Macmillan K, López Helguera I, Behrouzi A, Gobikrushanth M, Hoff B, Colazo M G
Livestock Research Section, Alberta Agriculture and Forestry, Edmonton T6H 5T6, Canada.
Department of Animal Production, Agrotecnio Center, University of Lleida, Lleida 25198, Spain.
Res Vet Sci. 2017 Dec;115:327-331. doi: 10.1016/j.rvsc.2017.06.019. Epub 2017 Jun 27.
The objective of this study was to evaluate the use of a cow-side device (FreeStyle Precision Neo™) to diagnose ketosis and hypoglycemia based on measures of blood β-hydroxybutyrate (BHBA) and glucose. Eleven commercial dairy farms were visited and blood samples were taken from Holstein cows between 2 and 14days in milk, yielding 441 samples for BHBA analysis and 308 samples for glucose analysis. Concentrations of BHBA and glucose were measured in two ways, 1) using the cow-side device with whole blood immediately after sampling and 2) serum samples analyzed with a standard laboratory assay (Animal Health Laboratory, University of Guelph, Canada). The accuracy of the device was determined by comparing the results to the laboratory method as well as the ability to diagnose ketosis (BHBA ≥1.2mmol/L) and hypoglycemia (glucose <2.5mmol/L). The concordance correlation coefficient (CCC), Bland-Altman plot and Kappa coefficient were calculated to evaluate agreement between the 2 methods using SAS (version 9.3). The CCC was 0.92 for BHBA and 0.56 for glucose measurements. The 95% confidence intervals of the Bland-Altman plot encompassed 97% and 95% of the mean difference between methods for BHBA and glucose measurements, respectively. The Kappa coefficients were 0.78 for BHBA and 0.23 for glucose measurements. These results indicate that the cow-side device is accurate for rapid measurement of blood BHBA and diagnosis of ketosis on farms but is not accurate for measurement of blood glucose concentrations and diagnosis of hypoglycemia.
本研究的目的是评估一种奶牛现场检测设备（FreeStyle Precision Neo™）基于血液β-羟基丁酸（BHBA）和葡萄糖检测来诊断酮病和低血糖症的效用。研究人员走访了11个商业化奶牛场，采集了产奶2至14天的荷斯坦奶牛的血样，共获得441份用于BHBA分析的样本和308份用于葡萄糖分析的样本。BHBA和葡萄糖的浓度通过两种方式进行测量：1）采样后立即使用奶牛现场检测设备对全血进行检测；2）用标准实验室检测方法（加拿大圭尔夫大学动物健康实验室）对血清样本进行分析。通过将检测结果与实验室方法进行比较以及诊断酮病（BHBA≥1.2mmol/L）和低血糖症（葡萄糖<2.5mmol/L）的能力来确定该设备的准确性。使用SAS（版本9.3）计算一致性相关系数（CCC）、Bland-Altman图和Kappa系数，以评估两种方法之间的一致性。BHBA测量的CCC为0.92，葡萄糖测量的CCC为0.56。Bland-Altman图的95%置信区间分别涵盖了BHBA和葡萄糖测量方法之间平均差异的97%和95%。BHBA测量的Kappa系数为0.78，葡萄糖测量的Kappa系数为0.23。这些结果表明，该奶牛现场检测设备在农场中用于快速测量血液BHBA和诊断酮病是准确的，但在测量血糖浓度和诊断低血糖症方面不准确。
