National Index Correlations and Actual vs. Expected Use of Foreign Sires
Abstract
Differing selection indexes, genetic correlations < 1.0, and missing traits each cause reranking of the same bulls in different countries. To quantify, correlations were estimated using selection indexes from 15 major countries as of 2020. When different national indexes were used to compute rankings on the same EBV scale, most correlations were ≥ 0.80 and many were ≥ 0.90. Correlations were even higher when 1 index was applied to EBVs on all 15 scales. Thus, index definitions generally caused more reranking than EBV differences across scales. Foreign bulls were >80% of the top bulls in nearly all countries but often sired <50% of domestic cows. Reasons might include health restrictions, higher prices, lack of information, lack of technician service, or protectionism. Foreign bull use in each country is now documented in a web query. Because index correlations are high, many countries can improve genetic progress by using domestic bulls less and foreign bulls much more.
Downloads
Published
Issue
Section
License
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).