Raundal Peter M, Andersen Pia H, Toft Nils, Forkman Björn, Munksgaard Lene, Herskin Mette S
Knowledge Centre for Agriculture, Cattle, Aarhus N, Denmark.
Vet Anaesth Analg. 2014 Nov;41(6):660-9. doi: 10.1111/vaa.12159. Epub 2014 Apr 16.
To examine the use of handheld methodology to assess mechanical nociceptive threshold (MNT) on cows kept loose-housed.
Prospective randomized partial cross-over experimental study. A one-factor (test day) design was used to evaluate MNT over time.
One hundred and fifteen healthy, loose-housed Danish Holstein cattle.
We evaluated intra-individual variation, inter-observer agreement and variation over time of MNT using two handheld devices and two stimulation sites. Mechanical, ramped stimulations were performed with an algometer (6.5 mm diameter steel probe, 0-10.0 kgf) or an electronic von Frey device (plastic tip with diameter 0.8 mm, 0-1000 gf). Each cow received 5-6 consecutive stimulations within a 2 × 5 cm skin area on the dorsal or lateral aspect of the left third metatarsus until an avoidance reaction occurred. We investigated the difference in precision [expressed as coefficient of variation (CV)] between the combinations of devices and stimulation sites. The inter-observer agreement and the difference in MNT between test day 1, 3, 7, 10 and 24 were investigated for selected combinations. Data were analysed in mixed models and Bland-Altman as relevant.
The CVs did not differ [range 0.34-0.52 (p = 0.1)]. Difference between observers (95% limits) was 0.2 kgf (2.8) and 4 gf (369) for the algometer and von Frey device, respectively. Mechanical nociceptive threshold increased from 361 on test day one to 495 gf on test day 24 (p < 0.01).
All methods showed a high degree of intra-individual variation, and no combination of device and stimulation site showed superior precision. Mean difference between observers was low, and MNT was not consistent over time. Further development of the methods is required before they can be used in research to investigate possible relations between claw lesions and hyperalgesia.
研究使用手持方法评估散养奶牛的机械性伤害感受阈值（MNT）。
前瞻性随机部分交叉实验研究。采用单因素（测试日）设计来评估随时间变化的MNT。
115头健康的散养丹麦荷斯坦奶牛。
我们使用两种手持设备和两个刺激部位评估了MNT的个体内变异、观察者间一致性和随时间的变化。使用痛觉计（直径6.5毫米的钢探头，0 - 10.0千克力）或电子von Frey装置（直径0.8毫米的塑料尖端，0 - 1000克力）进行机械性斜坡刺激。每头奶牛在左第三跖骨背侧或外侧2×5厘米的皮肤区域内接受5 - 6次连续刺激，直到出现回避反应。我们研究了设备和刺激部位组合之间精度差异[以变异系数（CV）表示]。针对选定组合，研究了观察者间一致性以及第1、3、7、10和24天测试日之间MNT的差异。根据相关性，在混合模型和Bland - Altman中分析数据。
CVs无差异[范围0.34 - 0.52（p = 0.1）]。对于痛觉计和von Frey装置，观察者间差异（95%界限）分别为0.2千克力（2.8）和4克力（369）。机械性伤害感受阈值从测试日1的361克力增加到测试日24的495克力（p < 0.01）。
所有方法均显示出高度的个体内变异，且没有设备和刺激部位的组合显示出更高的精度。观察者间平均差异较低，且MNT随时间不一致。在这些方法可用于研究爪部病变与痛觉过敏之间的可能关系之前，需要进一步改进。
