PDF(Pubmed)
Abstract：
Virtual fencing (VF) is a modern fencing technology that requires the animal to wear a device (e.g., a collar) that emits acoustic signals to replace the visual cue of traditional physical fences (PF) and, if necessary, mild electric signals. The use of devices that provide electric signals leads to concerns regarding the welfare of virtually fenced animals. The objective of this review is to give an overview of the current state of VF research into the welfare and learning behavior of cattle. Therefore, a systematic literature search was conducted using two online databases and reference lists of relevant articles. Studies included were peer-reviewed and written in English, used beef or dairy cattle, and tested neck-mounted VF devices. Further inclusion criteria were a combination of audio and electrical signals and a setup as a pasture trial, which implied that animals grazed in groups on grassland for 4 h minimum while at least one fence side was virtually fenced. The eligible studies (n = 13) were assigned to one or two of the following categories: animal welfare (n studies = 8) or learning behavior (n studies = 9). As data availability for conducting a meta-analysis was not sufficient, a comparison of the means of welfare indicators (daily weight gain, daily lying time, steps per hour, daily number of lying bouts, and fecal cortisol metabolites [FCM]) for virtually and physically fenced animals was done instead. In an additional qualitative approach, the results from the welfare-related studies were assembled and discussed. For the learning behavior, the number of acoustic and electric signals and their ratio were used in a linear regression model with duration in days as a numeric predictor to assess the learning trends over time. There were no significant differences between VF and PF for most welfare indicators (except FCM with lower values for VF; P = 0.0165). The duration in days did not have a significant effect on the number of acoustic and electric signals. However, a significant effect of trial duration on the ratio of electric-to-acoustic signals (P = 0.0014) could be detected, resulting in a decreasing trend of the ratio over time, which suggests successful learning. Overall, we conclude that the VF research done so far is promising but is not yet sufficient to ensure that the technology could not have impacts on the welfare of certain cattle types. More research is necessary to investigate especially possible long-term effects of VF.
Virtual fencing is a GPS-enabled fencing technology with the potential for improved livestock and pasture management, as well as socioeconomic and environmental benefits. However, the missing visual cue of a physical fence and the use of electric signals to ensure animals stay within the invisible boundary raise ethical and animal welfare concerns regarding the animal’s ability to understand and learn the technology and the stress and anxiety associated with these processes. In this review, data from studies investigating the welfare and learning behaviors of virtually fenced animals were collected and analyzed to give an overview of this research field. It shows that the welfare of cattle in extensive systems is not adversely affected by the virtual fencing system, and the animals learn to avoid the electric signals. However, more research is necessary, especially over longer periods of time and with cows in intensive grazing systems, to ensure the welfare of virtually fenced cattle.
Virtual fencing is a GPS-enabled fencing technology with the potential for improved livestock and pasture management, as well as socioeconomic and environmental benefits. However, the missing visual cue of a physical fence and the use of electric signals to ensure animals stay within the invisible boundary raise ethical and animal welfare concerns regarding the animal’s ability to understand and learn the technology and the stress and anxiety associated with these processes. In this review, data from studies investigating the welfare and learning behaviors of virtually fenced animals were collected and analyzed to give an overview of this research field. It shows that the welfare of cattle in extensive systems is not adversely affected by the virtual fencing system, and the animals learn to avoid the electric signals. However, more research is necessary, especially over longer periods of time and with cows in intensive grazing systems, to ensure the welfare of virtually fenced cattle.
摘要：
虚拟围栏（VF）是一种现代围栏技术，要求动物佩戴发出声音信号的设备（例如项圈），以取代传统物理围栏（PF）的视觉提示，如有必要,温和的电信号。使用提供电信号的设备会引起人们对实际上围栏动物的福利的担忧。这篇评论的目的是概述VF对牛的福利和学习行为的研究现状。因此,使用两个在线数据库和相关文章的参考文献列表进行了系统的文献检索。纳入的研究是同行评审的，用英语写的，用过的牛肉或奶牛，并测试了颈部安装的VF设备。进一步的纳入标准是音频和电信号的组合，以及作为牧场试验的设置，这意味着动物在草地上成群放牧至少四个小时，而至少一个围栏侧面实际上是围栏。符合条件的研究（n=13）被分配到以下类别中的一个或两个：动物福利（n研究=8）或学习行为（n研究=9）。由于进行荟萃分析的数据可用性不足，福利指标(每日体重增加，每天说谎的时间，每小时步数,每天撒谎的次数，相反，对虚拟和物理围栏动物进行了粪便皮质醇代谢物（FCM））。在另一种定性方法中，我们对福利相关研究的结果进行了汇总和讨论.对于学习行为，在线性回归模型中,使用声信号和电信号的数量及其比率作为数值预测因子,以天数为单位评估随时间变化的学习趋势.大多数福利指标的VF和PF之间没有显着差异（FCM的VF值较低；P=0.0165）。以天为单位的持续时间对声和电信号的数量没有显着影响。然而,可以检测到试验持续时间对电信号与声信号之比的显著影响(P=0.0014)，导致该比率随时间呈下降趋势，这表明成功的学习。总的来说,我们得出的结论是，到目前为止所做的VF研究是有希望的，但还不足以确保该技术不会对某些牛的福利产生影响。需要更多的研究来调查尤其是VF可能的长期影响。
