Prediction of genetic merit for growth rate in pigs using animal models with indirect genetic effects and genomic information

Table 2 Definitions of variance components and heritability statistics

	Classic	Indirect
\(\sigma_{TBV}^{2}\)	None	\(\sigma_{{a_{D} }}^{2} + 2\left( {\bar{n} - 1} \right)\sigma_{{a_{D,I} }} + \left( {\bar{n} - 1} \right)^{2} \sigma_{{a_{I} }}^{2}\)
\(\sigma_{env}^{2}\)	\(\sigma_{u}^{2} + \sigma_{{l_{D} }}^{2} + \left( {\bar{n} - 1} \right)\left( {\sigma_{{l_{I} }}^{2} + \sigma_{{e_{I} }}^{2} } \right) + \sigma_{{e_{D} }}^{2}\)
\(\sigma_{p}^{2}\)	\(\sigma_{{a_{D} }}^{2} + \sigma_{env}^{2}\)	\(\sigma_{{a_{D} }}^{2} + \left( {\bar{n} - 1} \right)\sigma_{{a_{I} }}^{2} + r\left( {\bar{n} - 1} \right)\left( {2\sigma_{{a_{D,I} }} + \left( {\bar{n} - 2} \right)\sigma_{{a_{I} }}^{2} } \right) + \sigma_{env}^{2}\)
\(h^{2}\)	\(\sigma_{{a_{D} }}^{2} *\left[ {\sigma_{p}^{2} } \right]^{ - 1}\)
\(T^{2}\)	None	\(\sigma_{TBV}^{2} *\left[ {\sigma_{p}^{2} } \right]^{ - 1}\)

\(\sigma _{\text{TBV}}^{2}\), total heritable variance.\(\sigma_{{{\text{a}}_{\text{D}} }}^{2}\), direct genetic variance. \(\bar{n}\), average group size at test start (9.57 pigs). \(\sigma _{{{\text{a}}_{{{\text{I}},{\text{D}}}} }}\), direct–indirect genetic covariance. \(\sigma _{{{\text{a}}_{\text{I}} }}^{2}\), indirect genetic variance. \(\sigma_{\text{u}}^{2}\), sex-year-month variance. \(\sigma _{{{\text{l}}_{\text{D}} }}^{2}\), direct litter variance. \(\sigma _{{{\text{l}}_{\text{I}} }}^{2}\), indirect litter variance. \(\sigma _{\text{e} _\text{I}}^{2}\), Indirect animal variance. \(\sigma_{{{\text{e}}_{\text{D}} }}^{2}\), residual variance. \(r\), average relatedness among animals in a pen, averaged across pens (16.6%). \(\sigma _{\text{env}}^{2}\), total variance due to not-heritable variance components. \(\sigma _{\text{P}}^{2}\): total phenotypic variance. \({\text{h}}^{2}\), direct heritability. \({\text{T}}^{2}\), total heritability

ISSN: 1297-9686