where y is a vector of phenotypes, b is a vector of the fixed effects (slaughter year, NCAPG I442M genotype), u is the vector of individual infinitesimal polygenic effects, g is a vector of the additive QTL effects not fixed within founder breeds; F, Z and Q represent the incidence matrices for the fixed, polygenic and the QTL effect, respectively, and e is the vector of random residuals.