Science - October 30, 2019

Climate-friendly cows require methane inhibitors

Albert Sikkema

A new feed additive developed by DSM inhibits the emission of the greenhouse gas methane by cows, like adding nitrate to the feed does. Animal feed researcher Jan Dijkstra outlines the effect and possibilities.

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‘The effectiveness of Bovaer – DSM’s product that inhibits methane synthesis – will soon be tested at the Dairy Campus, the research and innovation centre for the dairy farming at Wageningen Livestock Research’, Dijkstra says.

‘This testing is necessary to include the product in the Kringloopwijzer (“Circularity Guide”), the tool dairy farmers use for mineral management. The guide estimates the volume of greenhouse gases the cows produce based on the amount of feed concentrates, grass and silage maize content used in their rations. WUR researchers are currently testing how much methane emissions drop for various feed rations. Farmers can then use those figures when using the Kringloopwijzer.’

What will this research yield?
‘When using Bovaer with the Dutch ration, methane emissions are expected to drop by around 20 percent. This is less than the 30 percent DSM claims based on international research. That is because Dutch rations contain a lot of fibre. The product becomes less effective with more fibre. Bovaer might become available by the end of next year. It is currently being assessed by the European Food Safety Authority, EFSA.’

Would adding nitrate help as well?
‘When nitrate is added to the feed, bacteria convert nitrate into ammonia, resulting in less methane. This process was investigated at WUR’s experimental farm De Marke. This takes a different approach to Bovaer. Bovaer is a molecule that binds to an enzyme that forms methane in the rumen of the cow; it stops the enzyme’s activity. Only 0.06 grams per kilogramme of feed is required. But nitrate is needed in much higher amounts. To achieve a methane reduction of 10 to 15 percent, 10 to 15 grams of nitrate per kilogramme of feed is needed.’

Could Bovaer be combined with nitrate?
‘We do not yet know whether the effects of Bovaer and nitrate stack, thus achieving a 30-35 percent reduction in methane emissions, or whether there are interactions between the two substances. In any case, the two can aid in achieving a substantial decrease. Nitrate is naturally contained in grass silage, but the pure additive is supplied by the agro company Cargill. Cargill is also researching this methane inhibitor for the Kringloopwijzer.’

Will this be sufficient to achieve the climate goals?
‘Livestock farms are required to cut methane emissions by half in the coming years. These additives will allow farmers to make good progress in that direction. But it takes money, so the milk price will have to increase somewhat.’

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  • Jan Dijkstra

    Met 'toevoeging van nitraat' wordt bedoeld dat stikstof uit rantsoen vervangen wordt door stikstof uit nitraat - netto evenveel stikstof in rantsoen dus. Ammoniak, gevormd uit bijvoorbeeld afbraak van eiwit of van nitraat in de pens, kan door micro-organismen in de pens weer gebruikt worden om aminozuren en uiteindelijk eiwit te vormen. Dus geen verhoging ammoniak uitstoot.

  • Freek

    Remming van een methaanvormend enzym klinkt OK, maar Nederland zit echt niet te wachten op verhoging van de ammoniakuitstoot ('stikstof') door het toevoegen van nitraat aan veevoer. Het nog verder verhogen van gewas-eigen nitraat in gras en ander veevoer heeft ook dat onzalige effect. Niet doen dus; spaar de kool én de geit.

    20-25 % reductie van methaan door Bovaer en andere maatregelen, lijkt haalbaar. Wel eerst zien en dan geloven. We kunnen op korte termijn alvast een 25% krimp van de rundveestapel inzetten als minste vereiste om de beoogde 50% methaan-reductie te behalen. De Nederlandse consument hoeft er geen druppel zuivel om te laten; koop s.v.p. verantwoorde zuivel voor een dubbeltje meer.