Using an accelerometer based on inertial measurement unit to evaluate the sexual activity of the ram

International audience; The objective of this study was to evaluate the suitability of a system based on an Inertial Measurement Unit (IMU) accelerometer to assess rams’ sexual behaviour (RSB). 12 adult males (~3.5 years old;), equipped with IMU accelerometers placed between the two shoulder blades, were used in 2 parallel pen tests. The tests were replicated 6 times during the same week and consisted in 30-min. visual observations for each ram interacting with Merinos d’Arles ewes (i.e. ratio= 1 ram per 6 ewes). The RSB was then recorded according to two categories: pre-copulatory (PRE-COP: i.e. number of Anogenital Sniffs AS, Leg Kicks LK, Emission of Sounds ES, Revolve Around the Ewes RAE, Head on the Rump HR and Flehmen Fl) and copulatory (COP: number of mounts MO) behaviours. Raw accelerometer data were analysed by an algorithm developed with the Scilab software (5.4.1,2013). Overall, our results demonstrate the ability of this device to detect some, but not all, of the evaluated PRE-COP (LK, RAE and Fl) and COP behaviours (MO). In total, for the 12 rams used during the 6 tests, 80.5% of the 1,388 COP behaviours visually recorded were automatically detected by the device. Concerning the PRE-COP behaviour, from a total of 18,232 records visually recorded, the best sensitivity was performed with the LK activity (i.e. 66%, 3,002/4,484), whereas for Fl and RAE activities, the values were 57% (32/56) and 32% (67/212), respectively. The technical performance of the device evaluated here was affected both at the inter- and intra-tests levels (depending on the ram and on the behaviour parameter to be interpreted). The absence of effectiveness in interpreting other parameters was likely related to the quality of the algorithm built rather than to the device by itself. In conclusion, our preliminary results demonstrate that some of RSB can be automatically estimated by using this kind of technology. Nevertheless, more research is required to test its effectiveness regarding other RSB and with a more significant number of rams, in other seasons, etc.