Wallén S E, Lillehammer M, Meuwissen T H E
Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, PO Box 5003, 1432 Ås, Norway.
Nofima, PO Box 5010, 1432 Ås, Norway.
J Dairy Sci. 2017 Aug;100(8):6327-6336. doi: 10.3168/jds.2016-11458. Epub 2017 Jun 7.
Alternative genomic selection and traditional BLUP breeding schemes were compared for the genetic improvement of feed efficiency in simulated Norwegian Red dairy cattle populations. The change in genetic gain over time and achievable selection accuracy were studied for milk yield and residual feed intake, as a measure of feed efficiency. When including feed efficiency in genomic BLUP schemes, it was possible to achieve high selection accuracies for genomic selection, and all genomic BLUP schemes gave better genetic gain for feed efficiency than BLUP using a pedigree relationship matrix. However, introducing a second trait in the breeding goal caused a reduction in the genetic gain for milk yield. When using contracted test herds with genotyped and feed efficiency recorded cows as a reference population, adding an additional 4,000 new heifers per year to the reference population gave accuracies that were comparable to a male reference population that used progeny testing with 250 daughters per sire. When the test herd consisted of 500 or 1,000 cows, lower genetic gain was found than using progeny test records to update the reference population. It was concluded that to improve difficult to record traits, the use of contracted test herds that had additional recording (e.g., measurements required to calculate feed efficiency) is a viable option, possibly through international collaborations.
在模拟的挪威红牛奶牛群体中，比较了替代基因组选择和传统最佳线性无偏预测（BLUP）育种方案对饲料效率的遗传改良效果。研究了产奶量和残余饲料摄入量随时间的遗传进展变化以及可实现的选择准确性，以此作为饲料效率的衡量指标。在基因组BLUP方案中纳入饲料效率时，基因组选择能够实现较高的选择准确性，并且所有基因组BLUP方案在饲料效率方面的遗传进展均优于使用系谱关系矩阵的BLUP方案。然而，在育种目标中引入第二个性状会导致产奶量的遗传进展降低。当使用对母牛进行基因分型并记录饲料效率的合同测试牛群作为参考群体时，每年向参考群体中额外添加4000头新的小母牛所获得的准确性，与使用每个公牛250头女儿进行后裔测定的雄性参考群体相当。当测试牛群由500头或1000头牛组成时，发现其遗传进展低于使用后裔测定记录来更新参考群体的情况。得出的结论是，为了改良难以记录的性状，使用具有额外记录（例如计算饲料效率所需的测量值）的合同测试牛群是一种可行的选择，可能需要通过国际合作来实现。
