Brunberg E I, Bergslid I K, Bøe K E, Sørheim K M
1NORSØK - Norwegian Institute for Organic Agriculture,Gunnars veg 6,N-6630 Tingvoll,Norway.
3Department of Animal and Aquacultural Sciences,Norwegian University of Life Sciences,PO Box 5003,N-1432 Ås,Norway.
Animal. 2017 Nov;11(11):2045-2050. doi: 10.1017/S1751731117000891. Epub 2017 May 11.
The Nofence technology is a GPS-based virtual fencing system designed to keep sheep within predefined borders, without using physical fences. Sheep wearing a Nofence collar receive a sound signal when crossing the virtual border and a weak electric shock if continuing to walk out from the virtual enclosure. Two experiments testing the functionality of the Nofence system and a new learning protocol is described. In Experiment 1, nine ewes with their lambs were divided into groups of three and placed in an experimental enclosure with one Nofence border. During 2 days, there was a physical fence outside the border, during Day 3 the physical fence was removed and on Day 4, the border was moved to the other end of the enclosure. The sheep received between 6 and 20 shocks with an average of 10.9±2.0 (mean±SE) per ewe during all 4 days. The number of shocks decreased from 4.38±0.63 on Day 3 (when the physical fence was removed) to 1.5±0.71 on Day 4 (when the border was moved). The ewes spent on average 3%, 6%, 46% and 9% of their time outside the border on Days 1, 2, 3 and 4, respectively. In Experiment 2, 32 ewes, with and without lambs, were divided into groups of eight and placed in an experimental enclosure. On Day 1, the enclosure was fenced with three physical fences and one virtual border, which was then increased to two virtual borders on Day 2. To continue to Day 3, when there was supposed to be three virtual borders on the enclosure, at least 50% of the ewes in a group should have received a maximum of four shocks on Day 2. None of the groups reached this learning criterion and the experiment ended after Day 2. The sheep received 4.1±0.32 shocks on Day 1 and 4.7±0.28 shocks on Day 2. In total, 71% of the ewes received the maximum number of five shocks on Day 1 and 77% on Day 2. The individual ewes spent between 0% and 69.5% of Day 1 in the exclusion zone and between 0% and 64% on Day 2. In conclusion, it is too challenging to ensure an efficient learning and hence, animal welfare cannot be secured. There were technical challenges with the collars that may have affected the results. The Nofence prototype was unable to keep the sheep within the intended borders, and thus cannot replace physical fencing for sheep.
诺芬斯技术是一种基于全球定位系统（GPS）的虚拟围栏系统，旨在让绵羊待在预先设定的边界内，无需使用实体围栏。佩戴诺芬斯项圈的绵羊在越过虚拟边界时会收到声音信号，若继续走出虚拟围栏则会受到轻微电击。本文描述了两项测试诺芬斯系统功能的实验以及一种新的学习协议。在实验1中，9只母羊及其羔羊被分成3组，放置在一个有一条诺芬斯边界的实验围栏中。在两天时间里，边界外有实体围栏，第3天拆除实体围栏，第4天边界移至围栏的另一端。在这4天里，每只母羊受到6至20次电击，平均为10.9±2.0（均值±标准误）。电击次数从第3天（拆除实体围栏时）的4.38±0.63次减少到第4天（边界移动时）的1.5±0.71次。母羊在第1天、第2天、第3天和第4天分别平均有3%、6%、46%和9%的时间处于边界之外。在实验2中，32只母羊（有无羔羊）被分成8组，放置在一个实验围栏中。第1天，围栏用三道实体围栏和一道虚拟边界围起来，第2天虚拟边界增加到两道。到第3天，围栏上应该有三道虚拟边界，此时一组中至少50%的母羊在第2天最多应受到4次电击。没有一组达到这个学习标准，实验在第2天后结束。绵羊在第1天受到4.1±0.32次电击，第2天受到4.7±0.28次电击。总体而言，71%的母羊在第1天和77%的母羊在第2天受到了最多5次电击。每只母羊在第1天有0%至69.5%的时间处于禁区，在第2天有0%至64%的时间处于禁区。总之，确保高效学习极具挑战性，因此无法保障动物福利。项圈存在技术问题，可能影响了实验结果。诺芬斯原型无法让绵羊待在预期边界内，因此不能替代绵羊的实体围栏。
