Experimental and experiential recommendations for using the GreenFeed systems to measure gas flux in grazing and confined cattle.

Improving ruminant production efficiency is contingent on accurately measuring gas fluxes from individual animals in grazing and confined feeding environments The GreenFeed system (GFS) has been increasingly utilized by researchers to measure gas flux of ruminants in their production environment. However, there are wide inconsistencies in methodologies from laboratory-to-laboratory. The objective of this manuscript is to provide standardized recommendations for measuring individual animal gas fluxes of methane, carbon dioxide, oxygen, and hydrogen by the GFS, which are based on experiential and experimental evidence. The method includes:•GFS management: Setup, maintenance, and calibration of sensors•Animal Recommendations: Number of animals to sample, training on use of the system, and bait feeds - including type, composition, and mass. Further, we address operational considerations of using the GFS in extensive grazing environments and confined feeding operations.•Data recommendations: pre-processing data, data cleaning, handling outliers, approaches for estimating individual animal gas fluxes, and uses of application performance interfaces in conjunction with R for statistical analyses.Increasing standardization in GFS management across experiments and laboratory groups is greatly needed. We hope that these recommendations based on our collective experience and experimental evidence will aid in the standardization of GFS methodologies.