Work

Unsupervised clustering identifies candidate metabolic profiles, including an acidotic profile detectable before calving, in periparturient dairy cows

Year: 2026

Type: article

Abstract: The metabolic status of periparturient dairy cows is highly heterogeneous, making it difficult for traditional assessment methods based on a single biomarker to comprehensively reflect systemic metabolic dysregulation. This study aimed to apply unsupervised clustering to identify distinct metabolic phenotypes using integrated blood physiological indicators and to evaluate the prepartum identifiability of metabolically compromised profiles. Venous blood samples were collected from 316 healthy Holstein cows (from - 7 to + 7 days relative to calving) across seven commercial farms in China for blood gas and electrolyte analysis. After data cleaning and variable selection, six key indicators-pH, PCO₂, HCO₃⁻, glucose, potassium, and sodium-were standardized and subjected to K-means clustering. The optimal number of clusters was determined to be three, yielding the following phenotypes: (1) a "metabolically compromised" group characterized by acidosis (low pH), hypercapnia (elevated PCO₂), hypoglycemia, and electrolyte imbalance; (2) a "normoacidemic-hyperkalemic" group with normal acid-base status but persistently elevated potassium; and (3) a "metabolically homeostatic" group exhibiting alkalotic tendencies, higher sodium and glucose levels, and stable electrolyte balance. A substantial proportion of cows already belonged to the metabolically compromised phenotype before calving, and its prevalence peaked during the mid-postpartum period (+ 4 to + 7 d). In unadjusted analyses, cows in this cluster exhibited modestly elevated postpartum β-hydroxybutyrate concentrations (P = 0.001) and significantly reduced milk protein percentage (P < 0.001); however, the BHBA association was not significant after adjusting for farm of origin in a mixed-effects model (P = 0.622), whereas the milk protein association remained robust. These findings indicate that impaired metabolic adaptation in this cluster is more consistently reflected by reduced milk protein than by elevated BHBA. Based on cluster centroids and validated by exploratory ROC analysis, prepartum thresholds for identifying the metabolically compromised profile were proposed: venous pH < 7.25 (AUC = 0.928), PCO₂ > 58.75 mmHg (AUC = 0.956), and glucose < 27.5 mg/dL (AUC = 0.876). Potassium was not retained as a discriminatory threshold because its AUC was only 0.577. These thresholds are exploratory and require validation in independent cohorts. These findings demonstrate that periparturient dairy cows segregate into three distinct metabolic states, and that a metabolically compromised acidotic profile can be identified antepartum. This provides a foundation for early risk stratification; future intervention studies are needed to determine whether targeting this profile improves clinical outcomes.

Source: Tropical Animal Health and Production

DOI: 10.1007/s11250-026-05438-3