Figure 1

Study design. For the examination of acute stress, saliva samples were obtained non-invasively from 200 pigs. Cotton ropes were provided, yielding 63 pooled saliva samples, each from 5 to 10 pigs. Saliva was collected from the same pigs twice: (1) before stressful conditions (n = 31); and (2) after 24 h in stressful conditions (n = 32). Metabolites were extracted and analysed using an ultra-high‐performance liquid chromatography high-resolution mass spectrometer. Raw data was used for data pre-processing, identification of features as metabolites, and data analyses for the identification of altered metabolites and metabolic pathways. Procreate (version 5.2.6) and Adobe Photoshop Creative Cloud (version 23.5.1) were used for the graphics and illustrations.