Pohl A, Heuwieser W, Burfeind O
Clinic of Animal Reproduction, Faculty of Veterinary Medicine, Freie Universität Berlin, Königsweg 65, 14163 Berlin, Germany.
Clinic of Animal Reproduction, Faculty of Veterinary Medicine, Freie Universität Berlin, Königsweg 65, 14163 Berlin, Germany.
J Dairy Sci. 2014 Jul;97(7):4333-9. doi: 10.3168/jds.2014-7997. Epub 2014 May 2.
The objective of this study was to evaluate whether milk temperature (MT) measured by automatic milking system (AMS) is a reliable indicator of body temperature of dairy cows and whether cows with fever could be detected. Data loggers (Minilog 8, Vemco Ltd., Halifax, NS, Canada) measuring body temperature were inserted for 7 ± 1 d into the vaginal cavity of 31 dairy cows and programmed to take 1 reading/min. Milk temperature was recorded at each milking event by the AMS, and values from the vaginal loggers were paired with the corresponding MT. The correlation (r) between vaginal temperature (VT) and MT was 0.52. Vaginal temperature was higher (39.1 ± 0.4°C) than MT (38.6 ± 0.7°C) with a mean difference of 0.5 ± 0.6°C. The ability of MT to identify cows with fever was assessed using 2 approaches. In the first approach, VT could indicate fever at any time of the day, whereas MT could display fever only during the milking events of a given day. Different definitions of fever based on thresholds of VT and duration exceeding these thresholds were constructed. Different thresholds of MT were tested to distinguish between cows with and without fever. The combination of 39.0°C as a threshold for MT and 39.5°C for at least 2h/d as a threshold for VT resulted in the highest combination of sensitivity (0.65) and specificity (0.65). In the second approach, we evaluated whether MT could identify cows with fever at a given milking event. A threshold of MT >38.7°C delivered the best combination of sensitivity (0.77) and specificity (0.66) when fever was defined as VT ≥39.5°C. Therefore, MT measured by AMS can be indicative of fever in dairy cows to a limited extent.
本研究的目的是评估自动挤奶系统（AMS）测量的牛奶温度（MT）是否是奶牛体温的可靠指标，以及是否能够检测出发热的奶牛。将测量体温的数据记录器（Minilog 8，Vemco有限公司，加拿大新斯科舍省哈利法克斯）插入31头奶牛的阴道腔7±1天，并设置为每分钟读取1次数据。AMS在每次挤奶时记录牛奶温度，并将阴道记录器的值与相应的MT值配对。阴道温度（VT）与MT之间的相关性（r）为0.52。阴道温度（39.1±0.4°C）高于MT（38.6±0.7°C），平均差异为0.5±0.6°C。使用两种方法评估MT识别发热奶牛的能力。在第一种方法中，VT可在一天中的任何时间指示发热，而MT仅在给定一天的挤奶过程中显示出发热。基于VT阈值和超过这些阈值的持续时间构建了不同的发热定义。测试了MT的不同阈值以区分发热奶牛和未发热奶牛。以39.0°C作为MT阈值和以39.5°C至少持续2小时/天作为VT阈值的组合，敏感性（0.65）和特异性（0.65）的组合最高。在第二种方法中，我们评估了MT是否能够在给定的挤奶事件中识别出发热奶牛。当发热定义为VT≥39.5°C时，MT>38.7°C的阈值产生了敏感性（0.77）和特异性（0.66）的最佳组合。因此，AMS测量的MT在一定程度上可指示奶牛发热。
