Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Multiple trait model combining random regressions for daily feed intake with single measured performance traits of growing pigs | 61 Genet Sei. Evol. 34 2002 61-81 INRA EDP Sciences 2002 DOI gse 2001004 Original article Multiple trait model combining random regressions for daily feed intake with single measured performance traits of growing pigs Urs Schnydera Andreas Hofera Florence Labroueb Niklaus Kunzia a Institute of Animal Science Swiss Federal Institute of TechnologY ETH 8092 Zurich Switzerland b Institut technique du pore La Motte au Vicomte BP 3 35651 Le Rheu cedex France Received 14 September 2000 accepted 21 June 2001 Abstract - a random regression model for daily feed intake and a conventional multiple trait animal model for the four traits average daily gain on test ADG feed conversion ratio FCR carcass lean content and meat quality index were combined to analyse data from 1449 castrated male Large White pigs performance tested in two French central testing stations in 1997. Group housed pigs fed ad libitum with electronic feed dispensers were tested from 35 to 100 kg live body weight. A quadratic polynomial in days on test was used as a regression function for weekly means of daily feed intake and to describe its residual variance. The same fixed batch and random additive genetic pen and individual permanent environmental effects were used for regression coefficients of feed intake and single measured traits. Variance components were estimated by means of a Bayesian analysis using Gibbs sampling. Four Gibbs chains were run for 550000 rounds each from which 50000 rounds were discarded from the burn-in period. Estimates of posterior means of covariance matrices were calculated from the remaining two million samples. Low heritabilities of linear and quadratic regression coefficients and their unfavourable genetic correlations with other performance traits reveal that altering the shape of the feed intake curve by direct or indirect selection is difficult. random regression variance component Gibbs sampling feed intake pig Correspondence and reprints E-mail .
