Mask for individual sampling of tidal and ruminal gas contaminated breath in dairy cows

Standardized breath sampling in dairy cows is helpful for health monitoring and emission control. Yet, controlled measurements of and discrimination between tidal and ruminal gas contaminated breath are challenging. Here, we introduce a sampler designed to collect exhaled breath reproducibly from dairy cows. The system integrates pressure regulators and valves to enable normal breathing patterns. Combined real-time monitoring of CH4 and CO2 concentrations facilitates distinction and separate collection of tidal versus ruminal gas contaminated breath into sampling bags. A comprehensive system-level validation is performed, including sampler inertness testing toward various volatile organic compounds (VOCs). Also sample stability over 14 days is exemplarily assessed with Supel™-Inert Multi-Layer Foil bags across different concentration ranges. The sampling mask is validated on 31 dairy cows (total 1187 samples) using proton-transfer-reaction time-of-flight mass spectrometry to quantify physiologically relevant VOCs, including acetone, ethanol, isoprene, acetic acid, propionic acid and butanoic acid. Overall, this sampler provides a robust, extendable solution for livestock breath sampling and characterization.