Issue |
Genet. Sel. Evol.
Volume 34, Number 1, January-February 2002
|
|
---|---|---|
Page(s) | 61 - 81 | |
DOI | https://doi.org/10.1051/gse:2001004 |
Genet. Sel. Evol. 34 (2002) 61-81
DOI: 10.1051/gse:2001004
Multiple trait model combining random regressions for daily feed intake with single measured performance traits of growing pigs
Urs Schnydera, Andreas Hofera, Florence Labroueb and Niklaus Künziaa Institute of Animal Science, Swiss Federal Institute of Technology (ETH), 8092 Zürich, Switzerland
b Institut technique du porc, 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 1 449 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
550 000 rounds each, from which 50 000 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.
Key words: random regression / variance component / Gibbs sampling / feed intake / pig
Correspondence and reprints: Urs Schnyder
e-mail: urs.schnyder@braunvieh.ch
© INRA, EDP Sciences 2002