Epidemiology of subclinical hypocalcemia in early-lactation Holstein cows

Abstract

Hypocalcemia is one of the most common periparturient abnormalities afflicting dairy cows. The disorder is frequently divided into a clinical (i.e., parturient paresis) and a subclinical state, with the latter receiving much recent research attention. For classification purposes, subclinical hypocalcemia (SCH) should be defined as low blood Ca concentrations that are associated with periparturient health disorders, poorer production and reproduction outcomes, or both, without associated signs of postpartum paresis. Our objective was to characterize the epidemiology of SCH in Holstein cows by assessing the temporal associations of plasma Ca concentrations in the first 4 days-in-milk (DIM) with the risk of cows being diagnosed with metritis/and or displaced abomasum in the first 60 DIM and milk production across the first 15 wk of lactation.