Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Estimation of genetic parameters of egg production traits of laying hens by restricted maximum likelihood applied to a multiple-trait reduced animal model | Genet Sei Evol 1992 24 539-552 Elsevier INRA 539 Original article Estimation of genetic parameters of egg production traits of laying hens by restricted maximum likelihood applied to a multiple-trait reduced animal model B Besbes4 V Ducrocq1 JL Foulley1 M Protais4 A Tavernier1 M Tixier-Boichard2 c Beaumont3 1 INRA Station de Génétique Quantitative et Appliquée Centre de Recherche de Jouy-en-Josas 78352 Jouy-en-Josas Cedex 2 INRA Laboratoire de Génétique Factorielle 78352 Jouy-en-Josas Cedex 3 INRA Station de Recherches Avicoles 37380 Monnaie 4 Institut de Selection Animale Établissements de Le Foeil 22800 Quintin France Received 18 December 1991 accepted 30 June 1992 Summary - Variance components for egg production traits No of eggs produced between 19 and 26 26 and 38 and 26 and 54 wk of age egg characteristics average egg weight at 2 different ages and egg density and body weight of hens at 40 wk of age were estimated in two strains of a breeding company by univariate and multivariate Restricted Maximum Likelihood REML applied to a Reduced Animal Model RAM . To allow tridiagonalization of the coefficient matrix when RAM is considered the approach of Thompson and Meyer 1990 using an imaginary random effect with negative variance was implemented. Canonical transformation was also employed. REML estimation carried out on 15 random samples of w 7 000 recorded hens drawn from each of 2 data files corresponding to 2 different strains showed a rather small genetic antagonism between the group of egg production traits and egg density on one hand and that of egg weights on the other hand. Weight of hens behaved differently in the 2 strains. It showed also that traits within these groups were positively correlated. Heritabilities obtained by univariate and multivariate analyses were very similar and were lower for egg production traits from to than for egg characteristics or weight of hens from to . egg production genetic parameter restricted maximum .
