The relationship between concentrations of non-esterified fatty acids and β-hydroxybutyric acid in transition dairy cows

Both non-esterified fatty acids (NEFA) and β-hydroxybutyric acid (BHBA) concentrations have been used as cow and herd-level markers of negative energy balance during the transition period of dairy cows to monitor disease risk and reproductive and milking performance. Prior evidence based on cross-sectional data suggests that the NEFA and BHBA are not well correlated. The objective of this study was to describe the correlation between NEFA and BHBA concentrations of dairy cows in the peripartum period. We hypothesized that accounting for possible lag times between elevation of NEFA and BHBA by using longitudinal data could improve their relationship.