Byrd M K H, Arneson A G, Soffa D R, Stewart J W, Rhoads M L
Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg 24061.
JDS Commun. 2021 Nov 18;3(1):78-83. doi: 10.3168/jdsc.2021-0147. eCollection 2022 Jan.
If validated for use in dairy cattle, interstitial continuous glucose monitors (CGMs) could be easily implemented, informative tools for research, clinical, and perhaps even on-farm applications. To evaluate their efficacy, 2 experiments were conducted, during which lactating Holstein cows were fit with indwelling jugular catheters, as well as FreeStyle Libre (FSL; Abbott) and Dexcom G6 (DexCom Inc.) CGMs secured either behind their polls, lateral to their ears, or beneath their pin bones on their upper rear legs. During the first experiment, blood (measured with a handheld glucometer) and interstitial glucose measurements were collected from 13 cows every 4 h for 96 h. In the second experiment, the same measurements were collected from 8 cows every 15 min for 6 h. At the mid-point of the sampling period (3 h), cows received a bolus dose of dextrose to facilitate comparisons across a broad range of glucose concentrations. Results from both experiments determined that functional longevity of the sensors was greatest for those sensors secured near the ear. Likewise, interstitial measurements from the ear sensors were most closely correlated with blood glucose concentrations (r = 0.82 and r = 0.71 for FSL ear and Dexcom G6 ear, respectively). Unfortunately, accuracy calculated as absolute relative error was low, at 60.7% or less. As a result of the low accuracy, even though both ear sensors detected an increase in glucose concentrations following the bolus dose, neither produced results exactly matching blood glucose measurements. The results of this work indicate that the FSL and Dexcom G6 CGMs are not currently capable of replacing blood-based glucose measurements.
如果经证实可用于奶牛，组织间连续血糖监测仪（CGM）可能会很容易地得以应用，成为用于研究、临床甚至农场应用的信息工具。为评估其功效，进行了2项实验，在此期间，给泌乳的荷斯坦奶牛植入颈静脉导管，并在其头顶后方、耳朵外侧或后腿上部臀骨下方固定FreeStyle Libre（FSL；雅培公司）和德康G6（德康公司）CGM。在第一项实验中，每4小时从13头奶牛身上采集血液（用手持式血糖仪测量）和组织间葡萄糖测量值，共采集96小时。在第二项实验中，每15分钟从8头奶牛身上采集相同测量值，共采集6小时。在采样期的中点（3小时），给奶牛静脉推注葡萄糖，以利于在广泛的葡萄糖浓度范围内进行比较。两项实验的结果均表明，固定在耳朵附近的传感器功能寿命最长。同样，耳朵传感器的组织间测量值与血糖浓度的相关性最高（FSL耳朵传感器和德康G6耳朵传感器的r值分别为0.82和0.71）。遗憾的是，以绝对相对误差计算的准确性较低，为60.7%或更低。由于准确性较低，尽管两个耳朵传感器在推注葡萄糖后都检测到葡萄糖浓度升高，但两者的结果都与血糖测量值不完全匹配。这项工作的结果表明，目前FSL和德康G6 CGM尚无法替代基于血液的血糖测量。
