A feed supplement that limits the methane released by belching and flatulent animals could dramatically reduce Ireland's methane emissions, writes Dr Marina Murphy
Curbing what comes naturally in cows may help Ireland reach strict greenhouse gas emissions set under the Kyoto agreement. Researchers in Scotland have developed a new feed additive that reduces flatulence and belching in ruminants and this in turn lowers methane gas emissions.
The researchers say that the feed additive improves growth efficiency and could help farmers in countries with large agricultural sectors, such as Ireland, avoid greenhouse gas emission taxes in the future.
Flatulence from cows, and also sheep and other ruminants, is a serious environmental problem. It accounts for about 15 per cent of world-wide emissions of methane, the most potent of the greenhouse gases. There have been moves in some countries to tax farmers on the emissions produced by their livestock.
"The possibility of carbon-emission taxes, such as that mooted in New Zealand, may seem far-fetched at this moment, but it will certainly happen in some countries," says John Wallace at the Rowett Research Institute, where the feed is being developed.
"Much of the greenhouse gas emissions in Ireland come from agriculture. If carbon emission taxation comes to Europe, our feed additive could be doubly beneficial - improving productivity, while avoiding the emissions tax," he says.
Field trials with growing lambs revealed that the supplement reduces emissions by 70 per cent and delivered 10 per cent improved feed efficiencies. For every kilogram of feed they get, the animals gain 10 per cent more body weight. "A reformulation seems to be required with cattle, which we intend to carry out in the next 12 months," Wallace says.
The new supplement contains fumaric acid. The presence of this acid means that hydrogen, one of the substances used in methane gas formation, is metabolically trapped in the cow. Because it is unavailable for reaction, methane formation is prevented.
The fumaric acid is converted to propionic acid in the process. Propionic acid is one of the normal products of rumen fermentation. It is absorbed and used for the synthesis of glucose and amino acids.
Methane is a high-energy fuel - we use it for domestic cooking. "When methane formation is inhibited, you can imagine that the energy is retained in the animal rather than being lost to the atmosphere," explains Wallace.
The supplement, which will be suitable for all feedlot cattle, all dairy cattle, and all animals that receive compound feeds, has produced the most impressive results to date in the effort to reduce agricultural emissions. "Nothing has given this response before," says Wallace. "A short-lived decrease of 20 per cent is about the best that can be achieved by other methods," he says.
Because the feed needs to be administered on a daily basis, it will be of no benefit to hill-grazing sheep or cattle.
The improved feed efficiency rather than the environmental benefit will be what sells the additive to farmers, Wallace points out. But the effect on carbon emissions may become more important as Ireland struggles to meet its commitments under the Kyoto treaty.
The Kyoto treaty, signed in 1997, commits 154 industrialised countries to reduce their combined emissions of a basket of six greenhouse gases by at least 5 per cent compared to below 1990 levels by the first commitment period 2008-2012. The protocol came into force on February 16th, 2005.
Ireland agreed to limit its greenhouse gas emissions to 13 per cent above 1990 levels by 2008-2012, according to the Department of the Environment, Heritage and Local Government.
Ireland has a population of six million cattle and even more sheep. Each cow can produce about 500 litres of greenhouse gases every day. In Ireland, agriculture is thought to account for some 38 per cent of the country's greenhouse gas emissions.
In New Zealand, methane emitted by farm animals is thought to account for more than half of that country's emissions. New Zealand has already introduced a carbon tax, which is expected to add 6 per cent to household energy prices and 9 per cent for most businesses. In 2003, the government there planned to impose a methane tax on farmers, but so far, plans have been placed on hold, not least because farmers labelled it a "fart tax".