The MetaBó-Bainne Study – characterisation of the milk metabolome from a seasonal pasture-based dairy system using 1H-NMR spectroscopy

This study aims to characterise the milk metabolome from a seasonal pasture-based dairy system using 1H-NMR spectroscopy. Over 41 weeks, ten dairy farms were visited weekly for the collection of raw bulk tank milk samples (n = 410) and three commercial pasteurised skimmed milks were also purchased weekly (n = 123). In total, 38 milk metabolites were quantified, 30 of which exhibited significant seasonal variation. Multivariate analysis identified several key compounds associated with seasonal metabolic changes. Winter-Feb milk, corresponding to early-lactation period, was enriched in ketone bodies, O-phosphocholine, creatinine, and glucose-1-phosphate, reflecting increased metabolic stress and negative energy balance following parturition. In contrast, autumn milk, corresponding to late-lactation, contained higher concentrations of choline and urea, indicative of improved energy status but reduced nitrogen use efficiency. These findings highlight the potential of milk metabolomics as a valuable tool for monitoring physiological status and guiding interventions to enhance sustainability in dairy systems.