Bengaluru: A US scientist says India has a huge potential to reduce its carbon footprint -- which leads to global warming -- by exploiting the results obtained from research conducted by his team on dairy cows. Still, there's a long way to go.
Ermias Kebreab, Professor in the Department of Animal Science at the University of California-Davis, recently showed that feeding seaweed as a dietary supplement to the cows dramatically reduced their emissions of methane gas.
Methane in the atmosphere is a greenhouse gas (GHG) 28 times more powerful than carbon dioxide (CO2) in its potential for global warming. According to India's Ministry of Environment and Forests, about one eighth of all GHG emissions from India -- 1,728 million tons of CO2 equivalent -- came from its cattle population in 2007.
According to the US Department of Agriculture, India's 305 million cattle population is the largest in the world in 2018 followed by that of Brazil (233 million) and China (97 million).
Cows are "ruminant" animals that burp as they digest food in their rumen, a part of the stomach. The rumen is home to millions of microbes that help ferment and break down high-fiber food like grass and hay, producing gases that combine to form methane which the cattle perpetually burp and emit.
In their controlled experiment, Kebreab's team tested the efficacy of one kind of marine macro-algae called "Asparagopsis" on 12 Holstein cows.
They blended the dried seaweed with molasses to produce a shiny, viscous meal that the cows evidently found tasty. An open-air device measured the methane in the cows' exhaled breath as they ate.
The three-month study found that spiking the cows' regular diet with Asparagopsis, reduced their methane production by 58 per cent. The seaweed, that has been called "green feed" is believed to inhibit an enzyme in the cows' stomachs that contributes to methane production. According to a statement from the University, the results obtained "are promising, but not final".
The finding should be encouraging news to India that has a long stretch of coastal waters where the seaweed can be farmed rather than having to grow it inland. Growing seaweed doesn't require land, fresh water or fertiliser.
"I agree India has a huge potential in this area (to reduce its greenhouse gas emission)," Kebreab told this correspondent in an email. Asked about possible collaboration he said: "We are at the early stage of doing some research and not really ready for collaboration. However, in a year or two, that is a possibility."
Kebreab's work builds on initial studies in the laboratory carried out in 2014 by a team of researchers at James Cook University in Australia which indicated that a small amount of seaweed practically eliminated methane emissions from cow gut microbes.
Researchers worldwide are working on the livestock methane problem. According to reports, Irish farmers are hoping to create seaweed-eating "super cows" in a bid to fight climate change. India, in spite of the largest inventory of cattle in the world, is yet to mount a major programme on this.
According to the website of the Indian Veterinary Research Institute (IVRI) in Izatnagar, "several compounds of herbal origin to reduce methane production in animals have been identified", but IVRI research director B.P. Mishra did not
respond to request for information on any publication of its work.
Canadian researcher Karen Beauchemin and co-workers have reported that most of the research findings to date are based on a limited number of animals and short-term feeding periods.
"Thus, substantial research is still required to bring dietary manipulation forward as an effective strategy for GHG mitigation," Beauchemin noted.
Felix Bast, Assistant Professor in the Department of Plant Sciences of the Central University of Punjab in Bathinda, agreed.
"It is well-known that seaweed in cattle fodder could lower methane," he told told this correspondent in an email.
"My only concern is that this news from the University of California-Davis lacks any backing with published paper. Nothing is confirmed unless authors publish it," Bast maintained.
Kebreab admitted he has much more research to do to determine if seaweed supplements could provide a viable, long-term solution. "But we are very encouraged by these early results," he noted.
(K.S. Jayaraman is a veteran science journalist.)