INTERBULL Routine Genetic Evaluation for Dairy Production Traits

February 1999

Introduction

The eleventh routine international evaluation for dairy production traits took place as scheduled at the Interbull Centre. Data from twenty two (22) countries were included in this evaluation. Results were distributed on February 8, 1999, to designated representatives in twenty three (23) countries currently subscribing to the service. International genetic evaluations for milk, fat and protein yields of bulls from Canada, Germany, Denmark, Finland, France, Italy, the Netherlands, Norway, Sweden, the United States of America, Switzerland, the United Kingdom, New Zealand, Australia, Austria, Belgium, Ireland, Spain, the Czech Republic, Slovenia, Estonia and Israel were computed. Ayrshire, Brown Swiss, Guernsey, Holstein, Jersey and Simmental breed data from 8, 10, 4, 22, 7 and 8 bull populations, respectively, were included in this evaluation.

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

• Data from a new model considered in Canada (all breeds) were included. This is a multiple trait random regression test-day model with new genetic parameters.
• Systems to identify non-AI and import (second proof) bulls in some countries are still in development stage; this may account for differences in national data set sizes from one evaluation to the next, in addition to young bulls first entering the system. In all such countries, progress is being made towards consistent definition systems. Non-AI bulls are not included in Interbull evaluations whereas import bull proofs are subject to stricter editing criteria ie, presence of first country proof in the Interbull data and second country proof based on minimum 75 daughters in 50 herds (40/20 for breeds other than Holstein).

Changes in the INTERBULL evaluation:

• Minimum birth year of bulls included in the international evaluation (breeding value estimation) was updated by 1 year, a procedure that was introduced at the previous February routine evaluation. 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 1982 in the Holstein evaluation and 1977 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 type and amount of data included in this Interbull evaluation. The difference between "No. Records" and "No. Bulls" is explained by common bulls with proofs in more than one country. The entry "Publishable Proofs" reflects bulls whose international evaluations were distributed to service customers. The difference between "No. Bulls" and "Publishable Proofs" is explained by bulls not meeting the minimum criterion for official publication in the country of origin.

Estimated genetic parameters are shown in APPENDIX I. Parameters are listed by breed, 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. Different breeds were analysed separately. Heritability estimates used in both the de-regression and international evaluation were as in each country's national evaluation (Table 1).

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. Small groups (generally consisting of less than 10 bull) were combined.

Scientific literature

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

1. International genetic evaluation computation

L. Schaeffer. 1994. J. Dairy Sci. 77:2671-2678

2. Genetic trend validation

D. Boichard et al. 1995 J. Dairy Sci. 78:431-437

3. De-regression and genetic parameter estimation

A. Sigurdsson and G. Banos. 1995. Acta Agric. Scand. 45:207-219

A. Sigurdsson et al. 1996. Acta Agric. Scand. 46:129-136

P. Rozzi and L. Schaeffer. 1996. Interbull Technical Workshop, Verden, Germany, 25-26 Nov

4. Data edits

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

5. International reliability estimation

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

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 may only be used for internal purposes.

Use of INTERBULL evaluations in various countries

Table 2 presents current national policies regarding use of Interbull evaluations in countries participating with data. These statements do not provide permission to any country for publication of international evaluations expressed on the scale of another country. Publication references pertain to each country's own scale.

Table 3 shows release dates of national and Interbull evaluation results in various countries.

INTERBULL conversions

Since all data are now becoming available, conversions are not as useful as before. When an international proof is available, customers of the service are encouraged to use this instead of a converted proof. Conversion coefficients were, however, computed from international evaluation results and may be considered "Estimated Interbull Conversions" for the interim until the next international evaluation run.

Next routine international evaluation

The next routine international evaluation is scheduled for May 1999. New data for that run should reach the Interbull Centre not later than April 30, 1999; in any case, the most recently received data will be considered. Results will be distributed on May 10, 1999.

Next test international evaluation

The next test international evaluation is scheduled for March 1999. 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. Deadline for sending new data to the Interbull Centre for the next test-run is March 1, 1999.

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 in diskettes.

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: Georgios.Banos_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