Laboratory of Animal Production System, Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
Digital Innovation Center, Furukawa Electric Group, Yokohama, Japan.
Anim Sci J. 2023 Jan-Dec;94(1):e13830. doi: 10.1111/asj.13830.
To assess the usefulness of a commercially available indoor positioning system for monitoring the resting time and moving distance in group-housed dairy calves as indicators of their health status, five dairy calves were housed in a free barn, and their coordinate was recorded. The mean displacement (cm/s) within a minute showed a double-mixture distribution. Actual observations revealed that the minutes in the first distribution with shorter displacement were mostly the time that the calves spent lying. To predict the daily lying time and moving distance, a mixed distribution was divided at a threshold value. The mean sensitivity (the proportion of total minutes predicted correctly as lying, in total minutes observed lying) was more than 92%. The daily fluctuation in lying time correlated well with the actual lying time (r = 0.758, p < 0.01). The range of fluctuations was 740-1308 min/day and 724-1269 m/day for daily lying time and moving distance, respectively. The rectal temperature was correlated with daily lying time (r = 0.441, p < 0.001) and distance moved (r = 0.483, p < 0.001). The indoor positioning system can be a useful tool for early illness detection in calves before the onset of symptoms in group-housing systems.
为了评估一种市售的室内定位系统在监测群体饲养奶牛犊牛的休息时间和移动距离方面的有用性，作为其健康状况的指标，将五头奶牛犊安置在自由畜舍中，并记录其坐标。一分钟内的平均位移（cm/s）呈双峰分布。实际观察表明，第一个较短位移分布的分钟数主要是奶牛犊躺着的时间。为了预测每日躺卧时间和移动距离，在阈值处对混合分布进行了划分。平均灵敏度（预测为躺卧的总分钟数中正确预测的比例，占观察到的总躺卧分钟数）超过 92%。躺卧时间的日波动与实际躺卧时间相关性良好（r=0.758，p<0.01）。每日躺卧时间和移动距离的波动范围分别为 740-1308 分钟/天和 724-1269 米/天。直肠温度与每日躺卧时间（r=0.441，p<0.001）和移动距离（r=0.483，p<0.001）相关。室内定位系统可以成为群体饲养系统中症状出现之前早期检测犊牛疾病的有用工具。
