Interpretable machine learning for yak milk feeding pattern discrimination: Integrating XGBoost with multidimensional...

Accurately identifying grazing (GZ) and supplementary feeding (SF) patterns in yak milk is important for product authentication; however, current methodologies are often expensive and time consuming. In this study, we examined 523 milk samples of lactating yaks at four stages of SF and tested 21 machine learning algorithms to develop a rapid and cost-effective classification method using routine compositional parameters. Ensemble learning techniques performed better than others, with XGBoost having the best accuracy (92%) and AUC (0.94). Multidimensional interpretability analyses, including SHAP, PDP, and ICE, identified fat content (27.8%) and lactose (23.1%) as the most important discriminators, along with biologically meaningful interactions, such as between fat, lactose, and freezing point. This interpretable framework provides a practical, low-cost method for milk authentication of yaks using ordinary dairy analyzers, providing a methodological foundation for the establishment of standardized GZ certification systems in milk production from yaks.