Ruminants

Large animal models, including ruminants, provide a suitable basis for biomedical research evaluating volatile organic compounds (VOCs) as indicators of physiological conditions or biomarkers of disease. VOC analysis in ruminants spans in vitro headspace analysis of cellular and bacterial emissions and classical breath analysis, and includes even herd monitoring in the stable air. To ensure high quality breath samples from ruminants, controlled collection of alveolar gas is mandatory, as is the elimination of confounding volatiles derived from eructation episodes. One of the most important sources of biological variability in healthy ruminants is changes in metabolism due to the transition from milk-depending young animals to ruminating herbivores and the corresponding shifts in the microbiome of the intestinal tract. Careful methodological standardization and well-founded evaluation of physiological variability is indispensable for translating VOC research toward applied metabolic monitoring or detection of diseases, such as mycobacterial infections in the field.