A sampling method for differentiating breath and ruminal exhaled volatile organic compounds in dairy cows using methane as a marker
M.A. Barrientos-Blanco, U. Arshad, S. Giannoukos, M.Z. Islam, C. Kunz, R. Peng, S.E. Räisänen, R. Zenobi, M. Niu
Abstract
Separating Breath from Eructation: Advancing SESI-Based Breathomics in Dairy Cows
This study establishes a validated sampling method to distinguish true breath (BR) from ruminal eructation (RE) in dairy cows—an essential step for applying breathomics in ruminant metabolic research. Using a CH₄-based threshold and the GreenFeed system, researchers collected BR and RE samples from Holstein cows and analyzed them via SESI-HRMS and GC. CH₄ levels were 80% lower in BR, confirming successful separation. SESI-MS detected hundreds of VOC features, with distinct profiles between BR and RE. RE was enriched in VFAs like acetate and butyrate, while BR showed unique endogenous signals. This approach unlocks non-invasive, real-time breath metabolomics for metabolic phenotyping in ruminants, overcoming a long-standing barrier in the field.