Figure 2

Estimated systematic effects from five models. (1) Classic animal model for growth; (2) Bivariate model including growth and liability of being healthy; (3) Extension of (2) where sexual maturation is included as a third trait; (4) An extension of (3) to also include a survival-model with genetic effects; (5) An extension of (4) to include a genetic effect of growth in runts as well as in healthy animals. Model (1) did not distinguish between healthy animals and runts, but its fixed effects were compared to the fixed effects obtained for healthy animals with the other models, as most animals belonged to that category, and it is common, when health is not recorded, to assume that recorded animals are healthy.