TABLE 2.

Random effects included in the four animal models for yearling temperament in American Angus cattle.

Models	Components
	${\sigma }_{CG}^2$	${\sigma }_u^2$	${\sigma }_m^2$	${\sigma }_{u,m}$	${\sigma }_p^2$
D	✓	✓	—	—	—
DMG	✓	✓	✓	✓	—
DMP	✓	✓	—	—	✓
DMGP	✓	✓	✓	✓	✓

D: reduced model fitting the additive direct genetic effect; DMG: model fitting the additive direct and maternal genetic effects; DMP: model fitting the additive direct genetic and maternal environmental effects; DMGP: complete model including additive direct genetic, maternal genetic, and maternal environmental effects; ${\sigma }_{CG}^2$ : contemporary group variance; ${\sigma }_u^2$ : additive direct genetic variance; ${\sigma }_m^2$ : maternal genetic variance; ${\sigma }_{u,m}$ : covariance between additive direct and maternal genetic effects; ${\sigma }_p^2$ : maternal environmental variance; ✓: component was included in the model.