Interbull Routine Genetic Evaluation for Udder Health Traits

April 2012

Introduction
The latest test international evaluation for udder traits took place as scheduled at the Interbull Centre. Data from twentysix (26) countries were included in this evaluation.

International genetic evaluations for udder health traits of bulls from Australia, Austria-Germany, Belgium, Canada, Czech Republic, Denmark-Finland-Sweden, Estonia, France, Hungary, Ireland, Israel, Italy, Japan, Netherlands, New Zealand, Norway, South Africa, Slovak Republic, Spain, Switzerland, the United Kingdom, the United States of America, Poland, Lithuania, Latvia and Portugal were computed. Brown Swiss, Holstein, Red Dairy Cattle, Guernsey, Jersey and Simmental breed data were included in this evaluation.

Changes in national procedures
Changes in the national genetic evaluation of udder health traits are as follows:

CHANGES COMPARED TO THE DECEMBER ROUTINE RUN WITH S-MGS PEDIGREE:

Interbull has since the beginning been using sire-MGS relationships for International genetic evaluations of dairy bulls. It is, however, well known that International genetic evaluations are sensitive to genetic groups. It has therefore been suggested to include bull dams in the pedigree in order to move genetic groups further away from animals with data.

Along with the change of evaluation workflow the complete system has been streamlined and prepared for a future use of proofs and parameters uploaded to the database. Also, the new system is not using the submitted standardization factors but does an internal standardization based on the raw mean and standard deviations in the edited proof files.

The solver that has been in use so far has been using direct inversion. However, the dramatic increase in the size of the MME caused by including females in the evaluation rendered the use of direct inversion for the evaluation of Holsteins infeasible.

The solver has therefore been replaced by an iterative solver using PCG. For the current test run all analyses were performed by the streamlined package where changes mentioned above were implemented. 

Both correlation estimation and breeding value predictions are now moved from a 32-bit server to a 64-bit server and also the Fortran compiler has changed from Absoft to Gfortran.

Data and method of analysis
Data were national genetic evaluations of AI sampled bulls with at least 10 daughters or 10 EDC (for clinical mastitis and maternal calving traits at least 50 daughters or 50 EDC, and for direct calving traits at least 50 calvings or 50 EDC) in at least 10 herds. Table 1 presents the amount of data included in this Interbull evaluation for all breeds.

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 presents the date of evaluation as supplied by each country in the 01x-proof file.

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

Scientific literature
The international genetic evaluation procedure is based on international work described in the following scientific publications:

International genetic evaluation computation:

Schaeffer. 1994. J. Dairy Sci. 77:2671-2678
Klei, 1998. Interbull Bulletin 17:3-7

Verification and Genetic trend validation:

Klei et al., 2002. Interbull Bulletin 29:178-182.
Boichard et al., 1995. J. Dairy Sci. 78:431-437

Weighting factors:

Fikse and Banos, 2001. J. Dairy Sci. 84:1759-1767

De-regression:

Sigurdsson and G. Banos. 1995. Acta Agric. Scand. 45:207-219
Jairath et al. 1998. J. Dairy Sci. Vol. 81:550-562

Genetic parameter estimation:

Klei and Weigel, 1998, Interbull Bulletin 17:8-14
Sullivan, 1999. Interbull Bulletin 22:146-148

Post-processing of estimated genetic correlations:

Mark et al., 2003, Interbull Bulletin 30:126-135
Jorjani et al., 2003. J. Dairy Sci. 86:677-679
http://www.interbull.org/documents/genetic_correlation_estimation_procedure.pdf 

Time edits

Weigel and Banos. 1997. J. Dairy Sci. 80:3425-3430

International reliability estimation

Harris and Johnson. 1998. Interbull Bulletin 17:31-36

Next routine international evaluation
The next routine evaluation of Interbull for production, conformation, udder health, longevity, calving, female fertility and workability traits is scheduled for August 2012. Deadline for sending data to the Interbull Centre is Tuesday July 31, 2012, 17:00 CET; confidential distribution of results is targeted for Thursday August 9, 2012, with earliest possible official release of results on August 14, 2012. 

Next test international evaluation
The next test run for production, conformation, udder health, longevity, calving, female fertility and workability traits will take place in September 2012. 

Countries planning to introduce changes in their national evaluation procedures and wishing to have them included in the routine Interbull evaluation, should have their data examined in this test run. New data and validation results should be sent to the Interbull Centre no later than September 4, 2012, 17:00 CET.

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;

For all communication regarding Interbull services, please use: interbull@hgen.slu.se