[en] Improving the monitoring of rumination in cattle could help in assessing of the welfare status and their risk of acidosis. In this work, the monitoring of cattle’s behaviour was performed using the inertial measurement unit (IMU) present in smartphones mounted on the neck of cows. The processing of both time and frequency domains of the IMU signals was capable to detect accurately the main behaviours (grazing, rumination and other) and highlight the characteristics of the rumination process. The algorithm for analysis of rumination was more accurate for grazing cattle than for silage-fed cattle in stables.