Submitted to: Beef Improvement Federation Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/10/2008
Publication Date: 6/30/2008
Citation: Kuehn, L.A., Van Vleck, L.D., Thallman, R.M., Cundiff, L.V. 2008. Across-breed EPD tables for the year 2008 adjusted to breed differences for birth year of 2006. In: Proceedings of the Beef Improvement Federation 30th Research Symposium and Annual Meeting, June 30 to July 3, 2008, Calgary, Alberta, Canada. p. 53-74. Interpretive Summary: Since 1989, records from the Germplasm Evaluation project at the U.S. Meat Animal Research Center have been used to derive adjustment factors which allow comparison of the genetic merit of animals in different breeds. The factors simply are added to the expected progeny differences (EPD) calculated by each breed association in individual analyses. For example, EPD of a Charolais bull can be equitably compared to EPD of a Gelbvieh bull by adding the respective breed adjustment factor to each bull’s EPD. The adjustment factors are useful to commercial producers who may wish to compare the genetic merit of bulls from more than one breed in crossbreeding programs. This report is presented at the annual meeting of the Beef Improvement Federation. Adjustment factors are calculated on growth and milk traits for 16 different breeds (Angus, Beefmaster, Brahman, Brangus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Maine-Anjou, Red Angus, Salers, Shorthorn, Simmental, South Devon, and Tarentaise). Results from the report are the basis for a press release containing the current across-breed adjustment factors and instructions on their use. This release is distributed to producers, farm magazines, the artificial insemination industry, and breed associations. The adjustments are calculated for birth, weaning, and yearling weight, maternal milk, and carcass traits (marbling, ribeye area, fat depth).
Technical Abstract: Records of F1 and 3-way cross progeny of 16 breeds of sire and maternal grandsire, respectively, were used to estimate differences among the breeds for birth, weaning, and yearling weight and for maternal effects of weaning weight and among 8 of the 16 breeds for carcass marbling, ribeye area, and fat depth. The records were also used to estimate regression coefficients of progeny performance on breed association EPD. The regression coefficients represent the proportion of the differences in sire EPD that were exhibited in the progeny at USMARC and are used to adjust the breed differences estimated from USMARC data to the differences between animals in the breed born in 2006 (based on the 2006 breed average EPD). Using these adjusted breed differences, adjustment factors were calculated that can be added to breed association EPD to allow comparison of bulls from the 16 breeds (Angus, Beefmaster, Brahman, Brangus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Maine-Anjou, Red Angus, Salers, Shorthorn, Simmental, South Devon, and Tarentaise). This report details the calculations used for the annual update of the procedure first implemented in 1991. Changes for 2008 included the addition of progeny weights on 4 breeds and grandprogeny weights on 9 breeds and the addition of adjustment factors for carcass traits.