Observing grazing patterns with collar-mounted accelerometers and spatial data

Kilian Obermeyer ^1,2* Manfred Kayser ^2,3 Johannes Isselstein ^2,4

• ¹ Agricultural center for cattle, grassland, dairy, game and fisheries of Baden-Württemberg, Aulendorf, Germany
• ² Grassland Science, Department of Crop Science, University of Goettingen, Göttingen, Germany
• ³ Geo-Laboratory, Department of Geography, University of Vechta, Vechta, Germany
• ⁴ Centre of Biodiversity and Sustainable Land Use, Faculty of Agricultural Sciences, University of Göttingen, Göttingen, Lower Saxony, Germany

In pasture-based dairy farming, animal behaviour data can improve data-driven pasture management.In pasture-based dairy farming using information on animal behaviour could contribute to the development of more data-driven pasture management systems. Information on grazing behaviour of dairy cows can be retrieved from sensor-based data. However, this approach usually requires sophisticated sensor equipment and involves labour intensive animal observations. As an alternative we investigated the use of data from simple and commonly used collar-mounted accelerometers and global navigation system services (GNSS) receivers. In our on-farm study, cows grazed in a rotational or in a continuous grazing system, with a higher sward or lower sward height, respectively. As an indicator of grazing activity the overall dynamic body acceleration (ODBA) was calculated from accelerometer data. After differentiating the grazing process (forage uptake) into grazing with grazing steps (move to the next feeding station) and without grazing steps (true standing) from GNSS data, we found only a negligible effect of grazing steps on ODBA. The ODBA was higher in short swards (3.47 m s -2 ) than in tall swards (2.88 m s -2 ). The ODBA was also affected Forma Forma Forma by the time of the day with major grazing activity around dusk. Our findings show the potential of simple accelerometers on collars in researching grazing patterns, monitoring cattle, and for the use in pasture management. The ODBA can be calculated from any three-dimensional accelerometer also from existing commercial technology which allow a wide in-field application.