Association of subclinical hypocalcemia dynamics with dry matter intake, milk yield, and blood minerals during the periparturient period

Subclinical hypocalcemia (SCH) affects many high-producing dairy cows in the postpartum period. Recent work has shown that experiencing prolonged or delayed SCH are at increased risk for disease and produce less milk than a transient reduction normal concentrations of plasma Ca following parturition. Our objective was to determine association between different dynamics with pre- dry matter intake (DMI), yield, blood mineral concentrations. Data were retrospectively collected from multiparous Holstein (n = 78), classified into 1 4 groups based on mean total (tCa) d (DIM): normocalcemic (NC; [tCa] >1.95 mmol/L DIM >2.2 DIM, n 28); (tSCH; ≤1.95 27); (dSCH; ≤2.2 6); persistent (pSCH; mmol 17). Linear mixed models created analyze change DMI, over time as well differences groups. Prepartum similar groups, but NC tSCH consumed more feed pSCH dSCH during first 3 wk lactation. The produced other 6 Postpartum tCa Mg highest lowest cows. results suggest high level DMI by period supported an appropriate homeostatic response demands lactation, allowing higher yield compared their counterparts episodes SCH.