An Australian trial on the use of red seaweed to reduce methane emissions from livestock has delivered some positive results in the longest trial to date on cattle.
The trial, which involved feeding the seaweed asparagopsis to feedlot Wagyu cattle over 300 days, delivered a 28% reduction in methane released from the livestock.
Australian Agricultural Company managing director David Harris said they had anticipated a higher methane abatement level, but that a reduction of almost 30% is still significant.
“It helped us understand more about how to apply asparagopsis and what we can consider to improve outcomes in the future,” he said.
Feed refusal was an issue in the trial, something noted in previous reports.
The results appear to add one solution to an evolving mix of methane-reducing options, with Harris acknowledging there is no silver bullet to eliminate methane emissions.
Other important outcomes from the trial include no changes to taste or marbling, and the ability to use asparagopsis oil over a sustained period.
“No one had tested those things in Wagyu previously, but they are important findings especially as a beef company selling a premium product into global markets,” he said.
“Importantly, we also learnt that it’s safe for long-fed cattle like Wagyu to consume over those extended periods.”
One issue raised by the trial was the reduction in liveweight of almost 10%, and the ration type and size required to get the outcomes in Wagyu cattle.
Harris acknowledged a challenge that New Zealand researchers are also facing: how the product can be used in tackling methane reduction in extensive grazing environments. In Australia that includes stations with over a million square kilometres of grazing country.
“Feed additives generally are only one part of the solution. There will be other approaches and technologies that emerge to complement them.”
Fonterra is also engaged in asparagopsis trials in Tasmania on a dairy farm. The trial product is being fed to 1000 cows.
In February Jack Holden, Fonterra’s GM for sustainability, told FoodBev Media there had been no unacceptable residues in milk tested to date, with some recent Australian research suggesting levels of bromoform residue were well below food safety thresholds.
Holden confirmed this week that Fonterra is aware of the latest report and the feed refusal issues. He said Fonterra is taking a conservative approach on the rate of asparagopsis inclusion, to reduce the risk of feed refusal.
“We still have more to learn about using red seaweed, and other possible low-methane innovations. We will be continuing trials into the 2023-24 milking season and will keep building on our early work as well as learning from others.”
Fonterra is also trialling a number of other methane-reducing technologies, including milk culture extracts in its Kowbucha trial product.