COI (30) of dam and litter size. Maternal Wright's inbreeding coefficient over 30 generations and litter size. All: registered litter size; coi_30_dam: maternal Wright's inbreeding coefficient over 30 generations. Graphical rendering of significant effects in table 4. Although these effects are highly significant, actual influence on litter size remains low, as expressed by the low coefficient of determination (R2 = 0.0341).