Reducing methane emissions presents challenges and opportunities
There are a whole range of strategies that will help to reduce methane emissions from livestock and these provide scientists and livestock farmers with both a challenge and an opportunity.
That was the good news presented to delegates attending this year’s British Society of Animal Science annual conference by Jamie Newbold, Aberystwyth University.
“There’s plenty of technology that we can develop and apply on farm that will not only reduce methane emissions, but will also increase livestock productivity,” he said, adding that methane emissions represent a 10% loss of energy from the animal.
“Reducing emissions allows us to retain some of that energy and, therefore, boost production efficiency.”
Looking at rumen function to reduce emissions was one key option as rumen bugs excrete hydrogen and this combines with CO2 to produce methane.
Dietary supplements can be added to inhibit methanogenesis: “But the rumen bugs can quickly adapt to chemical additives so we’re looking at those with longer term effects,” said Professor Newbold.
He added that plant extracts, such as allicin derived from garlic, can dramatically reduce methane production. “Allicin actively inhibits methane producing bacteria in the gut. And Chinese rhubarb has a similar effect.
“Either extract, and others being currently being investigated, offer livestock producers with a real opportunity to keep energy in the rumen and, therefore, in the animal.”
Other rumen ‘approaches’ include vaccinating the rumen against methanogenic bacteria. Trials are on-going in Australia and although the technique does reduce methane emissions it’s not very effective at the moment. “There’s hope that the technology and the results will improve with more development,” Professor Newbold told delegates.
Since hydrogen plays a key role on methane production, other methods have looked at limiting hydrogen production in the rumen, by removing protozoa, or capturing hydrogen, by feeding organic acids that lock up the element. Again trials have shown a significant reduction in methane production in both instances, but more research is needed.
“And we also have to look into the net benefit of some of the methods of reducing methane emissions as some, themselves, would result in additional CO2 emissions and could also have a huge economic cost.
“If we took the allicin option, for example, there wouldn’t be any cows to feed it to as we’d need all the land they graze to grow garlic,” added Professor Newbold.
“Other techniques such as weaning lambs on concentrate feed, which has shown potential in trials to reduce the rumen population of methane producing bacteria in sheep, would be preferable in this instance.
“There’s also a real possibility that genetic selection for reduce methane production could be an option in the future.”
Presented to the British Society of Animal Science Annual Meeting, March 31 to April 2, 2008, Scarborough, UK.
Full details: CJ Newbold: “Redressing the balance: ‘less belching cows’.”
Presentation_293newbold (pdf)
PDF of Powerpoint presentations available at http://www.bsas.org.uk/Members_Area/
For further details contact cjn@aber.ac.uk
