A calcium-associated serum metabolomic fingerprint in anorectic dairy cows.

Anorexia in dairy cows arises from diverse causes, including metabolic disorders with and without hypocalcemia. We analyzed the serum metabolites of 21 clinical anorectic cows using two-dimensional gas chromatography coupled with mass spectrometry to determine if the serum metabolome varies across the continuum of total calcium (tCa) in anorectic cows. We tested associations between tCa and the 1,645 detected metabolites by using rank-based partial Spearman correlations, adjusting for age and days in milk. A composite fingerprint derived from the 24 metabolites traced tCa (ρ= -0.773, P=0.0004). A metabolomic fingerprint associated with serum calcium levels could provide new insights into the transition from threshold thinking to continuous exploratory physiology in dairy cows.