[Determination of beta-hydroxybutyrate in milk using test strips: a new aid for the diagnosis of subclinical and clinical ketosis in the cow].

In order to evaluate a dipstick test for the semi-quantitative determination of beta-hydroxybutyrate (BHB) in milk, we determined the BHB content in milk samples of healthy and ketotic high yielding dairy cows with the dipsticks. BHB was analysed on an analyser in 39 of these milk samples as well as in 88 blood samples which were drawn when milk samples were obtained. There was a strong correlation between milk BHB values which were determined with the two methods (r = 0.92; BHB quantitative = -9.9 + 1.25 x BHB dipstick value). Although BHB concentration in plasma is much higher than in milk, the correlation between plasma BHB, determined on an analyser, and the dipstick test results in the corresponding milk samples was also quite strong (r = 0.84; plasma BHB in mmol/l = 0.23 + 0.009 x milk BHB in mumol/l, determined with dipsticks). The dipstick test is suitable for the diagnosis of clinical ketosis and for monitoring the energy status of high yielding dairy cows.