Interpretation of data from GPS-collars with movement sensors on cattle :

Abstract: In this study GPS-collars with movement sensors were used on Nelore heifers on relatively small pastures in southern Brazil. Visual observations of the collared animals were made, so that data on the animal’s actual behaviour could be compared to the data from the collars. The aim of the study was to verify and discuss the information about cattle behaviour provided by the GPS collars and the movement sensors in them. No conciderable difference between the counts from the left/right and the forward/backward movement sensors could be detected. Hence the sum of the data from both of the movement sensors was used. Different behaviours and combinations of behaviours were tested for correlation to the sum of the movement data, and to distance traveled between the GPS-locations. It was not possible to determine if the animals were ruminating or not. High counts in the sum of the activity data from the movement sensors with some certainity indicated ‘Grazing’, and low counts in the movement sensor data indicated resting. It was not possible to determine from this study if longer distances traveled between the GPS-locations meant walking, but that is likely the case. The main conclusion from this study is the clear connection between observed grazing and walking behaviour on one hand and the collars recorded activity in movement sensors and distance between GPS-locations on the other. Also, the relationship between the collars data and observed lying and standing are clear as long as the animals are not ruminating.