INTERBULL Routine Genetic Evaluation for Holstein Conformation Traits

February 2001

Introduction

International genetic evaluations for 18 conformation traits of Holstein bulls from Australia, Belgium, Canada, Denmark, France, Finland, Germany, Italy, the Netherlands, Spain, Switzerland, Sweden, the United Kingdom, and the United States of America were computed in this evaluation.

New data (national genetic evaluations) included in this evaluation

• Due to changes over time in the trait definitions, The Netherlands decided to exclude older records for the following five traits: chest width, body depth, angularity, rump width, and foot angle. Also the formula for calculating overall conformation was updated. These changes were tested in the March 2000 test-run but not implemented until this routine evaluation. As a result correlations used in the routine evaluation for these traits are a blend of the March 2000 correlations for NLD and the September 2000 correlations for all other countries. Additional bending was necessary to make the resulting correlation matrix positive definite, and small changes in correlations not involving NLD might be observed because of this.

Changes in the INTERBULL evaluation:

• Minimum birth year of bulls included in the international evaluation for dairy production and conformation traits was updated by 1 year, a procedure that was introduced at the February routine evaluation in 1998. The objective is to maintain a constant window of recent data across country on which international evaluations are based, in light of theoretical evidence that such recent data best describe the current situation in changing populations and more accurately assess the genetic merit of young bulls. Therefore, in this evaluation run minimum birth year was set to 1984 in the Holstein evaluation and 1979 in the evaluation of other breeds. All identifiable pedigree information was included in each evaluation.

Data and method of analysis

Data were national genetic evaluations of AI sampled bulls with daughters in at least 10 herds. Table 1 presents the amount of data included in this Interbull evaluation, and Table 2 trait definitions as provided by participating countries.
Estimated genetic parameters are shown in APPENDIX I. Parameters are listed by trait and country.
National proofs were first de-regressed within country and then analysed jointly with a linear model including the effects of evaluation country, genetic group of bull and bull merit. Heritability estimates used in both the de-regression and international evaluation were as in each country's national evaluation (Table 2).
Ancestor-bulls without own proofs were traced back two generations from the oldest bulls with proofs in order to increase across country connections and account for the effect of selection.
Genetic groups were defined according to unidentified parents by national origin, breed and birth year of the bull and path of selection (sire, maternal grand-sire, maternal grand-dam). Birth year grouping was by 1-5 year periods. Smaller groups (consisting of less than 15 bulls) were combined.

Publication of INTERBULL evaluations

Results were distributed by the Interbull Centre to designated representatives in each country. The international evaluation file comprised international proofs expressed on the base of each country included in the analysis. Such records readily provide more information on bull performance in various countries, thereby minimising the need to resort to conversions.

At the same time, all recipients of Interbull results are expected to honour the agreed code of practice, decided by the Interbull Steering Committee, and only publish international evaluations on their own country scale. Evaluations expressed on another country scale are confidential and may only be used internally for research and review purposes.

Next routine international evaluation

The next routine international evaluation for dairy production and conformation traits is scheduled for May 2001. New data for that run should reach the Interbull Centre not later than May 4, 2001, 17:00 Central European Time (CET); in any case, the most recently received data will be considered. Results will be distributed on May 14, 2001.

Next test international evaluation

The next test international evaluation for dairy prodiction and conformation traits is scheduled for March 2001. Countries wishing to enter the system for the first time or planning to submit new information (modified national evaluation procedure, new breeds etc) for the following routine evaluation must have their data tested in this test-run.

ALL countries are, however, expected to send data with the new weighting factors for the conformation test-run using the modified 015-file format.
Deadline for sending new data to the Interbull Centre for the next test-run is March 1, 2001.

Means of result distribution from the Interbull Centre

Electronic exchange of data is probably more efficient than anything else. Currently most countries in the service have established internet connections and receive international evaluation results on the day of their release. Subscribers to the service that do not already exercise this option are encouraged to consider it and establish an internet connection and ftp account. When such accounts are available, please provide their specifications to the Interbull Centre. Until then, data will be delivered on CD-ROM's.

For more information about the international genetic evaluation service please contact the INTERBULL Centre: address: SLU Box 7023, 750 07 Uppsala, Sweden;  fax: +46-18-672648;

e-mail: Ulf.Emanuelson_at_hgen.slu.se

e-mail: Thomas.Mark_at_hgen.slu.se

e-mail: Freddy.Fikse_at_hgen.slu.se

e-mail: Hossein.Jorjani_at_hgen.slu.se

e-mail: Jan.Philipsson_at_hgen.slu.se

e-mail: Dan.Englund_at_hgen.slu.se