The regulation aims at revising the legislation in force - Council Directive 93/119/EC on the protection of animals at the time of killing or slaughter in the light of new technical and scientific elements. It also introduces a new approach - mirroring the one followed in food safety field - increasing operator’s responsibilities concerning welfare.
http://www.consilium.europa.eu/uedocs/cms_data/docs/pressdata/en/agricult/108682.pdf