König S, Simianer H, Willam A
Institute of Animal Breeding and Genetics, University of Göttingen, 37075 Göttingen, Germany.
J Dairy Sci. 2009 Jan;92(1):382-91. doi: 10.3168/jds.2008-1310.
The objective of this study was to compare a conventional dairy cattle breeding program characterized by a progeny testing scheme with different scenarios of genomic breeding programs. The ultimate economic evaluation criterion was discounted profit reflecting discounted returns minus discounted costs per cow in a balanced breeding goal of production and functionality. A deterministic approach mainly based on the gene flow method and selection index calculations was used to model a conventional progeny testing program and different scenarios of genomic breeding programs. As a novel idea, the modeling of the genomic breeding program accounted for the proportion of farmers waiting for daughter records of genotyped young bulls before using them for artificial insemination. Technical and biological coefficients for modeling were chosen to correspond to a German breeding organization. The conventional breeding program for 50 test bulls per year within a population of 100,000 cows served as a base scenario. Scenarios of genomic breeding programs considered the variation of costs for genotyping, selection intensity of cow sires, proportion of farmers waiting for daughter records of genotyped young bulls, and different accuracies of genomic indices for bulls and cows. Given that the accuracies of genomic indices are greater than 0.70, a distinct economic advantage was found for all scenarios of genomic breeding programs up to factor 2.59, mainly due to the reduction in generation intervals. Costs for genotyping were negligible when focusing on a population-wide perspective and considering additional costs for herdbook registration, milk recording, or keeping of bulls, especially if there is no need for yearly recalculation of effects of single nucleotide polymorphisms. Genomic breeding programs generated a higher discounted profit than a conventional progeny testing program for all scenarios where at least 20% of the inseminations were done by genotyped young bulls without daughter records. Evaluation of levels of annual genetic gain for individual traits revealed the same potential for low heritable traits (h(2) = 0.05) compared with moderate heritable traits (h(2) = 0.30), preconditioning highly accurate genomic indices of 0.90. The final economic success of genomic breeding programs strongly depends on the complete abdication of any forms of progeny testing to reduce costs and generation intervals, but such a strategy implies the willingness of the participating milk producers.
本研究的目的是将以后裔测定方案为特征的传统奶牛育种计划与基因组育种计划的不同方案进行比较。最终的经济评估标准是贴现利润，它反映了在生产和功能的平衡育种目标下，每头奶牛的贴现回报减去贴现成本。一种主要基于基因流动方法和选择指数计算的确定性方法被用于模拟传统的后裔测定计划和基因组育种计划的不同方案。作为一个新颖的想法，基因组育种计划的建模考虑了在将基因分型的青年公牛用于人工授精之前等待其女儿记录的农户比例。为了与德国的一个育种组织相对应，选择了用于建模的技术和生物学系数。在一个拥有100,000头奶牛的群体中，每年对50头测试公牛进行的传统育种计划作为基础方案。基因组育种计划的方案考虑了基因分型成本的变化、母牛父亲的选择强度、等待基因分型青年公牛女儿记录的农户比例，以及公牛和母牛基因组指数的不同准确性。鉴于基因组指数的准确性大于0.70，发现基因组育种计划的所有方案都有明显的经济优势，优势系数高达2.59，这主要归因于世代间隔的缩短。当从全群体的角度来看，并考虑到系谱登记、产奶记录或饲养公牛的额外成本时，基因分型成本可以忽略不计，特别是如果不需要每年重新计算单核苷酸多态性的效应。在所有至少20%的人工授精是由没有女儿记录的基因分型青年公牛完成的方案中，基因组育种计划产生的贴现利润高于传统的后裔测定计划。对各个性状的年度遗传进展水平的评估表明，与中等遗传力性状（h² = 0.30）相比，低遗传力性状（h² = 0.05）具有相同的潜力，前提是基因组指数的高度准确性为0.90。基因组育种计划最终的经济成功在很大程度上取决于完全放弃任何形式的后裔测定以降低成本和世代间隔，但这样的策略意味着参与的奶农要有意愿。
