New diets for cows and sheep could reduce their greenhouse gas emissions, research funded by the Department for environment, food and rural affairs (Defra) shows.

Feeding the animals maize silage, naked oats and higher sugar grasses could reduce the amount of methane they produce, the study by Reading University and the Institute of Biological, Environmental and Rural Sciences showed.

Agriculture accounts for around nine per cent of all British greenhouse gas emissions. Most of this comes from sheep, cows and goats.

Farming accounts for 41 percent of Britain's overall methane emissions, which are harmful to the environment.

A trial showed that high-sugar grasses could reduce an animal's methane emissions by 20 percent for every kg of weight gain and naked oats could reduce methane emissions from sheep by 33 percent.

"In the longer term the benefits gained by changing animals' diets will need to be considered against other environmental impacts as well as how practical or costly they are for the farming industry to implement," Defra said in a statement.