10 Years of Genomic Selection: What’s Next?

{The following is an extract from an extension article by Brian Van Doormaal, Chief Services Officer, Lactanet}

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It’s been 10 years since the introduction of genomic evaluations in August 2009 and the dairy sector has seen an unprecedented annual rate of increase in the average genetic merit of young bulls entering artificial insemination (A.I.) throughout North America, which now exceeds 120 Lifetime Profit Index (LPI) points and $200 Pro$ per year.  With such a continuous year over year boost in the genetic makeup of genomic young sires offered through A.I. companies, these bulls now represent two-thirds of the total semen market share in Canada.

Figure 1 shows the impact of genomics on the increased rate of genetic progress very clearly. The steady rate of annual gain before genomics, which was 46 LPI points and $79 Pro$ per year, suddenly switched after 2009.  During the past five years, the average rate of genetic gain has increased by 2.2-fold, reaching 102 LPI points and $180 Pro$ annually. The dashed lines since 2009 in Figure 1 reflect the expected genetic progress that would have been achieved for both LPI and Pro$ in Canadian Holsteins if genomics had not been introduced.

Figure 1: Rate of Genetic Progress Achieved in Canadian Holsteins With Genomics

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Genomics provides an unprecedented opportunity to realize selection objectives for lower heritability traits even if they have negative genetic correlations with traits of moderate or higher heritability. Figure 2 shows the impact that genomics has had on genetic progress for individual traits. The first key point to notice is that positive genetic gain is now being realized for all of the major production, conformation and functional traits in addition to Pro$, LPI and its three components. Before genomics, in addition to losing ground for Daughter Fertility, Persistency, Milking Temperament and the Health & Fertility component of LPI, very little genetic progress was being made for other traits including Fat and Protein Deviations, Milking Speed, Daughter Calving Ability and Metabolic Disease Resistance. For all of the other eleven traits in Figure 2, the average rate of genetic gain realized with genomics has increased two-fold.

Figure 2: Genetic Gain Achieved in Canadian Holstein During the Past 5 Years Compared to 5 Years Before the Introduction of Genomics

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What will the future of genomic selection look like?

We are at just the tip of the iceberg when it comes to genomic selection. Given the experience over the past ten years, we can expect to see the following over the next decade:

  • The introduction of a vast array of new traits of economic and social importance, most of which have not yet even been considered by dairy farmers;
  • Increased use of sexed semen, in-vitro fertilization and other advanced reproductive technologies, which also promote the increased use of beef semen to breed dairy cows;
  • Use of DNA genotypes for improved selection strategies balancing genetic gain with maintenance of genetic diversity, including the use of genome-based mating programs;
  • A significant restructuring and consolidation of the A.I. sector, leading to a handful of larger, multi-national breeding companies;
  • Significant value-added benefits from DNA genotyping including automated parentage discovery and recording as well as traceability of dairy animals and food products.

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