Table 2.

Estimates of variance components, variance component ratios, and SE from animal and sire models for weaning (WFEC) and postweaning (PWFEC) fecal egg counts for Katahdin lambs

Animal models			Sire models
Itema	WFEC	PWFEC	Itemb	WFEC	PWFEC
σ2a	0.06 ± 0.02	0.09 ± 0.02	σ2s	0.02 ± 0.01	0.04 ± 0.01
σ2l	0.05 ± 0.01	0.04 ± 0.01	σ2l	0.07 ± 0.01	0.04 ± 0.01
σ2e	0.23 ± 0.02	0.25 ± 0.01	σ2e	0.26 ± 0.01	0.29 ± 0.01
σ2p	0.35 ± 0.01	0.37 ± 0.01	σ2p	0.35 ± 0.01	0.37 ± 0.01
h 2	0.18 ± 0.05	0.23 ± 0.04	h 2	0.26 ± 0.08	0.46 ± 0.08
l 2	0.15 ± 0.03	0.10 ± 0.03	l 2	0.14	0.00
t fs	0.23	0.23	t fs	0.27	0.23

^aFor animal models, σ²_a = direct additive variance; σ²_l = variance due to litter effects; σ²_e = residual variance; σ²_p = phenotypic variance = σ²_a + σ²_l + σ²_e; h² = heritability = σ²_a/σ²_p; l² = σ²_l/σ²_p; and t_fs = the full-sib correlation = (0.5σ²_a + σ²_l)/σ²_p. The SE of t_fs was not available.

^bFor sire models, σ²_s = direct additive variance among sires; σ²_l = variance due to litter effects and included the direct additive variance among dams; σ²_e = residual variance and included the Mendelian sampling variance for direct additive effects; and σ²_p = phenotypic variance was estimated as σ²_s + σ²_l + σ²_e. For comparability with estimates derived from animal models, h² was estimated as 4σ²_s/σ²_p, l² was estimated as (σ²_l − σ²_s)/σ²_p, and t_fs was estimated as (½h² + l²). The SE of t_fs and l² were not available for sire models.