Ungar Eugene David, Horn Reuven
Department of Natural Resources, Institute of Plant Sciences, Agricultural Research Organization (ARO), Volcani Center, 68 HaMaccabim Road, P.O. Box 15159, Rishon LeZion 7505101, Israel.
Rangeland Service, Ministry of Agriculture and Food Security, P.O. Box 30, Rishon LeZion 5025001, Israel.
Sensors (Basel). 2024 Dec 24;25(1):8. doi: 10.3390/s25010008.
Acoustic monitoring facilitates the detailed study of herbivore grazing by generating a timeline of sound bursts associated with jaw movements (JMs) that perform bite or chew actions. The unclassified stream of JM events was used here in an observational study to explore the notion of "grazing time". Working with shepherded goat herds in a wooded landscape, a horn-based acoustic sensor with a vibration-type microphone was deployed on a volunteer animal along each of 12 foraging routes. The software-generated timeline of unclassified JMs contained a total of 334,582 events. After excluding rumination bouts, minutely JM rates showed a broad, non-normal distribution, with an overall mean of 61 JM min. The frequency distribution of inter-JM interval values scaled logarithmically, with a peak in the region of 0.43 s representing a baseline interval that generates the unconstrained, more-or-less regular, rhythm of jaw movement (≈140 JM min). This rhythm was punctuated by interruptions, for which duration scaled logarithmically, and which were primarily related to the search phase of the intake process. The empirical time accumulation curve shows the contribution of the inter-JM interval to the total foraging time and provides a penetrating profile of how the animal interacted with the foraging environment. The sum total of time along a foraging route spent at a near-potential JM rate was only ≈1 h, whereas sub-potential rates containing intervals as long as ≈30 s accounted for the bulk of the foraging route. The dimensionless behavioral grazing intensity was defined as the product of the number of ingestive JMs performed and the baseline interval, divided by the duration of the foraging route (excluding rumination). Values were mostly <0.5 for the foraging routes examined. This has implications for how animal presence should be translated to grazing pressure and for how long animals need to forage to meet their nutritional requirements.
声学监测通过生成与执行咬或咀嚼动作的颌运动（JMs）相关的声音爆发时间线，有助于对食草动物的啃食进行详细研究。在一项观察性研究中，这里使用未分类的JM事件流来探索“啃食时间”的概念。在树木繁茂的景观中，与放牧的山羊群合作，将一个带有振动型麦克风的基于喇叭的声学传感器部署在12条觅食路线上的每一条路线的一只志愿动物身上。软件生成的未分类JM时间线总共包含334,582个事件。排除反刍发作后，每分钟的JM率呈现出广泛的、非正态分布，总体平均值为每分钟61次JM。JM间隔值的频率分布呈对数缩放，在0.43秒左右的区域出现峰值，代表产生无约束的、或多或少有规律的颌运动节奏（约每分钟140次JM）的基线间隔。这种节奏被中断打断，中断的持续时间呈对数缩放，并且主要与摄入过程的搜索阶段有关。经验时间累积曲线显示了JM间隔对总觅食时间的贡献，并提供了动物与觅食环境相互作用方式的深入概况。在接近潜在JM率下沿觅食路线花费的总时间仅约为1小时，而包含长达约30秒间隔的次潜在率占了觅食路线的大部分。无量纲行为啃食强度定义为执行的摄食性JM次数与基线间隔的乘积，除以觅食路线的持续时间（不包括反刍）。在所检查的觅食路线中，值大多<0.5。这对于应如何将动物的存在转化为啃食压力以及动物需要觅食多长时间才能满足其营养需求具有启示意义。
