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In this study a total of 6499 records were obtained for fibre diameter (FD) and coefficient of variation of FD (CV), 3283 records for greasy fleece weight (GFW), staple length (SL) and shearing interval (SI) and 1802 records of textile value index (TV) obtained from an experimental herd of alpacas exploited in the Peruvian Altiplano.The estimated heritabilities were: 0.412 ± 0.015 (FD), 0.321 ± 0.013 (CV), 0.098 ± 0.016 (GFW), 0.070 ± 0.011 (SL), 0.061 ± 0.012 (SI) and 0.163 ± 0.017 (TV). No significant genetic correlation was found for the pairs FD-CV and CV-GFW whilst the pairs FD-GFW, FD-SI and FD-TV had significant genetic correlations of, respectively, 0.405 ± 0.081, − 0.395 ± 0.078 and − 0.746 ± 0.049. No significant correlations were found for SL except for the pair SL-SI (0.397 ± 0.099). The TV index also showed significant genetic correlations with CV of 0.125 ± 0.061 and with GFW of 0.490 ± 0.070. All estimates of permanent environmental effects (c2) associated with the six analysed traits were statistically significant ranging from 0.008 for SI to 0.259 for CV. Total repeatability for the analysed traits was low for SI (0.069) and SL (0.090), moderate for TV (0.299) and GFW (0.316) and high for FD (0.578) and CV (0.579). The permanent environmental effect associated with CV is significantly correlated with those of the other traits except for FD. The permanent environmental effects associated with GFW and SL seemed to be basically the same (estimated correlation of 0.916 ± 0.062). The permanent environmental effect for TV is highly correlated with those associated with GFW (0.498 ± 0.058) and SL (0.750 ± 0.137). Expected selection response for TV was higher when FD was considered as selection goal instead of TV itself.It would, therefore, be more efficient to use FD rather than empirical indices as selection criterion to increase textile value in Peruvian alpacas. The reported genetic parameters and correlation matrices can be useful to implement multitrait breeding value estimations for alpaca selection. 相似文献
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H. N. Erb A. J. Heinrichs R. E. Woods W. M. Sischo 《Preventive veterinary medicine》1996,25(3-4):291-300
We did a test-retest study on 21 farms to assess the repeatability of the Dairy Heifer Health Report of the National Dairy Heifer Evaluation Project. The median retest interval was 42 days (range 14–63 days), retest interviewers were blinded as to responses on the first visits, and all date-specific questions were anchored to the dates of the first tests. The overall discrepancy percentage was 8.5% (95% CI 8.0–9.0). Individual farms had discrepancy percentages of 3.0–15.2%; 240 out of the 539 questions had no discrepancies at all, but 81 questions had more than four (out of 21 possible) discrepancies (lowest percentages among the 81: 24%; 95% lower confidence limit on 24%: 6%). Combining ‘no’ and ‘not applicable’ responses for six similarly worded questions in the Biosecurity section would reduce the overall questionnaire discrepancy percentage to 7.8% and would bring that section's discrepancy percentage down to 8.6%. The other discrepancy percentages by section were: Maternity Hygiene, 14.1 %; Preweaning Hygiene, 4.8%; Disease Agents, 3.6%; Vaccination Practices, 12.1%; Preventive Practices, 16.8%. Discrepancy percentages did not differ importantly by type of question (independent, filter, or subordinate) or by type of response required (categorical, count, or measurement). Discrepancy percentages were independent of retest interviewer, test-retest interval and order of test within state (a proxy for time since training of the interviewers) but were correlated with herd size (rsp = 0.59). 相似文献
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油松种子园无性系球果性状选择指数的研究 总被引：6，自引：0，他引：6
１９８７￣１９９０年对卢氏油松种子园组成无性系作了球果分析，各以２２、１５、３１、３０个无性系为材料，估算了各球果性状的重复力、球果性状间的表型相关和遗传相关，进行了无性系球果性状选择指数的研究。结果表明，各球果性状均有很高的重复力，受强度遗传控制，球果性状间遗传相关系数和表型相关系数变化趋势基本一臻选择的可靠性大。球果单性状年度间秩次相关系数和遗传相关系数小，而选择指数年度间的秩次相关系数平均最 相似文献
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统计表明,德系安哥拉母兔平均产仔6.73头,仔兔断奶成活率82.39%。产仔力的重复力0.32,1～6胎次的平均产仔数非常接近,7胎以后明显下降。产仔力与母兔成年体重和年产毛量的相关系数极低,分别为0.265和0.114。随着产仔数增加,哺乳期仔兔死亡数也上升。笔者提出,母兔的平均产仔数以6～7.5头为适宜。 相似文献
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本文用概率论的方法导出了重复力估计值的概率分布密度函数。并对重复力假设检验和区间估计也进行了讨论。 相似文献
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This paper applies linear mixed model and pattern analyses to 122 on-farm trials of commercial and near-commercial sunflower (Helianthus annuus L.) hybrids grown over 15 years in 32 locations of central Argentina to determine the contributions of change in characteristics of germplasm pools to increases in oil yield. The ‘Relative Peak Performance’ (best linear unbiased predictors, BLUPs) of 49 hybrids released for the conventional market between 1983 and 2005 showed genetic gains of 11.9 kg ha−1 year−1, 0.19% year−1 and 16.1 kg ha−1 year−1 for oil yield, grain-oil concentration and grain yield, respectively. Oil yield improvement was consistent across three market segments and a biplot of genotype-by-attribute BLUPs summarised 20 years of breeding to demonstrate how the merging of two germplasm pools of differing maturity, achene type and grain-oil concentration resulted in step-wise improvements in grain yield and grain-oil concentration and a move toward an intermediate maturity. The analysis of general combining ability within a breeding program shows that the female and male germplasm pools were improved in different ways over time. On the female side, much of this improvement was to encompass different combinations of the determining traits of oil yield, while on the male side the improvement was more linear in terms of exploitation of genotypic variance for oil yield per se. 相似文献
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Membership, social relationships and dispersal were recorded for all members of one clan of spotted hyaenas, Crocuta crocuta, in the Kruger National Park over a period of 27 months. The clan comprised females, cubs, and three social classes of males: resident natal males, peripheral immigrant males and central immigrant males. Although a linear dominance hierarchy was recorded under all circumstances, it was most strongly expressed at food. Females were philopatric and maintained a network of amicable relationships with each other and their offspring. Social dominance assured them priority of access to carcasses, so that they obtained a high proportion of meat. Males left their natal clans and attempted to join neighbouring clans, where they were initially treated as territorial intruders, but could eventually gain membership albeit with low social status, lowest feeding priority at carcasses and precarious social relationships. An immigrant male that maintained close attendance on females became a central immigrant and gained unrivalled breeding status. The segregation of a clan into co-operative relatives and subordinate immigrants assures an optimal distribution of resources. 相似文献
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通过对银狐主要繁殖性状重复力的估计和分析,为选育和改良银狐提供理论基础。利用具有2次或2次以上产仔记录的248只母银狐627个繁殖成绩和51只公狐211个繁殖成绩记录,估计了银狐主要繁殖性状的重复力。产仔母狐胎平均产仔数、胎平均断奶活仔数、母狐配种日期、母狐妊娠期的重复力分别为0.114、0.007、0.270和0.206,公狐与配母狐平均产仔数、与配母狐平均断奶活仔数、与配母狐受胎率的重复力分别为0.108、0.303和0.206。母银狐繁殖能力和公狐与配母狐的平均产仔数、受胎率等性状主要受非遗传因素所控制。 相似文献
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