Interbull genomic evaluation of small Holstein populations: InterGenomics-Holstein (IG-HOL)


  • Simone Savoia


In December 2020 Interbull Centre launched a new Service for the international genomic evaluation of small Holstein populations: “InterGenomics-Holstein” (IG-HOL). The IG-HOL Service’s principles are to: a) have two categories of participants: IG-HOL countries (small Holstein populations’ countries), and “Contributors” (larger Holstein populations’ countries); b) pool genotypes provided by both participation categories creating a unique reference population (without sharing any genotypes among participants); c) predict gEBVs on each specific IG-HOL country-trait combination scale (for the traits evaluated in the Interbull MACE Service), by adapting to Holstein specificities the methodology used in the Interbull InterGenomics Brown Swiss Service; d) apply the Interbull method for approximating genomic reliabilities.

In the IG-HOL December 2020 routine run 12 280 male genotypes submitted by 4 IG-HOL countries (IRL, ISR, KOR, SVN) and 4 Contributors (DEU, DFS, FRA, PRT) were used in the genomic evaluation of 30 traits predicting gEBVs for 89 IG-HOL country-trait combinations. The size of the pooled reference population ranged from 4 645 bulls (body condition score - conformation trait) to 7 544 bulls (milk, fat, and protein - production traits). As expected, for reference bulls the predicted IG-HOL gEBVs showed high correlations with MACE EBVs, while lower correlations were observed for young bulls comparing their IG-HOL gEBVs to MACE PAs. The reliability gain was satisfactory, with an average increase across all 30 traits of +0.22 for young bulls’ genomic reliabilities vs the MACE PAs’ reliabilities.

These results show that IG-HOL is a valuable Service, especially for countries with small Holstein populations which cannot benefit from being part of large international genotype-exchange consortia.