Two trials were conducted to examine factors
potentially influencing the measurement of blood
β-hydroxybutyric acid (BHBA) in dairy cows. The ob-
jective of the first trial was to study effects of sampling
time on BHBA concentration in continuously fed dairy
cows. Furthermore, we determined test characteristics
of a single BHBA measurement at a random time of
the day to diagnose subclinical ketosis considering com-
monly used cut-points (1.2 and 1.4 mmol/L).