TAILIEUCHUNG - Báo cáo sinh học: " Impact of the use of bovine somatotropin (BST) on dairy cattle selection"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Impact of the use of bovine somatotropin (BST) on dairy cattle selection | 479 Genet. Sei. Evol. 1989 21 479-491 Elsevier INRA Original article Impact of the use of bovine somatotropin BST on dairy cattle selection . Colleau Institut National de la Recherche Agronomique Station de Génétique quantitative et appliquée 78350 Jouy-en-Josas France. received 27 October 1988 accepted 15 June 1989 Summary - A very simple breeding scheme for milk yield was generated by a MonteCarlo method in order to evaluate the potential impact of bovine somatotropin BST on genetic gains and on the discrepancies between true and estimated breeding values. The parameters were treatment rate 10 30 50 reporting complete or random BST allocation system random best or worst cows data correction system none conventional BLUP or bivariate BLUP and some dispersion parameters of the additional yield provided by BST. Given that there were no herd effects and no embryo transfer the range of the decrease for genetic gains was 1-10 not fully explained by the decrease in selection accuracy and was relatively well balanced between the male and female gene transmission paths. The perception of this situation is difficult especially when BST is allocated to the best cows because very large biases in the evaluation may occur up to 30 of the true selection differentials . These biases occur even when reporting is complete and when a conventional BLUP is implemented. This problem disappears when a multi-trait BLUP is applied after completely discarding the treated parts of lactation. In this case losses of genetic gains are relatively moderate as well. Possible herd effects were ignored in the simulation process to give the opportunity of correct calculations for selection accuracies. This artificial prerequisite should be removed in further studies. cattle selection - milk yield - bovine somatotropin - genetic gain Resume Impact de 1 utilisation de la somatotropine bovine BST sur les programmes bovins de selection laitière. On a simulé de manière aléatoire le fonction-nement d

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