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Asparagopsis feedlot feeding trial

Did you know methane production from grainfed cattle can be reduced by 98% when supplementing their diets with red seaweed?

Project start date: 01 November 2015
Project end date: 01 May 2018
Publication date: 11 March 2020
Project status: Completed
Livestock species: Grainfed cattle
Relevant regions: National
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There is a global initiative to decrease methane emissions and increase productivity of cattle to benefit the environment, food production and industry profitability. Previous research has shown that Asparagopsis (red seaweed) as a feed additive can reduce ruminants' methane production.

This project tested Asparagopsis for its capability to reduce methane emissions and improve productivity in Brangus steers.

Steers that ate Asparagopsis produced up to 98% less methane, with no negative effects on the quality of beef produced. There was also a preliminary indication of weight gain improvements of 42–53%, though this needs to be confirmed with further research.


This project assessed the impact on methane production by using Asparagopsis as a supplement in Australian cattle feedlots. This was assessed by measuring animal productivity, carcase characteristics, eating quality and chemical residues in the beef.

Key findings

  • The amount of Asparagopsis required to eliminate methane was surprisingly low. Supplementing feed with 0.05%, 0.10%, and 0.20% Asparagopsis reduced methane production by 9%, 38% and 98%, respectively.
  • Hot standard carcase weight, dressing percentage and meat eating quality were not affected by Asparagopsis intake.
  • The bioactive from Asparagopsis, bromoform, can be unsafe if consumed in high amounts, but there was no trace detectable in the meat, kidney or fat tissues of the steers.
  • There was no change in feed intake across the different levels of Asparagopsis inclusions into the feed. However, at the inclusion levels of 0.10% and 0.20%, there was an indication of weight gain improvement of 53% and 42%, respectively. Given the small sample size of animals, this needs to be confirmed with further work.

Benefits to industry

If feeding cattle Asparagopsis proves feasible, the industry will benefit by improving its environmental footprint, profitability (through improved weight gains) and social licence to operate.

Feeding cattle Asparagopsis would also increase the red meat industry's capability to achieve MLA's commitment of carbon neutrality by 2030 (CN30).

MLA action

MLA has established an agreement with CSIRO to commercialise Asparagopsis. This process will involve further research to identify appropriate inclusion levels in variable feed formulations and confirm the productivity improvements, plus develop a supply of Asparagopsis and market supply chain.

Future research

  • Cattle response to Asparagopsis is expected to change with feed type, so further investigation is required to identify the recommended amount of supplement for different feed formulations.
  • Further studies are required to confirm how Asparagopsis can be applied to improve productivity in commercial feedlots through increases in weight gain.
  • Due diligence with respect to bromoform is required, particularly for cattle on longer term feeding programs.

More information

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Primary researcher: CSIRO