Genetic correlations among sex-limited traits in beef cattle

Data from a comprehensive germ plasm evaluation program were used to estimate genetic correlations of reproductive and maternal traits of beef females with growth and carcass traits of their steer paternal half-sibs. The data set consisted of 187 sires with approximately four female and five male progeny each. Heritability estimates for age at puberty, weight at puberty, conceptions/service, gestation length, calving difficulty, progeny birth weight, progeny preweaning daily gain and mature weight measured on females were .613 +/- .177, .700 +/- .114, .026 +/- .126, .298 +/- .175, .217 +/- .175, .374 +/- .174, .094 +/- .161, and .540 +/- .150, respectively. Postweaning daily gain, carcass weight, fat trim weight and retail product weight measured on male half-sibs had estimated heritabilities of .363 +/- .090, .441 +/- .093, .502 +/- .093 and .451 +/- .093, respectively. The estimated genetic correlations suggest that selection for postweaning daily gain would result in increased age and weight at puberty, increased mature weight, improved fertility, reduced maternal gestation length, reduced maternal calving difficulty, increased maternal birth weight and reduced maternal preweaning gain. Predicted correlated responses to selection for reduced fat trim at a constant age were increased age and weight at puberty, increased mature weight, reduced maternal fertility, reduced maternal preweaning gain and increased maternal gestation length, birth weight and calving difficulty. Consequences of selection for increased age constant retail product weight or carcass weight appear to be increased age and weight at puberty, increased mature weight, improved fertility, increased maternal gestation length and maternal birth weight but reduced maternal difficulty and reduced maternal preweaning gain.