ADSA-SAD Dairy Production Oral Competition

摘要

Before 2009 it required nearly 5 years before the genetic merit of an individualanimal was determined. Once genomics was introduced intonational evaluations, genetic progress in the dairy industry rapidly increased.The genetic merit of an animal can be determined at a youngage and is highly reliable due to the large reference population available.However, the majority of genetic gain has been achieved on the sireside, resulting in genetic lag of cows. One approach to increasing thegenetic gain of females is through embryo genotyping. This technologyallows producers to make more educated decisions on which embryosto implant. Genotyping embryos, therefore, increases genetic progressby increasing selection intensity. This technology can also identify embryonicdefects and genetic recessives to reduce early embryonic loss.Two techniques can be used to acquire biopsies from embryos for genomictesting. The first method is blade biopsy, which can be used forembryos in the late-morula or blastocyst stage sampling cells from thetrophectoderm. The second method is ideal for cleavage-stage or morula-stage embryos. This method utilizes a needle to aspirate cells fromthe embryo; it requires that enough cells be collected to complete genetesting but must ensure there are not too many taken that will compromisethe continued development of the embryo. Because sufficient DNAcannot be obtained to conduct a SNP-chip genotyping, enzymatic pre-amplificationof the biopsy is required. However, fertility of the genotypedembryos is still a concern. Single-cell gene sequencing is a technologythat will be available in the future, which would increase the integrityof the embryos and further the genetic improvement of dairy cows.