Multitrait estimation of direct and maternal (co)variances for growth and efficiency traits in a multibreed beef cattle herd
CITATION: Schoeman, S. J. & Jordaan, G. F. 1999. Multitrait estimation of direct and maternal (co)variances for growth and efficiency traits in a multibreed beef cattle herd. South African Journal of Animal Science, 29(3):124-136.
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Estimates of (co)variance components were obtained for growth and efficiency traits in a multibreed synthetic beef cattle herd. Components were estimated simultaneously by fitting four alternative seven-trait models. Direct heritabilities varied according to the model fitted but were higher for preweaning than for postweaning traits. Applying a model which also included maternal heritabilities, the direct-maternal covariance and the permanent environmental effect, direct heritabilities of weaning weight, weaning index, preweaning Kleiber ratio, preweaning relative growth rate, cow efficiency, postweaning Kleiber ratio and postweaning relative growth rate were 0.57, 0.40, 0.35, 0.71, 0.54, 0.16 and 0.13, respectively. In general, maternal heritabilities varied from 0.03 for postweaning Kleiber ratio to 0.45 for cow efficiency. Direct-maternal correlations were negative and varied from -0.31 to -0.58 for weaning weight related traits, but was -0.77 for cow efficiency.