Example 4

Data for scan records taken on heifers in a single, large herd; 
4 traits;
simple animal model with  multiple fixed effects and covariables

A: full rank analysis

B: reduced rank analysis, fitting the first 2 PCs only

C: as B, but using the EM algorithm

D: univariate analysis, fitting paternal imprinting a additional RE

E: illustrates pooling of estimates from all possible (six) bivariate
   analyses using penalized maximum likelihood
