Table 4. Estimate of variance components by single trait animal model for birth weight (BW), body weight at one month (BW4), body weight at two months (BW8) and weaning weight (BW12)

Parameter	BW	BW4	BW8	BW12
σ2a	0.258	2.000	3.130	3.276
σ2e	0.164	6.660	9.245	9.150
σ2p	0.189	8.660	12.376	12.426
h2 ± SE	0.14 ± 0.07	0.23 ± 0.09	0.25 ± 0.09	0.26 ± 0.09

σ²_a, σ²_e, σ²_p and h² are additive genetic variance, residual variance, phenotypic variance and direct heritability respectively.