in which Gd and Gs are the genetic variance and covariance matrices of the 4 mortality causes related to the dam and sire genetic effect, U and R are the environmental variance and covariance matrices of the 4 mortality causes related to the permanent dam effects and the residual effects, I is the identity matrix, and A is the additive genetic relationship matrix. To obtain convergence, the variances and covariances in R were set to be 0.