Monitoring the occurrence of subclinical ketosis with a hand-held ketone measuring device in Hungarian dairy herds

The authors have evaluated a new cow-side test in Hungarian dairy herds. With these measurements the occurrence of subclinical ketosis was tested. Twenty-nine dairy farms participated in the study, with a number of 10-12 animals on each farms. All samplings were carried out from day 7 prior to calving till day 14 after calving. 294 animals were sampled in the study by taking blood sample from the coccygeal vein and the level of the beta hydroxy butyrate (BHB) was measured in the peripheral blood. The measurements were carried out with a portable hand held device (Precision Xtra, Abbot Laboratories). The BHB concentrations measured at the farm showed a strong and significant correlation with the samples evaluated in the laboratory before and after freezing (r>0.92, P<0.001). 12.9% of the animals showed elevated levels of BHB (threshold 1.4 mmol/l), and 27.5% of the herds were affected. When setting up a lower threshold (0.85 mmol/l), 24.8% of the animals and 55.2% of the herds were affected. Approximately 5%of the examined animals showed higher than 3.0 mmol/L BHB level indicating clinical ketosis. The pathological history of these animals did not show any sign of metabolic disease, therefore the medical treatment of these animals was necessary. There was an elevation in the level of BHB in the over conditioned cows, however the animals with lower body condition scores (<3.0-3.5) also had a higher BHB concentration (OR=7.5, P<0.001). Parity also increased the percentage of elevated concentrations, after 3 or more calvings the odds of hyperketonaemic cows was double (OR=2.3, P=0.023). Different clinical diseases (mainly puerperal metritis and retained foetal membranes) also increased the risk of subclinical ketosis (OR=2.5, P=0.014). At the time of the study 30 animals had more than one clinical disease, 23 cows had two, 5 cows had three, 2 cows had four different clinical diseases. Based on these results the authors advise the use of hand-held device in the field.