More research needed to use methane-reducing additives in grazing systems

Eric Barker, 23/08/2022

Raw dried Asparagopsis seaweed before it is refined into a feed supplement.

THE development of methane-reducing feed additives has promised plenty to the cattle industry in recent years, with two products now circulating and commercial trials in feedlots.

But using seaweed asparagopsis and Bovaer (3-NOP) in grazing systems is still proving to be a challenge, with a University of Melbourne researcher telling a webinar this afternoon that more research is needed to make it practical for producers.

Ainslie Macdonald said there was no completed research into using feed additives in grazing systems. She said results from some current studies were on the way.

“There is currently a study using lick blocks and slow-release pellets that’s aiming to see if 3-NOP is consistently available in the rumen,” Ms Macdonald said.

“The results of that study are coming out next year and I think that will really guide where grazing research goes. In terms of asparagopsis, there is research going into whether it can be put into lick blocks and molasses.”

Ms Macdonald said making sure animals were consuming the recommended amount of feed-additive was one of the biggest challenges.

“This is why the supplements are so well suited to feedlots because you know exactly what you are feeding the animal,” she said.

“There’s a study on grazing sheep happening at the moment and the sheep either don’t want it or they eat too much of it. That’s why I think slow-release pellets or lick blocks where you can limit access or even early-life interventions are really promising.”

More research on the way

Water medication has also been thrown into the feed-additive conversation, which Ms Macdonald said was under-researched.

“There is more research needed to see whether it can be fed through water and if it can be fed to calves to reduce methane in the early stages of life,” she said.

“Two studies looking at turning asparagopsis into oil are coming out soon, some looking slow release technologies.”

Ms Macdonald said there was also more demand for research into using 3-NOP and asparagopsis with sheep and goats.

“So many people I speak to ask for more studies on sheep and goats,” she said.

“As the research on cattle develops and there is more similarities drawn to sheep and goats, there will be more a shift towards small stock.”

Are there unintended consequences?

The environmental footprint involved in processing the feed-additives and possibly creating more emissions in the manure are two of the main issues raised about the products.

Ms Macdonald said the possibility of increasing methane in manure was dependent on soil-type.

“Only one study has been published on the impact of 3-NOP on manure and soil and they did not find anything substantial or anything they felt had increased,” she said.

“But there needs to be further studies on this, especially with asparagopsis because its impact on manure and soil has not been studied.”

While seaweed asparagopsis is native to Australia, Ms Macdonald said there was potential issues with the way it will potentially be farmed in open ocean.

“It does increase plastic pollution, harvests are season and as climate change increases the temperature of water there is a concern that asparagopsis will outcompete other species,” she said.

“With processing, the biggest problems are the greenhouse gas emissions with freeze-drying it or emulsifying it into oil. There are also greenhouse gas emissions associated with transporting it.”



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  1. DEBORAH NEWELL, 26/08/2022

    The key cyclical management of our planet’s CH4 rests with prokaryotes called methanotrophes. Methane is belched by oceans from seafloor volcanic rifts, from above ground volcanoes even after they have ‘blown’, from fissures in deep mines, sink holes and caves as well as by cattle belches and human flatulence. It is part the atmospheric-to-mantle cycle on our planet. So there are gaseous expulsions of methane from deep into our planet, deep swamps/bogs/hot springs and local expulsions from the methanocytes in the guts of ruminant animals and humans etc…
    What destroys or limits these simple, methane devouring prokaryotes is too much soil nitrogen. This comes from mono-culturing vast tracks for lucernes and soy beans et al and from applying NKP fertilizers. It is the fertilizer use for cereal monocultures that cause the most damage to this natural feedback loop provided by methanotrophs AND NOT BOVINE or other ruminant production off pastures. Once in a feedlot the story isn’t as simple as there is the double-up of methane from the animals digestive system’s methanocytes added to the soils methanotroph destruction caused by NKP and high legume feeds needed for intensive feed industries.

  2. Rod Kater, 26/08/2022

    Did anyone consider that asparagopsis might decrease methane production by damaging the rumen, due to its formation of bromoform in the gut, a close relation to chloroform, no longer used in humans?

  3. Peter Dunn, 23/08/2022

    Putting aside the reality that it is not going to make a scrap of difference in the context of the increases in emissions by the major global emitters, together with the European shift created by an incompetent rush to renewables, it is refreshing to read a report that tells it like it is. There is clearly a long way to go with this research. If ultimately it is determined that going down this road will make a difference, then better to listen to this researcher than the snake oil sales teams. In the meantime, money could be better spent protecting against FMD, building water infrastructure, fencing or any other genuine ag. improvement.

  4. Adam Coffey, 23/08/2022

    Directly reducing emissions from ruminant animals seems to be the sexy thing to chase. I have serious doubts as to the net benefit of these products not to mention additional costs to producers. Unless there is a substantial production benefit who is going to use these products? Even if there is a potential production increase uptake will be limited (see northern P supplementation, or lack thereof).
    How about we all take a step back and think about the bigger picture – land management. Teach people to manage their grass, build organic matter in their soils, increase species diversity and legume content, manage their water cycles – rehydrating landscapes and building resilience for dry times. All whilst increasing carbon sequestration and building profitable businesses.
    Not as simple to quantify and subsequently not as sexy – but this is where the real net benefit to the environment lies.

  5. David+Dwyer, 23/08/2022

    Reducing CO2 in ruminant production will be a whole farm solution, so many parts will add to the required outcome ( MLA CN30 if this is the target ).
    Supplements will just be part of the equation.

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