Chen C Y, Johnson R K, Newman S, Kachman S D, Van Vleck L D
Department of Animal Science, University of Nebraska, Lincoln 68583-0908, USA.
J Anim Sci. 2009 Mar;87(3):844-9. doi: 10.2527/jas.2008-0937. Epub 2008 Nov 7.
Effects of social interactions on responses to selection for ADG were examined with records of 9,720 boars from dam lines (1 and 2) and sire lines (3 and 4) provided by Pig Improvement Company. Each line was analyzed separately. Pens contained 15 boars. Average daily gains were measured from about 71 to 161 d of age and BW from 31 to 120 kg. Models included fixed effects of contemporary groups and initial test age as a covariate and random direct genetic (a), social genetic (c), social environmental (ce), and litter (lt) effects. Estimates of direct heritability with model 1 (the full model with a, c, ce, and lt) were 0.21, 0.28, 0.13, and 0.15 for lines 1 to 4. Estimates of heritability of social effects were near zero. Estimates of total heritable variance were 55, 52, 38, and 96% of phenotypic variance for lines 1 through 4. Empirical responses to selection with model 1 were calculated using the parameter estimates from model 1. For response of 1 genetic SD for both components (a and c), the proportions of expected total gain due to social effects (with economic weights of 1 and pen size-1 = 14) were 54, 28, 65, and 65% for the 4 lines. Genetic superiorities of the top 10% of boars were calculated for boars ranked using reduced models, but with EBV calculated using the full model (model 1). Average total breeding values (ETBV = EBV(a)+14EBV(c)) for the top 10% of boars selected with model 1 were 74.08, 94.26, 31.79, and 92.88 g for lines 1 through 4, respectively. For rankings based on model 2 (a, ce, and lt), but EBV calculated with model 1, average total breeding values for the top 10% were 68.15, 94.03, 7.33, and 84.72 g with empirical correlated responses for genetic social effects from selection for direct effects of 0.93, 1.89, -2.19, and 3.52 g for lines 1 to 4.
利用养猪改良公司提供的来自母系（1系和2系）和父系（3系和4系）的9720头公猪的记录，研究了社会互动对平均日增重（ADG）选择反应的影响。每个系分别进行分析。每个栏舍饲养15头公猪。在大约71至161日龄测量平均日增重，在31至120千克体重阶段测量体重（BW）。模型包括当代组的固定效应和初始测试年龄作为协变量，以及随机的直接遗传效应（a）、社会遗传效应（c）、社会环境效应（ce）和窝效应（lt）。对于1至4系，模型1（包含a、c、ce和lt的完整模型）的直接遗传力估计值分别为0.21、0.28、0.13和0.15。社会效应的遗传力估计值接近零。对于1至4系，总遗传方差估计值分别为表型方差的55%、52%、38%和96%。使用模型1的参数估计值计算模型1的选择实证反应。对于两个组成部分（a和c）的1个遗传标准差的反应，对于4个系，由于社会效应导致的预期总增重比例（经济权重为1且栏舍大小 - 1 = 14）分别为54%、28%、65%和65%。对于使用简化模型排名但使用完整模型（模型1）计算估计育种值（EBV）的公猪，计算了前10%公猪的遗传优势。对于用模型1选择的前10%公猪，1至4系的平均总育种值（ETBV = EBV(a)+14EBV(c)）分别为74.08、94.26、31.79和92.88克。对于基于模型2（a、ce和lt）排名但用模型1计算EBV的情况，前10%公猪的平均总育种值分别为68.15、94.03、7.33和84.72克，1至4系因直接效应选择产生的遗传社会效应的实证相关反应分别为0.93、1.89、 - 2.19和3.52克。
