Reducing methane emissions from cattle and sheep by more than two-thirds is unlikely to top many farmers’ priorities.

But when the feed additive responsible can also yield improved growth rates, it may suddenly become appealing.

Researchers at Aberdeen-based Rowett Research Institute say adding up to 10% fumaric acid to ruminant feeds can reduce the amount of methane produced.

John Wallace, head of the Rowett’s Microbial Biochemistry Group, says current research aims to discover whether results previously achieved in sheep can be replicated in cattle.

“In lambs, fumaric acid inclusion reduced methane production by 70% and increased feed conversion efficiency by 10%.”

Dr Wallace says reducing the amount of methane produced by cattle would be good news for the environment.

“Methane is a greenhouse gas and is a particular problem in countries such as New Zealand, where a large proportion of methane is produced by ruminant animals.”

New Zealand levies a carbon emission tax, so anything that can be done to reduce the amount of methane produced has to be good.

Keenan nutritionist David Hendy reckons the EU could soon follow suit.

“There are already rumours circulating in Holland and Denmark of the need for a methane quota, possibly within the next five or 10 years,” he says.

But the real bonus for farmers will be the 10% increase in efficiency gained by including fumaric acid in diets, says Dr Wallace.

“Hydrogen produced by one set of bacteria in the rumen is used by another group to produce methane.

Including fumaric acid in diets renders this hydrogen unusable, creating proprionic acid instead of methane.

“This is a precursor to the formation of amino acids and increases growth efficiency.

For every 1kg of feed consumed, the animals produce 10% more liveweight.”

And the banning of the antibiotic enhancer Romensin this year, which increased efficiency by up to 10%, means fumaric acid could fill a gap in the market, reckons Simon Marsh of Harper Adams University College, Shropshire.

“Bearing in mind that every 0.1 change in feed conversion ratio results in about a 5 increase in gross margin and that the FCR on a cereal beef system is typically 5:1, a 10% improvement should reduce FCR to 4.5:1.

That reduction could improve GM/head by 25.”

Dr Wallace believes a commercially available product could be on the market within three or four years, depending on demand.

However, fumaric acid must be offered in the right form because it can make diets unpalatable and increase the risk of acidosis.

“We have developed an encapsulated form which is released slowly in the rumen, avoiding the risk of acidosis and ensuring there is no taint that could make feeds unpalatable.”

However, some beef producers may have concerns about including such an additive, says farm manager Gary Gray of Beckhithe Farms, Norfolk.

“Because we are on contract with Waitrose and Marks & Spencer for our beef, there would be many criteria to allow such an inclusion, making it unfeasible.”

He also reckons the 10% increase in efficiency would not be enough to tempt him to consider feeding fumaric acid.

“We pride ourselves that our cattle are fed home-grown produce, so including promoters or additives would go against many of our policies.”

fwlivestock@rbi.co.uk