Comparison of domestic and foreign genotypes by country and continent

Authors: Tooker, Melvin; Cooper, Tabatha; DURR, JOAO - Council On Dairy Cattle Breeding; Vanraden, Paul

Submitted to: Interbull Annual Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/8/2015
Publication Date: 8/19/2015
Citation: Tooker, M.E., Cooper, T.A., Durr, J., Van Raden, P.M. 2015. Comparison of domestic and foreign genotypes by country and continent. Interbull Annual Meeting Proceedings. Interbull Bulletin 49:14–18.

Interpretive Summary: Genomic and pedigree relationships, inbreeding, pedigree completeness and accuracy, and genomic merit were examined for 44 countries using the national dairy cattle database as of April 2015. Countries were group into geographical continents and showed similar genomic and pedigree relationships of foreign animals to the domestic reference population. Inbreeding levels were also similar across continents. Pedigree completeness was highest for western Europe with 98% and lowest for Latin America with 68%. Breeders in many countries are genotyping animals with high relationship to the North American reference population. Use of foreign genotypes contributes to U.S. genomic evaluations by improving pedigree discovery and identifying harmful recessive haplotypes. Direct evaluation of foreign genotypes allows males and females from many countries to be evaluated together on the same scale, enabling simpler genomic selection. Inclusion of foreign animals in the reference population should make predictions more accurate across environments.

Technical Abstract: Genomic evaluations for foreign animals are easily computed, and reliabilities are highest for animals well connected to the domestic reference population and managed in similar environments. Genomic and pedigree relationships, inbreeding, pedigree completeness, pedigree accuracy and genomic merit were examined for 880 797 genotyped animals from 44 countries in the U.S. national database as of April 2015. For genotyped Holsteins from continents other than North America, >60% of sires were North American, and relationships to the reference population were nearly as high for the 203 637 foreign animals as for the 677 160 domestic animals. Pedigrees from all continents were fairly complete. About 94% of sires were reported by breeders, and half of the 6% of sires that were missing were discovered from genotypes. From 2 to 16% of animals had incorrect sires, and >80% of those errors were corrected. Genomic net merit across all continents was higher than conventional parent averages and the domestic genetic base of cows born in 2010. Countries with smaller dairy populations or without advanced data collection and breeding systems can obtain predictions from larger databases and for additional traits by exchanging genotypes across country borders, allowing animals from many countries to be evaluated together on the same scale.