Technical note: Monitoring grazing bites and walking activity with pedometers

Three types of pedometers installed on loosely fitted neck collars were investigated to determine the accuracy with which the devices measured the number of grazing bites performed by cows. The pedometer memory stored the summed number of bites over 1-h intervals for up to 10 d, and the battery had a life of more than 3 mo. The values recorded by the pedometers were linearly related to the number of bites measured by visual observation and were unaffected by rumination. The correlation coefficients between the pedometer values and the number of bites were all >0.9. Circadian and day-to-day variations in the number of grazing bites were obtained by all 3 pedometers. The regression coefficients differed among the pedometers. The pedometers also responded to the occurrence of walking steps. The values recorded by the pedometers were linearly related to the observed number of walking steps. The correlation coefficients between the pedometer values and the number of steps were all >0.9. Although the number of walking steps affected the number of grazing bites, the number of bites greatly exceeded the number of walking steps. One type of pedometer, equipped with a 2-dimensional accelerometer, was used to analyze both grazing and walking behaviors. The back-forth and right-left movements of the pedometer had similar values during walking, whereas the values of the back-forth movements were greater during grazing. I conclude that pedometers can be used to measure the number of grazing bites but that this technique requires calibration to relate the pedometer values to the number of grazing bites. Observations of the back-forth and right-left movements of pedometers on neck collars will aid in distinguishing the grazing and walking behaviors of cows.