Method: GreenDA – A user-friendly tool for processing and exploring large-scale GreenFeed® data

The GreenFeed® is used worldwide for individual methane ( CH 4 ) emission measurement without restricting animal behaviour. It enables a large number of spot gas samples per animal and can simultaneously measure emissions from up to 20–25 animals. However, robust analytical tools that can easily handle large volumes of data generated in real time by this system remain limited. To address this shortcoming, we developed an application that provides user-friendly functionalities (i.e., simple button-based operations) designed for inexperienced users in data analysis programming and large dataset management. This software includes useful features for processing data (e.g., outlier elimination), basic descriptive statistics and calculations (e.g., repeatability; REP ), as well as data visualisation and reporting at different levels (i.e., herd, animal, treatment) and different time intervals (e.g., hour, day). These descriptive summaries provide valuable insights into which subsequent statistical analyses may be appropriate. To illustrate the functionality of GreenDA, we utilised data collected from 53 cows over a 105-day period using two GreenFeed®. Animals were assigned to a 2 × 2 factorial design with two factors, including diet (Treatment 1) and breed (Treatment 2). After preprocessing the dataset using the default settings of GreenDA, 124 out of 19 749 records were identified as outliers and subsequently removed. The CH 4 emission data followed a normal distribution, and REP reached a plateau in 7 days per subgroup (REP = 0.62). The CH 4 emission kinetics closely mirrored the intake pattern, which was not affected by treatment. The total number of visits peaked at 0100 h and reached its lowest point at 0200 h; however, this daily pattern differed between treatments. All of these analyses were conducted according to the analysis guidelines provided with GreenDA. GreenDA not only analyses large data sets collected by the GreenFeed® but also provides the scientific community with comprehensive guidance for optimising analyses.