Social genetic effects for growth in pigs differ between boars and gilts

Table 2 Parameter estimates (standard errors in brackets) from a univariate classical and a social genetic effects model for average daily gain (g/day) across boars and gilts

Component	Classical	Social
\({\upsigma}_{{{\mathbf{A}}_{\text{D}} }}^{2}\)	2550.1 (159.5)	2521.4 (158.6)
\({\upsigma}_{{{\mathbf{A}}_{\text{S}} }}^{2}\)		7.4 (2.6)
\({\upsigma}_{{{\mathbf{A}}_{\text{DS}} }}\)		− 2.49 (16.8)
\({\upsigma}_{g}^{2}\)	1115.9 (35.1)	1081.9 (36.9)
\({\upsigma}_{l}^{2}\)	727.4 (36.9)	725.3 (44.1)
\({\upsigma}_{e}^{2}\)	7037.6 (86.6)	7015.4 (87.9)
\(h^{2} /{\text{T}}^{2}\)	0.223 (0.014)	0.234 (0.014)
\(r_{{{\mathbf{A}}_{\text{D}} ,{\mathbf{A}}_{\text{S}} }}\)		− 0.24 (0.126)
\({\upsigma}_{TBV}^{2}\)		2654.4 (106.8)
\(\Delta {\text{LogL}}\)		8.5 (P < 0.05)

\({\upsigma}_{{{\mathbf{A}}_{\text{D}} }}^{2}\) = direct genetic variance
\({\upsigma}_{{{\mathbf{A}}_{\text{S}} }}^{2}\) = social genetic variance
\({\upsigma}_{{{\mathbf{A}}_{\text{DS}} }}\) = direct-social covariance
\({\upsigma}_{g}^{2}\) = variance of group
\({\upsigma}_{l}^{2}\) = variance of litter
\({\upsigma}_{e}^{2}\) = residual variance
h² = heritability
T² = total heritable variation
\(r_{{{\mathbf{A}}_{\text{D}} ,{\mathbf{A}}_{\text{S}} }}\) = genetic correlation between direct and social genetic effect
\({\upsigma}_{TBV}^{2}\) = variance of the total breeding value
\(\Delta {\text{LogL}}\) = reduction in − 2Log Likelihood compared to the classical model, P values from a likelihood ratio test with 2 degrees of freedom in parentheses

ISSN: 1297-9686