Investigating cattle responses to acoustic signals to extend the functions of virtual fencing collars

Abstract

Virtual fencing uses collars that emit acoustic signals and, if necessary, electric pulses to indicate the fence line. In Europe, legalization is lacking because of animal welfare concerns over electric pulses. This study investigated whether acoustic signals can replace electric pulses and influence grazing livestock movement. Two experiments with eight to ten Fleckvieh heifers and a prototype virtual fencing collar that emits directional acoustic signals and vibrations were conducted over 36 days in 2023 and 32 days in 2024. In the first experiment, the heifers’ responses to different acoustic signals and vibrations were analyzed. Generalized linear mixed effect models with data from behavioral observations and heart rate measurements revealed that the heifers were unimpressed by the signals, as often no response was observed and the changes in heart rate appeared to be unrelated to the signaling. Furthermore, clear signs of quick habituation were found, suggesting the need to test different signals. In the second experiment, we tested whether the heifers could be taught to adjust their walking direction to directional acoustic signals while moving toward a feed source. The training protocol used proved ineffective in teaching heifers to associate an acoustic signal with a walking direction, as generalized linear mixed effect models revealed that the heifers approached the indicated feed source in less than 50 % of the cases. Instead, side preferences were detected for some heifers. A different training protocol is recommended for further studies to test whether directional acoustic signals can influence the movement of cattle.