Study Examines Practicality of Methane-Reducing Seaweed for Grazing Cattle
Project at UC ANR center in Yuba County probes additive effectiveness on rangelands
Previous studies have shown that adding red seaweed (Asparagopsis taxiformis) to beef cattle rations could reduce methane – a potent greenhouse gas – produced by the animals by up to 90%.
But those results were in controlled settings – not wide-open rangelands.
“The challenge now is finding a reliable method of delivering the seaweed product to cattle grazing on pasture,” said Andrea Warner, a University of California Cooperative Extension livestock and natural resources advisor for Sutter, Yuba, Placer and Nevada counties.
“Cattle in feedlots or dairies are being fed a total mixed ration every day and they’re in a more controlled environment,” Warner explained, “whereas out here [on rangelands] we could have cattle grazing on several hundred acres of pasture.”
Andrea Warner, UCCE livestock and natural resources advisor for Sutter, Yuba, Placer and Nevada counties, is actively involved in the seaweed additive study. Photo by Evett Kilmartin
Scientists added red seaweed to a salt-based mineral supplement mix, which they put in “free choice” feeders – covered metal troughs – in the pasture. When they tried to measure results, they discovered two things. One, actual consumption of the supplement was inconsistent, with seemingly less efficacy in decreasing methane output. And two, their conclusions were limited by significant shortcomings in their data.
“Our results really said that we needed better capabilities to make measurements,” said Sheila Barry, UCCE livestock and natural resources advisor for the San Francisco Bay Area.
Barry is the first author of a study published last year, funded by the Russell L. Rustici Rangeland and Cattle Research Endowment, UC Davis. The authors concluded that additional research – with improved equipment and methods – was needed to better understand how seaweed additives could realistically be incorporated into grazing systems.
That’s why Barry, Warner and their collaborators are back with a new project at UC ANR’s Sierra Foothill Research and Extension Center in Browns Valley, Yuba County. This study is funded by the California Department of Food and Agriculture’s Livestock Enteric Methane Emission Reduction Research Program.
The first phase of the project is running “palatability trials,” to gauge whether the addition of seaweed affects the cows’ consumption of the mineral. That will help the scientists determine optimal mineral mixtures. Subsequent phases will assess consistency of the cows’ consumption, verify any reductions in methane and measure impacts on livestock performance (i.e., weight change and body condition).