Evidence for genetic variation in bite marks in group housed mink

Abstract

There is evidence from several species (e.g. poultry) that selection can contribute to reduced aggression in groups, and selection thus could be one way of reducing aggression in group housed mink. On this background, a selection experiment was started, aiming at reducing the number of bite marks on the skin side. This study describes variation in bite marks in the three generations. The study includes evaluation of bite marks on a total of 1986 mink in group housing. We hypothesise that bite marks might be influenced by both direct genetic effects and social genetic effects. Direct genetic effects refers to the effect of the animals own genotype and social effects refer to the effects of the genotype of the other animal in the group. Both direct and social genetic effects contribute to the variation in bite-marks in mink. Social genetic effect and the covariance between direct and social genetic effect explains more than 5 times the variation in bite marks explained by direct genetic effect. This is true in bite marks for the neck, body, and tail region as well as for the average of these regions. Therefore selection which take in to account social genetic effect will be successful to decrease bite marks in mink.