A system for determining movements and/or orientations of an animal and/or body part of an animal provided with a first unit (2), wherein the first unit is provided with a housing (3) which is configured to be attached, in use, to an animal in a predetermined manner, at least one motion sensor (4) for detecting movements and/or orientations of the housing and for generating sensor signals which represent the detected movements, an electronic circuit (8) connected with the motion sensor (4) for processing the sensor signals generated by the at least one motion sensor for obtaining processing results, first transmitter means (10) connected with the electronic circuit (8) for transmitting the processing results, wherein the at least one motion sensor, the electronic circuit and the first transmitter means are included in the housing (3), wherein the system is configured to detect, in use, a deviation between a current orientation of the at least one motion sensor (4) with respect to a predetermined part of the animal and a supposed orientation of the at least one motion sensor with respect to the predetermined part of the animal, wherein the supposed orientation of the at least one motion sensor with respect to the predetermined part of the animal is based on the supposed predetermined manner in which the housing is connected to the animal, and wherein the system is further configured to correct for a detected deviation.
