Wieland Matthias, Geary Christina Marie, Gioia Gloria, Case Kerry Lynn, Moroni Paolo, Sipka Anja
Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY 14853, USA.
Dipartimento di Medicina Veterinaria, Università degli Studi di Milano, Via dell'Università, 6, 26900 Lodi, Italy.
Animals (Basel). 2021 Jun 23;11(7):1860. doi: 10.3390/ani11071860.
The primary objective of our study was to assess the ability of a vacuum recorder to detect the presence of bimodal milk flow curves in dairy cows compared with a portable milk flow meter. In a cross-sectional study, 241 individual cow milking observations were analyzed. We simultaneously collected (1) individual cow vacuum events during milking using portable vacuum recorders, and (2) individual cow milk flow curves by attaching a portable milk flow meter to the same milking unit. Presence of bimodality was assessed with the vacuum recorder visually (BIM) and with the gold standard method of a milk flow meter through automatic detection (BIM). Kappa statistics revealed moderate agreement between BIM and BIM [κ, 95% confidence intervals (95% CI) = 0.59 (0.46-0.71)]. Diagnostic test statistics for BIM for detection of bimodality indicated moderate performance for sensitivity [0.65 (0.52-0.76)] and positive predictive value [0.71 (0.58-0.82)] and high values for specificity [0.92 (0.87-0.95)] and negative predictive value [0.93 (0.84-0.93)]. We conclude that milking vacuum dynamics are a suitable measure to assess bimodal milk flow curves in dairy cows.
我们研究的主要目的是评估与便携式奶流量计相比，真空记录仪检测奶牛双峰奶流曲线的能力。在一项横断面研究中，分析了241头奶牛的个体挤奶观测数据。我们同时收集了：(1) 使用便携式真空记录仪在挤奶过程中记录的个体奶牛真空事件，以及(2) 通过将便携式奶流量计连接到同一挤奶单元获得的个体奶牛奶流曲线。通过真空记录仪以视觉方式评估双峰性（BIM），并通过奶流量计的金标准方法进行自动检测（BIM）。Kappa统计显示BIM和BIM之间存在中度一致性 [κ，95% 置信区间（95% CI）= 0.59（0.46 - 0.71）]。用于检测双峰性的BIM诊断测试统计显示，其敏感性 [0.65（0.52 - 0.76）] 和阳性预测值 [0.71（0.58 - 0.82）] 表现中等，但特异性 [0.92（0.87 - 0.95）] 和阴性预测值 [0.93（0.84 - 0.93）] 较高。我们得出结论，挤奶真空动态是评估奶牛双峰奶流曲线的合适指标。
