Plumage condition in laying hens: genetic parameters for direct and indirect effects in two purebred layer lines

Table 4 Contribution of direct and indirect genetic effects to total heritable variation of FCS

		Contribution to the total heritable variation¹(%)
Line	Region	Direct²	Indirect³	Covariance⁴	Total non-direct⁵
W1	Neck	30.5	56.0	13.5	69.5
	Back	29.4	57.2	13.4	70.6
	Rump	8.4	98.4	-6.8	91.6
	Belly	55.6	34.9	9.4	44.4
	Total	22.0	68.9	9.1	78.0
WB	Neck	20.6	94.8	-15.4	79.4
	Back	7.5	114.7	-22.2	92.5
	Rump	6.3	96.0	-2.3	93.7
	Belly	27.5	50.7	21.8	72.5
	Total	10.1	106.6	-16.7	89.9

Contribution of direct genetic effects (direct), indirect genetic effects (indirect), the covariance between direct and indirect genetic effects (covariance), and total non-direct genetic effects (total non-direct) to total heritable variation of FCS in different body regions for two lines (W1, WB); ¹Total heritable variation ( $σ_{TBV}^{2} = σ_{A_{D}}^{2} + 2 (n - 1) σ_{A_{DS}} + {(n - 1)}^{2} σ_{A_{S}}^{2}$ ; ²direct = $σ_{A_{D}}^{2}$ ; ³indirect = ${(n - 1)}^{2} σ_{A_{S}}^{2}$ ; ⁴covariance = $2 (n - 1) σ_{A_{DS}}$ ; ⁵total non-direct = $2 (n - 1) σ_{A_{DS}} + {(n - 1)}^{2} σ_{A_{S}}^{2}$ .

ISSN: 1297-9686