[Validation of a cow-side blood test for beta-hydroxybutyrate concentration in dairy cows].

Objective: Clinical ketosis is common during the dairy cows' transition period and is responsible for considerable economic loss. Early identification of cows with subclinical ketosis is the first step for maintaining the health and productivity of dairy cows. The goals of the study were two-fold: The first was to examine the usefulness of a mobile test device as a cow-side test; and the second was to compare BHB concentrations measured by the ketometer using capillary blood and blood collected from the coccygeal vessels with values determined by a reference method in the laboratory using jugular blood.
Material and Methods: Blood samples were collected from a jugular vein or the coccygeal vessels in 81 dairy cows at 7 time points (14 and 7 days pre-partum and 7, 14, 21, 28, and 42 days post-partum) for kinetic enzymatic measurement of BHB concentration in the laboratory. Blood samples were concurrently collected from the coccygeal vessels or by pricking the vulvar lip at the transition of the skin to the mucosa (capillary blood) to determine BHB concentration using the WellionVet BELUA ketometer (MED TRUST GmbH, Marz, Austria).
Results: Initial errors in operating the ketometer were quickly eliminated with experience. BHB concentrations of jugular blood measured in the laboratory were 0.07 mmol/l lower than those measured in coccygeal blood. The mean BHB concentration measured in coccygeal and capillary blood using the WellionVet BELUA ketometer did not significantly differ but were 0.13 and 0.12 mmol/l respectively, lower than the mean jugular vein concentrations measured in the laboratory.
Conclusion: The WellionVet BELUA ketometer is useful for determination of BHB concentration in cows provided that the manufacturer's specifications are followed. Capillary blood is best collected at the transition from the vulvar skin to its mucosa. The device generates rapid results that correlate well with BHB concentrations determined in the laboratory and with the results obtained from different blood collection sites. It is ideally suited for monitoring dairy cows for subclinical ketosis using capillary or coccygeal blood.
Competing Interests: Die Autoren bestätigen, dass kein Interessenkonflikt besteht.
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