Method for carrying out treatment steps on animals for slaughter, which are conveyed along a conveying path in a slaughter line such that they are suspended, by optically measuring the animal for slaughter, digitizing corresponding measured values and supplying the latter to a controller of at least one handling device which is used to carry out at least one of the following treatment steps: optically measuring the animal for slaughter in order to obtain a surface profile (3D image) and digitizing corresponding measurement data (first data), optically measuring a 2-dimensional or 3-dimensional area of the animal for slaughter, in which at least one treatment is to be carried out, and digitizing corresponding measurement data (second data), or optically measuring the animal for slaughter, which has been subjected to at least one treatment, in order to determine a further surface profile (3D image) and digitizing corresponding measurement data (third data), and linking the first data and the second data or the first data and the third data and supplying the linked data to the controller of the at least one handling device and/or to a further handling device for carrying out at least one treatment.