Methane Emissions Mitigation in Pasture-Based Dairy Systems Using Macroalgae Asparagopsis taxiformis Supplements

Advances in Agriculture and Agricultural Sciences | Vol. 12, No. 5, May 2026 | pp. 84–89

DOI: 10.46882/2026.AAAS.120502

Research Article

Title: Methane Emissions Mitigation in Pasture-Based Dairy Systems Using Macroalgae Asparagopsis taxiformis Supplements

Names of Authors: Walsh, M. J.¹, O'Neill, H. C.¹, and Smith, R. E.²

Authors’ Affiliations: ¹Animal and Grassland Research and Innovation Centre, Teagasc, Moorepark, Ireland. ²School of Biological Sciences, Queen's University Belfast, Belfast, UK.

Abstract: Enteric methane emissions from ruminant production setups represent a significant driver of national greenhouse gas inventories. This research tracked the methane reduction capacity of supplementing grazing dairy cows with low doses of the marine macroalgae Asparagopsis taxiformis. Thirty lactating Holstein cows were grouped into a randomized design, receiving either 0%, 0.25%, or 0.50% inclusions of macroalgae based on total organic matter intake parameters over an 8-week monitoring block. Enteric outputs were tracked via open-circuit respiration systems during milking. Supplementation at the 0.50% configuration reduced absolute daily methane emissions by 62.4% relative to control groups without changing dry matter intake speeds or pasture consumption rates. Bromoform residue assessments in milk and meat tissue samples fell below the limit of quantification, showing high safety compliance. Milk yields and total milk fat percentages remained stable across all groups. The results show that low-dose macroalgae inclusions can lower climate footprints for pasture-based livestock systems without compromising commercial output metrics.

Keywords: Ruminant livestock; Enteric fermentation; Bromoform residues; Climate mitigation; Algal biomass; Dairy production.

Manuscript Timeline: Received January 12, 2026; Revised March 08, 2026; Accepted April 12, 2026; Published May 24, 2026.

Citation: Walsh, M. J., O'Neill, H. C., and Smith, R. E. (2026). Methane Emissions Mitigation in Pasture-Based Dairy Systems Using Macroalgae Asparagopsis taxiformis Supplements. Advances in Agriculture and Agricultural Sciences, 12(5), pp. 84–89.

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