Resumo

VAN DER WESTHUIZEN, R.R.; VAN DER WESTHUIZEN, J.  e  SCHOEMAN, S.J.. Genetic relationship between feed efficiency and profitability traits in beef cattle. S. Afr. j. anim. sci. [online]. 2004, vol.34, n.4, pp.50-52. ISSN 2221-4062.

Genetic selection to improve feed efficiency aims to reduce the cost of feeding costs in beef cattle production and thereby improve profitability. The aim of this study was to estimate genetic (co)variances to compare residual feed intake (RFI) and feed conversion ratio (FCR) with growth, reproductive and profitability traits measured in growth tests of young bulls. The heritability estimated for FCR was 0.34 and for RFI 0.31 with a genetic correlation estimate of 0.75 between the traits. The estimated genetic correlation between profitability and FCR and RFI were -0.92 and -0.59, respectively. The genetic correlations and expected correlated responses between RFI and FCR with post-wean profitability (M-value) suggest that indirect selection for M-value through the direct selection for FCR and/or RFI will result in slower genetic progress in M-value than direct selection for M-value. However, where the M-value cannot be calculated and/or direct selection for M-value is not possible, it would be better to select indirectly for M-value through the use of FCR rather than RFI.

Palavras-chave : Feed conversion ratio; genetic (co)variances; profitability; residual feed intake.

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