tailieunhanh - Báo cáo khoa hoc:" Gunnar Klemetsdal inbreeding on racing performance Norwegian cold-blooded trotters"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: " Gunnar Klemetsdal inbreeding on racing performance Norwegian cold-blooded trotters | Genet. Sei. Evol. 30 1998 351-366 Inra Elsevier Paris 351 Original article The effect of inbreeding . on racing performance in Norwegian cold-blooded trotters Gunnar Klemetsdal Department of Animal Science Agricultural University of Norway Box 5025 1432 Aas-NLH Norway Received 28 November 1997 accepted 8 June 1998 Abstract - The effect of inbreeding . the inbreeding coefficient on racing performance as measured by accumulated transformed and standardised earnings ATSE was estimated either by linear or curvilinear regression one variable at a time in univariate animal models. The statistical model included in addition the effects of sex and birth year. Four ATSE variables with information on earnings summed up over age-classes 3 3-4 3-5 and 3-6 years of age were analysed. Only performances for horses born from 1972 onwards were used. For each animal five inbreeding variables were calculated utilising ancestors for two F2 three F3 four F4 and five F5 generations or all available pedigree information FTOT . Number of records used in analyses of ATSE3 ATSE3-4 ATSE3-5 and ATSE3-6 were 7 866 7866 6 825 and 5 907 respectively. The estimated regressions transformed to the standardised normal scale were negative showing that racing performance was depressed by inbreeding. The best fit was for curvilinear regression. The pattern made up by the estimated regression coefficients indicated that selection was able to arrest some inbreeding depression over the first four generations most likely due to recessive mutations while additional purging of assumed mildly recessive mutations was shown to be a slower process. Inra Elsevier Paris horse I inbreeding depression I selection Resume Effet de la consanguinité sur les performances en course chez les trotteurs Norvégiens. L effet du coefficient de consanguinité sur les performances en course mesurées par les gains cumulés transformes et standardises ATSE a été estimé par regression linéaire OU curvilinéaire variable par variable