Interbull Routine Genetic Evaluation for Conformation Traits

May 2007

Introduction

International genetic evaluations for conformation traits of Brown Swiss, Guernsey, Holstein, Jersey and Red Dairy Cattle bulls from Australia, Belgium, Canada, Czech Republic, Denmark, Estonia, France, Finland, Germany, Hungary, Italy, Japan, the Netherlands, Norway, New Zealand, Poland, Rep. of South Africa, Spain, Sweden, Switzerland, the United Kingdom, and the United States of America were computed in this evaluation.

New data (national genetic evaluations) included in this evaluation:

• Canada switched to a weighted-records analysis and allowed classifications in later lactations (at a reduced weight) for cows that do not have a classification in first parity.
• USA (Holstein) changed the evaluation for overall conformation by including more pedigree information and running for more rounds of iteration.
• The Netherlands (Brown Swiss) changed the definition of overall conformation.
• New Zealand introduced a multiple-trait evaluation. Body traits are simultanously evaluated as well as udder traits. Overall udder score is evaluated with a single-trait model.

Changes in the Interbull procedures

• The procedure to obtain conversion coefficients has been modified. Previously such equations were only provided for cases (countries) with more than 20 bulls that met certain criteria (birth year, reliability, etc.). In this test-run conversion equations are obtained for the other cases (countries) as well based on the theoretical b-value and an estimated a-value. The theoretical b-value is computed as rG(i,j)*std(i)/std(j), where rG(i,j) is the genetic correlation between country i and j, and std(j) is the sire standard deviation for country j. The a-value is estimated as m(i)-b*m(j) where m(i) is the mean international proof for country i based on all bulls progeny tested only in one country born since 1996 (Holstein; 1995 for other breeds). 
   

Data and method of analysis

Data were national genetic evaluations of AI sampled bulls with daughters in at least 10 herds. Table 1, table 2, table 3, table 4 and table 5 presents the amount of data included in this Interbull evaluation for Brown Swiss, Guernsey, Holstein, Jersey and Red Dairy Cattle, respectively. Table 6 gives trait definitions as provided by participating countries.

Estimated genetic parameters are shown in APPENDIX I, APPENDIX II, APPENDIX III, APPENDIX IV and APPENDIX V for Brown Swiss, Guernsey, Holstein, Jersey and Red Dairy Cattle, respectively. 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 6).

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.

Analysis followed a similar procedure as Mace for production traits.

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 and unit 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.

All recipients are also expected to follow the agreed guidelines for advertising genetic merit. The guidelines has been distributed to all members and is available on the Interbull homepage (http://www.interbull.org) under "Publications and Documentation/General information".

Next routine international evaluation

The next routine international evaluation for dairy production, udder health conformation, longevity, calving traits (Brown Swiss, Holstein and Red Dairy Cattle) and female fertility (Holstein) is scheduled for August 2007. New data for the August routine run should reach the Interbull Centre not later than Tuesday July 31, 2007, 17:00 Central European Time (CET); in any case, the most recently received data will be considered. The target time for distribution of results for internal review to designated representatives, who have signed a confidentiality agreement with the Centre, is Thursday August 9, 2007. Official release date of the results is targeted to be Monday August 13, 2007.

Next test international evaluation

The next test international evaluation for dairy production, conformation, udder health, longevity, calving traits (Red dairy cattle breeds [previously Ayrshire], Brown Swiss, Holstein) and female fertility traits is scheduled for September 2007. Countries wishing to enter the system for the first time or planning to submit new information (modified national evaluation procedure, new breeds etc) for following routine evaluations must have their data tested in this test-run.

Deadline for sending data and validation results to the Interbull Centre for the next test-run is September 4, 2007 at 17:00 CET.

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;

Please use Interbull_at_hgen.slu.se for all communication regarding Interbull services.