Janczak Andrew M, Ranheim Birgit, Fosse Torunn K, Hild Sophie, Nordgreen Janicke, Moe Randi O, Zanella Adroaldo J
Department of Production Animal Clinical Sciences, The Norwegian School of Veterinary Science, Oslo, Norway.
Vet Anaesth Analg. 2012 Nov;39(6):628-35. doi: 10.1111/j.1467-2995.2012.00737.x. Epub 2012 Jun 19.
To evaluate the stability and repeatability of measures of mechanical (nociceptive) thresholds in piglets and to examine potentially confounding factors when using a hand held algometer.
Descriptive, prospective cohort.
Forty-four piglets from four litters, weighing 4.6 ± 1.0 kg (mean ± SD) at 2 weeks of age.
Mechanical thresholds were measured twice on each of 2 days during the first and second week of life. Data were analyzed using a repeated measures design to test the effects of behavior prior to testing, sex, week, day within week, and repetition within day. The effect of body weight and the interaction between piglet weight and behaviour were also tested. Piglet was entered into the model as a random effect as an additional test of repeatability. The effect of repeated testing was used to test the stability of measures. Pearson correlations between repeated measures were used to test the repeatability of measures. Variance component analysis was used to describe the variability in the data.
Variance component analysis indicated that piglet explained only 17% of the variance in the data. All variables in the model (behaviour prior to testing, sex, week, day within week, repetition within day, body weight, the interaction between body weight and behaviour, piglet identity) except sex had a significant effect (p < 0.04 for all). Correlations between repeated measures increased from the first to the second week.
Repeatability was acceptable only during the second week of testing and measures changed with repeated testing and increased with increasing piglet weight, indicating that time (age) and animal body weight should be taken into account when measuring mechanical (nociceptive) thresholds in piglets. Mechanical (nociceptive) thresholds can be used both for testing the efficacy of anaesthetics and analgesics, and for assessing hyperalgesia in chronic pain states in research and clinical settings.
评估仔猪机械性（伤害性）阈值测量的稳定性和可重复性，并研究使用手持式痛觉计测量时潜在的混杂因素。
描述性前瞻性队列研究。
来自四窝的44头仔猪，2周龄时体重为4.6±1.0千克（均值±标准差）。
在出生后的第一周和第二周内，于2天中的每一天对每头仔猪的机械性阈值进行两次测量。使用重复测量设计分析数据，以测试测试前行为、性别、周龄、一周内的日期以及一天内的重复测量的影响。还测试了体重的影响以及仔猪体重与行为之间的相互作用。将仔猪作为随机效应纳入模型，作为可重复性的额外测试。重复测试的影响用于测试测量的稳定性。重复测量之间的Pearson相关性用于测试测量的可重复性。方差成分分析用于描述数据的变异性。
方差成分分析表明，仔猪仅解释了数据中17%的方差。模型中的所有变量（测试前行为、性别、周龄、一周内的日期、一天内的重复测量、体重、体重与行为之间的相互作用、仔猪身份）除性别外均有显著影响（所有p<0.04）。重复测量之间的相关性从第一周增加到第二周。
仅在测试的第二周可重复性是可接受的，并且测量值随重复测试而变化，并随仔猪体重增加而增加，这表明在测量仔猪的机械性（伤害性）阈值时应考虑时间（年龄）和动物体重。机械性（伤害性）阈值可用于测试麻醉药和镇痛药的疗效，以及在研究和临床环境中评估慢性疼痛状态下的痛觉过敏。
