Australian study shows seaweed cuts cow methane without feed or milk impact

By Jane Byrne

- Last updated on GMT

Holstein cattle dairy cow herd graze on farm pasture in Kangaroo Valley, New South Wales, Australia © GettyImages/JohnnyGrieg
Holstein cattle dairy cow herd graze on farm pasture in Kangaroo Valley, New South Wales, Australia © GettyImages/JohnnyGrieg

Related tags Dairy methane emissions seaweed

Australian researchers have shown that both liquid and pelleted forms of the red seaweed Asparagopsis significantly reduce methane emissions in dairy cows, without affecting milk safety.

Conducted at Agriculture Victoria's Ellinbank SmartFarm and funded by Agriculture Victoria, GrainCorp Limited, and the Department of Agriculture, Fisheries and Forestry, their study highlights a promising strategy for sustainable livestock farming.

“With a methane-suppressing effect of more than 20%, Asparagopsis is the most promising of many feeding strategies we have investigated,” senior research scientist at Agriculture Victoria, Richard Williams, tells FeedNavigator.

Red seaweeds such as Asparagopsis armata and Asparagopsis taxiformis have been widely reported to have antimethanogenic effects when fed to dairy cows.

Though Williams noted the need for further research to enhance the effectiveness and delivery methods of red seaweed-based methane blocking feeding strategies. 

The study​ involved 40 lactating Holstein-Friesian cows, which were divided into four groups and given different dietary treatments twice daily for 34 days. The treatments included basic diets with and without seaweed supplements, provided either as a liquid or pellet. The cows' primary diet included vetch hay and a grain mix.

Key findings revealed a 20% reduction in methane emissions for cows fed with both liquid and pelleted seaweed supplements. Critically, while the seaweed increased bromoform levels in milk, these remained far below the safety threshold for human consumption.

This indicates that the seaweed supplements effectively reduce methane emissions and that the milk from these cows is safe to drink, conclude the authors.

In an editorial webinar​ on July 2 on FeedNavigator, we investigate how management systems, diets, and feed additives influence the production of enteric methane emissions in beef and dairy cattle and how cross-industry collaborative is advancing efforts in this regard. We also look at the role genetics and measurements can play.

Delivery systems

The study also explored new delivery systems, such as Asparagopsis steeped in edible oils, which have proven equally effective in reducing methane emissions.

Most research has focused on feeding livestock a total mixed ration (TMR) with Asparagopsis seaweed in every bite, say the authors. However, there's a need to find suitable ways to deliver these supplements in different farming systems where feeding isn't as frequent, they add.

Traditionally, Asparagopsis is freeze-dried and mixed into TMR with strong flavors like molasses to mask its taste. New formulations are being developed for easier on-farm use. One promising method involves soaking Asparagopsis in edible oils, such as canola oil, to extract and stabilize its bromoform content.

Researchers concluded that both liquid and pelleted formulations are effective in reducing methane emissions, with no impact on milk yield or feed intake, and are safe for human consumption. The choice between liquid and pellet supplements can be made based on practicality and farm practices.

Methane from the digestive process of livestock accounts for the majority of Australia’s agricultural emissions, according to government data. 

FutureFeed was formed in August 2020 to commercialise the Asparagopsis based technology developed by Australia’s national science agency CSIRO, together with MLA and James Cook University. FutureFeed is supported by investors such as GrainCorp, Harvest Road Group; Woolworths Group; AGP Sustainable Real Assets; Sparklabs and-Cultiv8 Joint Venture.

FutureFeed has issued licenses​ to seaweed growers which enables the supply of Asparagopsis to the livestock market.  

Government funding 

The Australian government's methane emissions reduction in livestock (MERiL) program​ is designed to support the research and development of methane-reducing livestock feed supplements and forage feeds.

As most of Australia’s livestock graze over large areas and have limited contact with farmers, the MERiL program is also supporting work into the development of technologies to deliver methane-reducing feed supplements and other solutions for pasture-based production.

Study source: Animal Feed Science and Technology 

Title: The effects of feeding liquid or pelleted formulations of Asparagopsis armata to lactating dairy cows on methane production, dry matter intake, milk production and milk composition

Authors: S.R.O. Williams, A.S. O Neachtain, S. Chandra, R.B.S. Burgess, S. Labaf, G. Aylward, P.S. Alvarez-Hess, J.L. Jacobs

DOI: https://doi.org/10.1016/j.anifeedsci.2024.115891

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