Genetic relationships between yield and type traits were investigated using multiple-trait REML procedures with an animal model. Computing strategies were developed to deal with large populations and numbers of traits. Data consisted of records for 3 production and 15 type traits for 20,836 primiparous cows from 1982 to 1988. The model included 2358 herd management effects, 28,749 animal effects, and 23 groups for unknown parents. (Co)variance components were estimated using a canonical transformation with an accelerated expectation-maximization REML algorithm. Direct inversion of the coefficient matrix and solution to the transformed single-trait equations were by a sparse matrix solver.
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Misztal et al. (1992) studied this question.