Interbull Routine Genetic Evaluation for Udder Health Traits

November 2005

Introduction
International genetic evaluations for milk somatic cell and clinical mastitis of bulls from Canada, Denmark, Estonia, Finland, France, Germany, the Netherlands, Norway, Sweden, Switzerland, The United Kingdom, The United States of America, Israel, Italy, Australia, Hungary, Belgium, Japan, Spain, Rep. South Africa New Zealand and Ireland were computed in this evaluation.
Ayrshire, Brown Swiss, Guernsey, Holstein, Jersey and Simmental breed data were included.

Changes in national data

• Ireland participated for the first time in the Holstein evaluation.
• Norway participated for the first time with SC data.
• The Netherlands and Germany included data on MRY bulls in the Holstein evaluation.
• Germany (Brown Swiss & Simmental) corrected an error in the computation of EDCs
• Estonia changed criteria for data inclusion, modified definition of fixed effectsand updated genetic parameters.
• Rep. South Africa introduced a (pre-) adjustment for heterogeneous variances, and updated genetic paramters.
• For Simmental udder health correlations with the wrong sign were used in two countries in the previous routine evaluation. This was corrected in the September test run.
   

Changes in Interbull procedure:

• None

Data and method of analysis

Data were national genetic evaluations of AI sampled bulls with daughters in at least 10 herds. For clinical mastitis information to be included, an additional requirement was that bulls had to have at least 50 daughters. Table 1 presents the amount of data included in this Interbull evaluation. Table 2 and table3 gives heritabilities and some additional information on national evaluations as provided by the participating countries.

Estimated genetic parameters are shown in APPENDIX I  and the number of common bulls are listed in APPENDIX II.

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 and table 3).

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 30 bulls) were combined.

International genetic evaluations were computed using effective daughter contributions (EDC) as weighting factors.

For each breed, two separate international genetic evaluations were computed. The first included milk somatic cell de-regressed proofs from individual countries. The second included de-regressed proofs for clinical mastitis as a direct trait from countries that made this information available and milk somatic cell de-regressed proofs from all other countries. Note that the second evaluation was not carried out for BSW and GUE since none of the participating countries provided clinical mastitis information.

Genetic correlation estimation procedure

See www.interbull.org/documents/genetic_correlation_estimation_procedure_042t.pdf

Next routine international evaluation

The next routine international evaluation for dairy production, udder health conformation, longevity and calving traits (Holstein) is scheduled for February 2006. New data for the February routine run should reach the Interbull Centre not later than Tuesday January 31,2005, 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 February 9, 2006. Official release date of the results is targeted to be Monday February 13, 2006.

Next test international evaluation

The next test international evaluation for dairy production, conformation, udder health, longevity and calving traits (Holsteins) is scheduled for March 2006. 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 March 1, 2006 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 has 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.