Feeding grazing cattle seaweed cuts methane emissions by almost 40% Findings offer solution for more climate-friendly cattle farming20 January 2025 20 January 2025 3 minute read 3 minute read By: By: University of California-Davis North AmericaSeaweed is once again showing promise for making cattle farming more sustainable. This is the first study to test seaweed on grazing beef cattle in the world. It follows previous studies that showed seaweed cut methane emissions 82% in feedlot cattle and over 50% in dairy cows. Overhead view of the machines that dispense the seaweed supplement and measure the grazing cattle's methane emissions. Grazing cattle also produce more methane than feedlot cattle or dairy cows because they eat more fiber from grass.