During his PhD, Setegn investigated social interactions in group-housed animals. Social interaction may reduce the productivity and welfare of animals. For example, social interactions lead to bite marks in group-housed mink, and to cannibalism in laying hens. In his thesis, Setegn investigated whether genetic selection with social genetic effects can reduce bite marks in group-housed mink. The results show that social genetic effects contribute a substantial amount of heritable variation for bite mark trait in group-housed mink, so that total genetic variance is large. Furthermore, he investigated whether genomic selection can be used to increase the response to selection for survival time for two lines of brown layer showing cannibalistic behaviour. The results show that response to genomic selection for one line was substantially higher than for a traditional breeding scheme, whereas for the other line the benefit of genomic selection was limited. These findings indicate there are good prospects to produce mink that have a low level of biting, and to produce laying hens that show little cannibalism.