Change in diet may reduce cow methane release: study

New York: Cows that eat corn and wheat produce less methane - a greenhouse gas 28 times more potent than carbon dioxide - as compared to grass-fed animals, a new study has found.

Octavio Castelan-Ortega, veterinarian from University of Mexico State measured that 90 per cent of cow methane comes from their front ends. Castelan-Ortega monitored the respiration of cows and found steep reductions in methane when cows were fed a diet enhanced with certain plants. In a study at four sites in Mexico, researchers found cows that fed on grasses mixed with the leaves of delicate tropical leucaena trees belched about 36 per cent less methane than
those on a straight grass diet.

The cosmos flower, with the Latin name Cosmos bipinnatus, reduced methane emissions 26 per cent when it was added to feed. The diet including leucaena tree leaves also improved the cow's milk production. Both plants contain bacteria-killing tannins that disrupt fermentation without interfering with a cow's digestion.

Too much of the plants would be toxic, but a small proportion seems to be beneficial. We drink tannins all the time. They are the bitter compounds in coffee and tea. The study was a pilot project using plants from the tropics and other warm regions.

Castelan-Ortega said researchers could identify and test tannin-containing plants from cooler climates. A small tweak in diet could result in a big reduction in
greenhouse gases from the world's growing population of cows. Many creatures, including humans emit methane from time to time. Microbes within our guts break down one substance and turn it into another, making methane in the process.

Scientists study methane because of its ability to warm the world - methane is 28 times more potent than carbon dioxide as a greenhouse gas. Cows are one of the largest sources of man-caused methane. Livestock around the world contribute 44 per cent to methane emissions attributable to the actions of humans, researchers said.