Transition cow nutrition and management strategies of dairy herds in the northeastern United States: Part II—Associations of metabolic and inflammation-related analytes with health, milk yield, and reproduction

The objectives were: 1) establish cow-level thresholds for prepartum nonesterified fatty acids (NEFA) and postpartum NEFA, β-hydroxybutyrate (BHB), and haptoglobin (Hp) concentrations associated with negative health events; 2) evaluate cow-level associations between biomarkers and 305-d mature equivalent milk at the 4th test day (ME305) and reproductive performance; and 3) identify herd-alarm levels (proportion of cows sampled above the critical threshold) for biomarkers that are associated with herd-level changes in disorder incidence [displaced abomasum (DA) and clinical ketosis (CK)], reproductive performance, and ME305. In a prospective cohort study, 1,473 cows from 72 farms were enrolled from Northeastern United States. At the cow-level and herd-level, elevated biomarker concentrations were associated with an increased disorder risk and varied performance responses.