We’re feeding seaweed to cows to help reduce methane emissions in livestock, and to secure the sustainability and profitability of the livestock sector.
Two cattle in a pen.
We’re working to reduce the methane emissions of livestock.

We’re researching the benefits of feeding cattle seaweed. It’s one of a number of promising lines of our research that have the potential to significantly reduce greenhouse gas emissions from Australia’s $17 billion livestock sector.

Australia is a major producer of livestock, and livestock in Australia are responsible for about 10 per cent of the country’s overall emissions. Livestock also contribute to 60 per cent of all emissions from the agricultural sector. As a greenhouse gas, methane is 28 times more potent than carbon dioxide (CO2) over 100 year timeframes.

To combat this issue, we’re working on multiple approaches that could provide significant reductions in greenhouse gas emissions for the agricultural sector. Both in intensive and pasture-based systems.

Methane-busting seaweed

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

One potential solution is feeding livestock seaweed. Scientists have found the common Australian red seaweed (Asparagopsis taxiformis and A. armata) virtually eliminates methane emissions in cattle and sheep. This is when it is fed as a dietary additive in low doses.

How does seaweed reduce methane? The metabolites in the seaweed disrupt the enzymes that are responsible for the cattle and sheep producing methane in the rumen (stomach).

And how much seaweed is enough? Studies in cattle and sheep have shown these results are possible when seaweed is included as one per cent or less of the dry diet.

The discovery was made in collaboration with Meat & Livestock Australia and James Cook University, with ongoing research currently underway to understand the optimal feed mixes.

The methane-busting seaweed feed could be commercialised within two years. However, wider adoption (across Australia and overseas) is dependent on establishing a new industry to farm Australian red seaweed at an industrial scale. The possibility of open line seaweed farming is being explored in southeast Asia and elsewhere.

The seaweed option is very promising for cattle in feedlots (about one million cattle in Australia) and dairy cows (about 1.6 million in Australia).

However, applying the feed supplement to cattle grazing on open pasture is logistically challenging. Cattle graze over vast areas, but they have to be fed seaweed every day. There is a need to do more research into technologies that can deliver the seaweed and other methane-reducing feeds to grazed livestock systems to create a solution for all livestock producers.

Beyond seaweed: less burps with legumes

To work around the logistical problems of feeding seaweed supplements, we have been studying whether the amount of methane produced by cattle decreases when they’re fed two tropical legume species: Leucaena and Desmanthus. Both plants not only reduce methane but also boost animal growth.

Compounds in these plants act on the microbes in the rumen in a similar way to the Asparagopsis seaweed. However, the effect is smaller, at around a 20 per cent reduction in methane emissions.

While the effect is smaller, it shouldn’t be discounted. These legumes could be planted into grazing systems now, so that they’re available to livestock in the near-term. They could feed many more of the 24 million beef cattle in Australia. A 20 per cent reduction in emissions from these plants could equate to a saving of anywhere between half a million and a million tonnes of greenhouse gases per year. That’s like taking up to 200,000 cars off the road each year.

Another avenue we’re exploring is whether we can influence the microbiome (that is, the gut bacteria) of pasture-fed cattle from a young age. We hope this will also reduce methane emissions. This research is still in its early phase. But the idea is to give cattle compounds from a young age to realign the rumen microbiome to produce less methane. The theory is that once the microbiome is altered, the change to low methane digestion will persist. Hopefully for the lifetime of the animal.

The research projects are all based at our Lansdown Research Station, south of Townsville.


  1. I wonder if the meat and the milk will taste noticeably compared to that produced using other feeds? I discovered a couple of years ago, to my surprise, that I can taste the difference between milk produced by different farmers but sold by the same milk producer. I actually called the producer to comment on this as the milk tasted fine on its own to me but had a much different character when added to coffee (I couldn’t use it). They told me that they had switched to a different farmer while the original farmer was resting (or something they do to comply with organic certification) his cows. This led to a bit of digging through the scientific literature on the relationship between milk quality (fat content, etc) on cattle breed and the type of feed. It was fascinating to learn that it can be demonstrated scientifically that we are what we eat to some extent.

  2. Intake of legumes eg Clover is a big mistake ,at certain times of the year Clover bloats the intestinal track and blows up the stomach causeing death within the hour.(How do I know ),had to De-Bloat a cow by punchering the stomach with a triblade device for such.. Mixed grasses with an oil element in the seeds would reverse the process. Without problem exasperating in the first place *
    For your reference consult NZ gvt who started a campaign ten years ago on this very problem.
    Prior use of olive and other oils. 1960s.
    * Bio-active enzymes between different grasses, properly activated should eat one another without fermentation or gasseous byproduct if properly regulated with overlap either way not adding to undesirables.

  3. Are CSIRO looking at its implemenation within the dairy industry? Cows go to be milked twice a day & are also fed in the milking sheds.

  4. I do hope the Green Radicals can swallow this emerging technology. It also highlights the great value the CSIRO contributes to Australia and the world through outstanding research.

  5. If the algae is suitable, it would be interesting to team up algal farms with fish farms as a source of nutrient, assuming they both had the same temperature range. That may help to reduce the incidence of excess nutrient near fish farms.

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