Schnyder U, Hofer A, Labroue F, Künzi N
Institute of Animal Science, Swiss Federal Institute of Technology (ETH), 8092 Zurich, Switzerland.
Genet Sel Evol. 2001 Nov-Dec;33(6):635-58. doi: 10.1186/1297-9686-33-6-635.
Daily feed intake data of 1 279 French Landrace (FL, 1 039 boars and 240 castrates) and 2 417 Large White (LW, 2 032 boars and 385 castrates) growing pigs were recorded with electronic feed dispensers in three French central testing stations from 1992-1994. Male (35 to 95 kg live body weight) or castrated (100 kg live body weight) group housed, ad libitum fed pigs were performance tested. A quadratic polynomial in days on test with fixed regressions for sex and batch, random regressions for additive genetic, pen, litter and individual permanent environmental effects was used, with two different models for the residual variance: constant in model 1 and modelled with a quadratic polynomial depending on the day on test d(m) as follows in model 2: sigma(epsilon(m))(2) = exp (gamma(0) + gamma(1) d(m) + gamma(2) d(m)(2)). Variance components were estimated from weekly means of daily feed intake by means of a Bayesian analysis using Gibbs sampling. Posterior means of (co)variances were calculated using 800 000 samples from four chains (200 000 each). Heritability estimates of regression coefficients were 0.30 (FL model 1), 0.21 (FL model 2), 0.14 (LW1) and 0.14 (LW2) for the intercept, 0.04 (FL1), 0.04 (FL2), 0.11 (LW1) and 0.06 (LW2) for the linear, 0.03 (FL1), 0.04 (FL2) 0.11 (LW1) and 0.06 (LW2) for the quadratic term. Heritability estimates for weekly means of daily feed intake were the lowest in week 4 (FL1: 0.11, FL2: 0.11) and week 1 (LW1: 0.09, LW2: 0.10), and the highest in week 11 (FL1: 0.25, FL2: 0.24) and week 8 (LW1: 0.19, LW2: 0.18), respectively. Genetic eigenfunctions revealed that altering the shape of the feed intake curve by selection is difficult.
1992年至1994年期间，在法国的三个中央测试站，使用电子饲料分配器记录了1279头法国长白猪（FL，1039头公猪和240头阉割猪）和2417头大白猪（LW，2032头公猪和385头阉割猪）生长猪的每日采食量数据。对公猪（活体体重35至95千克）或阉割猪（活体体重100千克）进行群体饲养，自由采食，并进行性能测试。使用了一个关于测试天数的二次多项式，其中性别和批次为固定回归，加性遗传、栏舍、窝和个体永久环境效应为随机回归，残差方差有两种不同模型：模型1中为常数，模型2中根据测试天数d(m)用二次多项式建模，如下所示：sigma(epsilon(m))(2) = exp (gamma(0) + gamma(1) d(m) + gamma(2) d(m)(2))。通过使用吉布斯采样的贝叶斯分析，从每日采食量的每周平均值估计方差成分。使用来自四条链（每条链200000个）的800000个样本计算（协）方差的后验均值。对于截距，回归系数的遗传力估计值分别为0.30（FL模型1）、0.21（FL模型2）、0.14（LW1）和0.14（LW2）；对于线性项，分别为0.04（FL1）、0.04（FL2）、0.11（LW1）和0.06（LW2）；对于二次项，分别为0.03（FL1）、0.04（FL2）、0.11（LW1）和0.06（LW2）。每日采食量每周平均值的遗传力估计值在第4周（FL1：0.11，FL2：0.11）和第1周（LW1：0.09，LW2：0.10）最低，在第11周（FL1：0.25，FL2：0.24）和第8周（LW1：0.19，LW2：0.18）最高。遗传特征函数表明，通过选择改变采食量曲线的形状很困难。
