School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia.
Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Armidale, NSW, Australia.
PeerJ. 2023 Feb 2;11:e14730. doi: 10.7717/peerj.14730. eCollection 2023.
Understanding the effects of repeated testing on behaviour is essential for behavioural tests that are re-applied to the same individuals for research and welfare assessment purposes. Assessing the repeatability of behaviour can also help us understand the influence of persistent traits transient states on animal responses during testing. This study examined the repeatability of behavioural responses in an attention bias test developed for sheep as a measure of affective state. Sheep were assessed in the attention bias test three times ( = 81 sheep), with testing occurring at intervals of 1 year then 2 weeks. During testing, individual sheep were exposed to a dog located behind a window for 3 s in a 4 × 4 m arena, then the dog was obscured from view, removed and sheep behaviours were recorded for 180 s. We hypothesised that behaviours in the test would have moderate-high repeatability but that the mean behavioural responses would change over consecutive trials as sheep habituated to the test environment. To estimate repeatability, data were modelled using restricted maximum likelihood linear mixed-effects models, fitting animal ID as a random effect. Vigilance behaviour, defined as having the head at or above shoulder height, was moderately repeatable (r = 0.58). Latency to eat (r = 0.20) and duration spent looking towards the previous location of the dog (attention to the dog wall) (r = 0.08) had low repeatability. Mean latency to eat did not differ significantly between trials ( = 0.2) and mean vigilance behaviour tended to decrease over the trials ( = 0.07). Mean duration of attention to the dog wall significantly decreased across the trials ( < 0.001), while mean zones crossed increased ( < 0.001), as did behaviours directed towards the exit door such as duration in proximity and pawing at the door. Overall, vigilance behaviour was moderately repeatable, suggesting it may have been driven by temperament or personality traits, while attention and feeding behaviours may have been more influenced by transient affective states or other factors, however further research is needed to better tease apart these potential effects. Sheep demonstrated some habituation to the test over consecutive trials. Care should therefore be taken during future application of the test to ensure all animals undergoing attention bias testing have equivalent experience for a valid interpretation of their relative behavioural responses.
了解重复测试对行为的影响对于为研究和福利评估目的而对同一个体重复应用的行为测试至关重要。评估行为的可重复性也有助于我们了解在测试过程中持久特征和瞬态状态对动物反应的影响。本研究检查了作为情感状态衡量标准的绵羊注意力偏差测试中行为反应的可重复性。绵羊在注意力偏差测试中进行了三次评估（= 81 只绵羊），测试间隔为 1 年和 2 周。在测试过程中，个体绵羊在 4×4 米的竞技场中暴露于窗户后面的狗 3 秒钟，然后将狗遮挡起来，观察 180 秒内绵羊的行为。我们假设测试中的行为将具有中等高度的可重复性，但随着绵羊适应测试环境，连续试验的平均行为反应会发生变化。为了估计可重复性，使用受限最大似然线性混合效应模型对数据进行建模，将动物 ID 拟合为随机效应。警觉行为（定义为头部高于或等于肩部高度）具有中等可重复性（r = 0.58）。潜伏期（r = 0.20）和注视狗墙的时间（r = 0.08）的时间短，可重复性低。潜伏期的平均值在试验之间没有显著差异（= 0.2），警觉行为的平均值在试验中趋于减少（= 0.07）。对狗墙的注意力的平均值在试验中显著降低（<0.001），而穿过的平均区域增加（<0.001），靠近出口门的行为（如接近的持续时间和拍打门）也增加。总的来说，警觉行为具有中等的可重复性，这表明它可能受到气质或个性特征的驱动，而注意力和进食行为可能更多地受到瞬态情感状态或其他因素的影响，然而，需要进一步研究以更好地梳理这些潜在影响。绵羊在连续试验中表现出对测试的一些适应。因此，在未来应用该测试时应谨慎行事，以确保所有接受注意力偏差测试的动物都具有相同的经验，以便对其相对行为反应进行有效解释。
