TAILIEUCHUNG - Báo cáo khoa hoc:"Genetic improvement of laying hens viability using survival analysis"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Genetic improvement of laying hens viability using survival analysis | Genet. Sel. Evol. 32 2000 23-40 INRA EDP Sciences 23 Original article Genetic improvement of laying hens viability using survival analysis Vincent DucROCQa Badi BESBESb Michel Protaisc a Institut national de la recherche agronomique Station de génétique quantitative et appliquée 78352 Jouy-en-Josas Cedex France b Hubbard-ISA Centre de Sélection BP 27 35220 Chateaubourg France c Hubbard-ISA Le Foeil 22800 Quintin France Received 26 May 1999 accepted 22 November 1999 Abstract - The survival of about eight generations of a large strain of laying hens was analysed separating the rearing period RP from the production period PP after hens were housed. For RP respectively pP resp. of the 109 160 resp. 100 665 female records were censored after 106 days resp. 313 days on the average. A Cox proportional hazards model stratified by flock season and including a hatch-within-flock HWF fixed effect seemed to reasonably fit the RP data. For PP this model could be further simplified to a non-stratified Weibull model. The extension of these models to sire-dam frailty mixed models permitted the estimation of the sire genetic variances at and for RP and PP respectively. Heritabilities on the log scale were equal to and . Nonadditive genetic effects could not be detected. Selection was simulated by evaluating all sires and dams after excluding all records from the last generation. Then actual parents of this last generation were distributed into four groups according to their own pedigree index. Raw survivor curves of the progeny of extreme parental groups substantially differed . by at 300 days for PP suggesting that selection based on solutions from the frailty models could be efficient despite the very large proportion of censored records. survival analysis viability laying hens selection Résumé Amelioration génétique de la viabilité des poules pondeuses à partir d une analyse de survie. Les données de survie d environ huit .

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