Daily grazing time of free-ranging cattle as an indicator of available feed

The hypothesis of this research was that livestock movement is related to feed availability and therefore spatial and temporal livestock information. Collected through autonomous position tracking devices, this may be used as an indicator of available feed. Two separate experiments were undertaken in which grazing cattle were tracked with store-on-board GPS. Additionally, pasture biomass was monitored with active optical sensing and manual cuts throughout the duration of the experiments. Cattle grazing behaviour was determined from the GPS data with speed-based behaviour models. The time cattle spent grazing per day altered with changing pasture biomass in both experiments. The daily time spent grazing was commonly found to initially be almost constant before following a quadratic trend, increasing before decreasing as available biomass declined. Development of behaviour models for autonomous livestock monitoring could assist producers with decisions related to rotation and feed management.