tailieunhanh - Báo cáo sinh học: "Expected efficiency of selection for growth in a French beef cattle breeding scheme. II. Prediction of asymptotic genetic gain in a heterogeneous population"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Expected efficiency of selection for growth in a French beef cattle breeding scheme. II. Prediction of asymptotic genetic gain in a heterogeneous population | Genet Sei Evol 1995 27 171-188 Elsevier INRA 171 Original article Expected efficiency of selection for growth in a French beef cattle breeding scheme. II. Prediction of asymptotic genetic gain in a heterogeneous population F Phocas JJ Colleau F Ménissier Institut national de la recherche agronomique station de génétique quantitative et appliquée 78352 Jouy-en-Josas cedex France Received 24 February 1994 accepted 18 October 1994 Summary - Asymptotic genetic gains and lags are derived in French beef cattle breeding schemes for an objective including direct and maternal effects on growth. A simple general method using matrix algebra is presented to simultaneously calculate asymptotic genetic gains and lags whatever the population structure. The heterogeneity of use of artificial insemination Al in selection herds is considered. At the same overall rate of Al use larger asymptotic genetic gains can be obtained by concentrating Al in only a fraction of the herds instead of keeping the same lower rate in all herds. An application concerns the Limousin selection nucleus where 23 of calves are bred by Al in only 50 of the herds. When an aggregate breeding objective for growth is considered positive annual asymptotic genetic gains are expected in both direct genetic standard deviation and maternal effects genetic standard deviation on growth despite the negative estimates around of genetic direct-maternal correlations. The major part of the genetic gains in direct and maternal effects are due to Al sire selection and dam selection respectively. Taking into account sampling uncertainty in estimates of preweaning genetic parameters leads to the conclusion that the predicted asymptotic response in maternal effects is positive with a very high probability. Nevertheless strongly negative around estimates of correlations between direct and maternal effects lead to negative responses in maternal effects. beef cattle growth asymptotic genetic gain open nucleus .