Automated animal control : can discontinuous monitoring and aversive stimulation modify cattle grazing behaviour?

Grazing livestock freely select landscape resources, unless they are herded or constrained by fences. Automated animal control(AAC) systems offer an alternative to physical fences by using animal-positioning technology and aversive stimuli to deteranimals from staying in sensitive environments and so limit their impact. This paper reports on a replicated field experimentcompleted to test whether occasional stimuli (audio cue followed by a mild electric stimulus), delivered by discontinuouslyactivated AAC collars, could suffice to modify the grazing behavior of groups of cattle. Four groups of eight steers were confinedin 8-ha rectangular paddocks that had an ad libitum supplement feeder located in one end to attract cattle. The steers’ positionalinformation was recorded continuously for 3 d using a GPS receiver encased in a collar fitted around their neck. These data wereused to characterize their use of the paddocks without intervention. Subsequently a restriction zone was activated on the collars.This zone contained the supplement feeders and represented approximately 10% of the paddock area. Cattle movement wasagain monitored during a second 3-d period, in which the steers were subjected to discontinuous aversive stimuli (5 min ofstimulation followed by a random 0–30 min interval without stimulation) if they were located inside or moved into therestriction zone. Cattle visits to the restriction zone were shorter and the return interval longer when steers were subjected todiscontinuous stimulation. Overall, there was a 97% reduction in the use of the restriction zone between the first and seconddeployments. These results suggest that grazing impact can be drastically reduced by making a zone less desirable throughdiscontinuous aversive stimulation. Such a discontinuous (25% of the time on) AAC system can reduce power consumption incollars and so help overcome energy supply limitations that hinder commercial AAC applications.