Abstract
The abundances of low-molecular-weight metabolites in milk have been known to change during the lactation stage, and this is of relevance to the milk nutritional or processing properties. Metabolomics was used to investigate changes in 46 milk samples from 19 Jersey cows. Metabolites were measured using both nuclear magnetic resonance and mass spectrometry based methods. Metabolites exhibiting change were identified with the aid of multivariate and univariate data analysis. The changing metabolites included amino acids and derivatives (taurine, purine, indoleacetic acid, aminoadipic acid), organic acids (uric acid, hippuric acid, citric acid), carbohydrates (N-acetyl-D-glucosamine, galactose-1-phosphate), vitamins (choline and pantothenic acid), nucleic acid-related compounds (cytosine, uracil and methylguanine) and fatty acids (lauric acid). This research not only provides a full understanding of the milk metabolomic changes due to the cow lactation stage but also can be used as the foundation for marker selection for further studies utilising milk metabolomics. (C) 2020 Elsevier Ltd. All rights reserved.