Department of Clinical Science and Services, The Royal Veterinary College, Hatfield, UK.
Mars Horsecare UK Ltd, Equine Studies Group, Waltham Centre for Pet Nutrition, Bury St Edmunds, UK.
Equine Vet J. 2019 Nov;51(6):840-845. doi: 10.1111/evj.13130. Epub 2019 Jun 17.
Accelerometry is an accepted means of quantifying human physical activity. Quantitative physical activity tracking could be beneficial for studies into equine health and disease prevention, for example in relation to obesity management.
Validate accelerometer use in grazing horses, determine between-day repeatability, and assess the effects of pasture size on time budget (i.e. duration in each activity category).
Proof of concept.
Accelerometers (ActiGraph) were positioned at the poll. Horses underwent 5 min of observed activity in three categories: standing, grazing and ambulating. Receiver-operating characteristic curve analysis, used on ten second data epochs, calculated cut points between the activities. A 20-day study was then undertaken on 6 horses at pasture. Time in each category (per day) was deduced; a Mann Whitney U test was performed to compare standard vs. small paddock and day vs. night turn out.
Cut-off values with the optimum sensitivity (94.7-97.7%) and specificity (94.7-96.8%) were found to be <127.6 counts for standing, 127.6-702.7 counts for grazing and >702.7 counts for ambulating. Repeatability was analysed descriptively: Median (IQR) of the between-day difference in minutes standing, grazing and ambulating were 46.9 (21.3-87.9), 77.3 (40.2-124.5) and 15.6 (6.8-40.2) respectively. Median times standing and ambulating were significantly different between standard and small paddocks: standing: 8.7 vs. 10.3 h (P<0.001); ambulating: 55.7 vs. 39.6 min (P = 0.002). There was no significant difference in the median time spent grazing. There were significant differences between day and night: standing: 32.95% vs. 50.97% (P = 0.001), grazing: 60.81% vs. 46.77% (P<0.001) and ambulating: 4.57% vs. 2.40% (P<0.001).
Small sample size and lack of cross-validation of cut-off points on independent, 'unseen' data.
Accelerometry can differentiate standing, grazing and ambulating in horses. Our proof-of-concept study demonstrates modifying pasture size influences activity budgets; opening avenues into studying obesity management.
加速度计是一种公认的量化人体活动的方法。定量的体力活动追踪可能对研究马的健康和疾病预防有益，例如与肥胖管理有关。
验证在放牧马中使用加速度计，确定日间重复性，并评估牧场大小对时间预算（即每个活动类别的持续时间）的影响。
概念验证。
将加速度计（ActiGraph）放置在马的头颈部。马在三个类别中进行了 5 分钟的观察活动：站立、放牧和走动。使用十秒数据段的接收器操作特征曲线分析计算活动之间的切点。然后在 6 匹马的牧场上进行了 20 天的研究。每天每个类别的时间（每天）被推断出来；使用曼-惠特尼 U 检验比较标准与小围场和白天与夜间放牧的差异。
发现站立时的最佳灵敏度（94.7-97.7%）和特异性（94.7-96.8%）的截断值<127.6 计数，放牧时为 127.6-702.7 计数，走动时>702.7 计数。日间差异的重复性通过描述性分析进行分析：站立、放牧和走动的日间差异中位数（IQR）分别为 46.9（21.3-87.9）、77.3（40.2-124.5）和 15.6（6.8-40.2）。站立和走动的时间中位数在标准和小围场之间有显著差异：站立：8.7 与 10.3 小时（P<0.001）；走动：55.7 与 39.6 分钟（P=0.002）。放牧的时间中位数没有显著差异。日间和夜间的时间中位数有显著差异：站立：32.95%与 50.97%（P=0.001），放牧：60.81%与 46.77%（P<0.001），走动：4.57%与 2.40%（P<0.001）。
样本量小，在独立的“未见”数据上未对切点进行交叉验证。
加速度计可以区分马的站立、放牧和走动。我们的概念验证研究表明，改变牧场大小会影响活动预算；为研究肥胖管理开辟了途径。
