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ARS Home » Research » Publications at this Location » Publication #73229


item Van Vleck, Lloyd
item Cundiff, Larry

Submitted to: Beef Improvement Federation Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/15/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Beginning in 1989, records from the Germ Plasm Utilization Project at the USDA Meat Animal Research Center have provided the basis for factors which allow comparison of pairs of bulls of 12 different breeds. The factors are added to the expected progeny differences calculated by the breed associ- ations. For example, a Salers bull can be compared with a Pinzgauer bull (or any pair of bulls of the 12 breeds) for calf birth weight, weaning weight, yearling weight, and mothering ability. Thus, herd owners are not limited to comparisons among bulls of a single breed. This report updates the adjustment factors to a base year for 12 breeds as has been done annu- ally since 1991. The base year for this up-date is 1994.

Technical Abstract: Records of F1 and 3-way cross progeny of 12 breeds of sire and maternal grand sire are used to estimate differences among the breeds for birth, weaning and yearling weight, and maternal ability. The same records are used to estimate coefficients of regression for progeny performance at MARC on breed association EPDs are estimated. These regression coefficients are eused to adjust the estimates of breed differences for the difference bet- ween breed average EPD for animals born in 1994 and the average EPD of bulls used at MARC that contribute to estimates of breed differences. The regression coefficients show the proportion of differences in EPD that is exhibited in their calves at MARC. From these adjusted breed differences, factors are calculated that can be added to breed association EPD to allow comparison of bulls of different breeds. This report details the calculat- ions used for this annual update of the procedure first formalized in 1991. .Changes for 1996 included 1) combining of Polled and horned Herefords, 2) adding more records of grand progeny of Hereford, Angus, and Brahman bulls, 3) including random maternal effects in model for calculating regression of progeny on sire EPD, and 4) integrating computer programs used for analysis to eliminate human errors.