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Effect of Ignoring Random Sire and Dam Effects on Estimates and Standard Errors of Breed Comparisons

机译:忽略随机公顷和大坝效应对品种比较估算和标准误差的影响

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摘要

Data were weights of F1 calves and weaning weights of top-cross progeny from sires and maternal grandsires of 13 breeds. Three analyses were performed on each trait to obtain estimates and standard errors of breed effects needed to calculate across-breed EPD and accuracies. Model (R) for records of F1 progeny contained fixed effects for birth year and date of birth, sex, age and breed of dam, and breed of sire, and a random residual effect. The second analysis included random effects for sires (RS), and the third analysis included random effects for sires and dams (RSD). In maternal analysis of top-cross progeny, model (Rm) contained fixed effects for cycle of experiment, age of dam, year of birth, sex, breeds of maternal grandam and grandsire, and breed of sire, and a random residual effect. In addition, the second and third analyses fit random effects for maternal grandsires (RSm) and for maternal grandsires and daughters of maternal grandsires (RSDm) . Estimates of breed of sire effects changed only slightly for different models. Total variance increased in RSD and RS relative to R. Standard errors of breed of sire comparisons were underestimated with Model R, compared to Models RS and RSD. Standard errors of other contrasts were generally not affected. Variance components, breed effects, and standard errors followed patterns for Rm, RSm , and RSDm similar to those for R, RS, and RSD. Ignoring random variation due to sires and dams underestimated standard errors of breed of sire comparisons.
机译:数据是来自13个品种的父本和后代的F1小牛体重和断交后代体重。对每个性状进行了三种分析,以获得计算跨品种EPD和准确性所需的品种效应的估计值和标准误。 F1子代记录的模型(R)包含出生年份和出生日期,性别,年龄和水坝品种,父代品种的固定效应,以及随机残留效应。第二项分析包括公羊的随机效应(RS),第三项分析包括母马和大坝的随机效应(RSD)。在对顶级杂交后代的母体分析中,模型(Rm)包含实验周期,水坝年龄,出生年份,性别,祖母和祖父母的品种以及父代的品种的固定效应,以及随机残留效应。另外,第二和第三分析适合于母亲祖辈(RSm)以及母亲祖辈和母亲祖辈的女儿的随机效应。对于不同模型,父亲效应的品种估计仅略有变化。相对于R,RSD和RS的总方差增加。与RS和RSD相比,使用R模型低估了父系比较品种的标准误差。其他对比的标准误差通常不受影响。方差成分,品种效应和标准误差遵循的Rm,RSm和RSDm模式与R,RS和RSD相似。忽略由于父本和母本引起的随机变化,低估了父本比较品种的标准误差。

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