July 17, 2023

 

Australian trial of seaweed cattle feed shows lower methane reductions than expected

A trial of a seaweed supplement Asparagopsis to 40 wagyu cattle in an Australian feedlot for 300 days conducted in Australia recorded much lower reductions in greenhouse gas compared to previous studies, The Guardian reported.

 

The trial resulted in a 28% decrease in methane production, significantly lower than the widely promoted claims of over 80% reduction, with some studies even suggesting reductions as high as 96%.

 

Methane emissions from cattle, known as enteric emissions, contribute significantly to greenhouse gas emissions. While methane is about 80 times more potent than CO2 in terms of warming the planet, cutting methane is seen as a crucial step in mitigating global heating.

 

But the trial conducted by Meat and Livestock Australia (MLA) revealed that the animals given the seaweed supplement ate less food and weighed 15kg less by the time of slaughter.

 

Dr Fran Cowley, the livestock scientist who led the trial at the University of New England, acknowledged that more research is needed to understand why the wagyu cattle in this trial did not exhibit the same level of emissions reductions as seen in other experiments. The open-air measurement system used in this trial could have influenced the results, as other experiments conducted in similar conditions showed higher methane reductions over shorter timeframes.

 

Despite the lower results in this trial, Cowley believes that cuts of 90% are still achievable in the real world, but economic factors must be considered by commercial producers when factoring in the cost of the supplement.

 

The seaweed supplement, mixed in canola oil and added to the animals' feed, was administered at slightly lower concentrations in this trial compared to previous experiments that demonstrated higher methane reductions. The reasons behind the animals eating less food and gaining weight more slowly while on the supplement remain unclear. Additionally, accounting for the extra days the animals took to reach the same weight theoretically reduced the emissions savings from 28% to 19%, as the animals emitted methane for a longer period.

 

Dr Rob Kinley, chief scientist at FutureFeed, the Australian company holding the intellectual property for the use of Asparagopsis as a livestock feed supplement, said that other trials will deliver higher methane reductions.

 

He said that the supplement was able to consistently reduce methane emissions by just under 30% for 275 days, which is still significant progress.

 

The Australian government, along with industry players like the Australian Agricultural Company (AACo), continues to fund research programmes to test various methane-reducing livestock supplements, including red seaweed.

 

While the recent trial fell short of expectations, AACo's CEO David Harris emphasised the importance of persevering in finding solutions to reduce enteric methane emissions, recognizing the significant reduction achieved by the trial.

 

The findings from each research project contribute to the overall understanding of products incorporating Asparagopsis and identify further questions that need to be addressed, according to an MLA spokesperson.

 

-      The Guardian