BC3. Basque centre for climate change – Klima aldaketa ikergai

UK scientists in 2010 developed a way to measure how much methane cows produced.

UK scientists have been looking at how changes to the diet of cows and sheep could help reduce the animals' greenhouse gas emissions.

The study suggested that certain feedstocks, in proportion to milk or meat yields, could reduce the release of methane by up to 33%.

According to latest figures, the agricultural sector accounts for about 43% of the nation's methane emissions.

Ministers hope the study will improve the environmental performance of farms.

"It is very exciting that this new research has discovered that by simply changing the way we feed farm animals we have the potential to make a big difference to the environment," said Agriculture Minister Jim Paice.

According to the Department for Environment, Food and Rural Affairs (Defra) - which funded the study - the farming industry accounts for 9% of the UK total greenhouse gases, half of which comes from sheep, cows and goats.

The research was carried out by a team from the University of Reading and Aberystwyth University's Institute of Biological, Environmental and Rural Sciences (Ibers), showed how it was possible cut environmental impacts from livestock. For example:

increasing the proportion of maize silage from 25% to 75% in a short-term trial was found to reduce methane (per kg milk) by 6%
high-sugar grasses could reduce an animal's methane emissions by 20% for every kilo of weight gain
naked oats could reduce methane emissions from sheep by 33%
But Defra added that the long-term benefits of the savings would have to be "considered against other environmental impacts as well as how practical or costly they are for the farming industry to implement".

It is also not clear whether these measures actually reduce emissions from the animals, or whether the dietary changes increases the overall yield therefore reducing the proportion of methane produced per kilo of meat or litre of milk.

Chewing the cud

The quest to reduce the impact of livestock on the environment and atmosphere is not new.

Since the turn of the century, researchers in New Zealand and Australia have been considering ways to tackle the problem of potent burps from ruminants.

In New Zealand, livestock account for 90% of the nation's methane emissions, and about 43% of its greenhouse gases from human activities. In short, without coming up with a solution, it would struggle to meet its Kyoto Protocol targets.

Last year, the UN Food and Agriculture Organization (FAO) suggested taxing animal emissions as part of a range of measures to reduce the impact from the global agriculture sector.

When the entire food chain was taken into account (rearing, feedstock, transportation, slaughter etc), the FAO estimated that the world's livestock accounted for about 9% of human-induced CO2 and 37% of methane emissions.

UK farming representatives are against the tax idea, saying that they have already taken measures to reduce overall emissions.

An alternative measure, outlined by researchers from the University of Bangor, could be to house dairy cattle in sheds, which would allow farmers to harvest the methane as a fuel source and prevent it escaping into the atmosphere.