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Báo cáo sinh học: "Genetic parameters for twinning in the Maine-Anjou breed"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Genetic parameters for twinning in the Maine-Anjou breed | Genet Sei Evol 1991 23 421-430 Elsevier INRA 421 Original article Genetic parameters for twinning in the Maine-Anjou breed E Manfredi JL Foulley M San Cristobal p Gillard Instiiut National de la Recherche Agronomique Station de Génétique Quantitative et Appliquée 78352 Jouy-en-Josas Gedex France Received 8 March 1991 accepted 3 June 1991 Summary - Genetic parameters and bull transmitting abilities were estimated for twinning in the Maine-Anjou breed. Twin calving performance was analyzed as a threshold binary trait assuming direct and fetal effects and polygenic inheritance. The statistical model included the effects of parity year-season herd sire of the fetus sire of the cow and cow within sire. Heritabilities were 0.13 and 0.02 for direct and fetal effects respectively with a correlation between both effects of 0.36. Transmitting abilities of bulls were expressed on the underlying and observed scales the bull ranked first had an observed twinning rate of 13.7 among its 259 female progeny corresponding to an estimated breeding value of 2.6 units of underlying standard deviation or 13.9 as the probability for a future daughter to have a twin calving in her second parity. It is concluded that there is considerable place for twinning selection among Maine-Anjou bulls. cattle twinning genetic parameter sire evaluation threshold model Resume Paramètres génétiques de la gémellité en race Maine-Anjou. Cette étude vise à estimer les paramètres et les valeurs génétiques de la gémellité en race bovine Maine-Anjou. L analyse du taux de vêlages gémellaires a été effectuee en traitant ce caractère comme un caractère tout-ou-rien à seuil soumis à des effets directs et fcetaux en postulant une hérédité polygénique. Les facteurs de variation pris en compte étaient le rang de vêlage I interaction année X saison de vêlage le troupeau le père du foetus le père de la vache et la vache intra-père. Le coefficient d heritabilite a été estimé à 0 02 pour les effets fcetaux et 0 13 pour