A common way to make up a selection index is using variance- covariance matrices.(S.R.Searle, 1966.) P b - G a where, P is the variance-covariance matrix of phenotypes, G is the variance-covariance natrix of genotypes, a is the matrix of economic value and b is the matrix of weight factores need to be solved. It is necessary to estimate parameters like standard deviation and heritabllity for each trait, phenotypic and genetic correlations between every two traits. The procedure of working out such an index is still rather complex.\

}, keywords = {indexes, livestock, selection}, author = {Wu, C.} }