cow belches' methane content by 2050.
Cow stomachs have four compartments; after they swallow food such as hay or corn, they repeatedly ruminate, or regurgitate, to chew it further. The rumen, its largest stomach compartment, is a "fermentation tank" home to about 8,000 types of microorganism which digest difficult-to-decompose fibers. This process generates methane-filled fermentation gas belches.
"It is estimated that one dairy cow produces burps about 1,800 liters a day, with methane gas accounting for around 500 liters," said a National Agriculture and Food Research Organization representative.
According to the Ministry of Agriculture, Forestry and Fisheries, in fiscal 2019 the agriculture, forestry and fisheries sector produced greenhouse gases equivalent to about 47.47 million tons of carbon dioxide. Of this, 7.56 million tons, some 15.9%, was due to "fermentation in the digestive tracts of livestock" -- or cattle's belches.
Project team head Yasuo Kobayashi is a professor of animal function and nutrition at the graduate school of Hokkaido University. Referring to the research he has done since the 1980s, Kobayashi said, "For nearly 50 years now reduction of cow burps' methane has been sparsely studied by a handful of researchers."
The research's focus was initially unrelated to averting global warming, but rather on finding ways to reduce cattle feed. Basic research was apparently going ahead under the impression that if energy used in digestion to produce methane could be saved, cattle might be raised with less feed.
A turning point came for the field in 1995 with the establishment of the United Nations Framework Convention on Climate Change, which recognized cow burps as a factor in global warming.
Kobayashi's research goal of an 80% methane reduction by 2050 was adopted in 2020 by the government's system to support research and development leading to technological innovations that overturn common perceptions.
"There are three research subjects," explains Kobayashi. First is the discovery of new ingredients to add to cattle feed. In previous studies, liquid produced from squeezed cashew nut shells was mixed with feed to reduce methane by up to 20%. But the nuts are procured from Southeast Asia, making widespread uptake of the practice difficult.
Currently, the team is investigating some 20 new ingredient candidates that can be more cheaply obtained in Japan. Kobayashi said, "We are focusing on chemical substances used as food additives. Mass production at factories is possible, and it seems we could commercialize them cheaply in future."
The second task is breeding low methane cattle. Methane amounts exhaled differ by animal, with some expelling less methane even when eating the same food. "Since these are inherited characteristics, we can expect a 10 to 15% methane reduction by improving the breed," explained Kobayashi.
The hurdle is that breed improvement takes many years. Kobayashi is devising a long-term strategy, saying, "For the time being, we are trying to gradually make low methane cattle mainstream while suppressing methane by mixing new ingredients into feed."
But an 80% reduction is apparently difficult to achieve with just these two methods. Kobayashi's last resort, the third task, is to develop a small capsule-type device that when swallowed by a cow goes to their stomach and measures in detail the fermentation state inside. It then transfers the data for researchers to see.
Their aim is to analyze the data to discover what feed amounts and timings suppress methane generation, and to establish optimal feeding methods. If the knowledge is then applied to an automatic feeder, then work pertaining to feeding could also be reduced along with methane suppression.
Kobayashi expressed enthusiasm for the device's development, saying, "I want to make it popular by having it sell for about several hundred yen by around 2040 at the earliest."
Is an 80% reduction actually possible? Kobayashi said, "To be honest, it was just a dream at the beginning, but further discussions with project members have made it more realistic. We can at least achieve a 50% reduction."
Perhaps the day when cows can burp in an environmentally-friendly way is approaching.
(Japanese original by Taiki Asakawa, Tokyo Business News Department)