Page 7 - Midway District - March 2017

KASHLY SCHWEER LIVESTOCK

Across-breed EPD Adjustments

The use of Expected Progeny Differences (EPD) for primarily upon the accuracy of the within-breed EPD of
selection decisions is limited to within breeds. In order the individual bulls being compared.
to compare animals across breeds, additive adjustment
factors must be applied to put EPD values on a common Across-breed EPD are most useful to the
Angus base. Each year, researchers at the U.S. Meat commercial producers purchasing bulls of two or more
Animal Research Center (USMARC) in Clay Center, breeds to use in crossbreeding systems. An example of
Neb. develop these adjustment factors. The updated how to use the across-breed adjustment factors to
across-breed EPD adjustments are released annually at compare Angus and Hereford bulls for birth weight and
the Beef Improvement Federation (BIF) convention. weaning weight is presented in Table 2.

Current Adjustment Factors Table 2. Example of using across-breed adjustment factors
Across-breed EPD adjustment factors are currently to convert noncomparable within-breed EPD to comparable
across-breed EPD.
calculated for 18 breeds for four or more traits
including: birth weight, weaning weight, yearling ANGUS Adj. Factors1 BIRTH WEANING
weight, maternal milk, marbling score, ribeye area and EPD2 WT WT
fat thickness. The most recent across-breed EPD AB-EPD3
adjustment factors (released at the 2016 BIF 0.0 0.0
Convention) are in Table 1.
Bull #1 0.1 63
Calculating Across-breed EPD
Animals of differing breeds can be compared on the 0.1 63

same EPD base after adding the specific adjustment HEREFORD Adj. Factors1 2.3 - 7.8
factor to the EPD produced by the representative breed Bull #2 EPD2 -2.1 55
association. The accuracy of across-breed EPD depends AB-EPD3 0.2 47.2

Table 1. Adjustment factors to estimate across-breed EPD. Kuehn and Thallman, 2016

BREED BIRTH WT WEANING WT YEARLING WT MILK MARBLING RIBEYE FAT
SCORE AREA THICKNESS
ANGUS 0.0 0.0 0.0 0.0
HEREFORD 2.3 - 7.8 - 28.6 - 17.3 0.00 0.00 0.000
RED ANGUS 2.5 - 31.4 - 34.6 3.3 - 0.31 - 0.07 - 0.056
SHORTHORN 4.7 - 36.6 - 17.3 4.1 - 0.27 0.01 - 0.016
SOUTH DEVON 3.3 - 11.4 - 27.1 3.9 - 0.14 0.37 - 0.105
BEEFMASTER 4.7 17.9 0.5 5.9 - 0.08 0.29 - 0.133
BRAHMAN 10.3 45.1 6.6 23.8
BRANGUS 3.3 12.0 4.0 6.3 - 0.78 - 0.05 - 0.145
SANTA GERTRUDIS 5.7 36.3 43.0 17.0
- 0.54 - 0.09 - 0.08
BRAUNVIEH 1.9 - 25.5 - 50.0 - 0.8 - 0.092
CHAROLAIS 8.0 34.6 40.4 8.2 - 0.7 0.78 - 0.208
CHIANGUS 3.2 - 27.0 - 40.5 - 1.7 - 0.33 1.01 - 0.093
GELBVIEH 2.8 - 22.6 - 29.3 2.3 - 0.34 0.34
LIMOUSIN 2.3 - 18.2 - 41.3 - 13.7 - 0.27 0.75 - 0.132
MAINE ANJOU 4.2 - 30.5 - 38.7 - 6.2 - 0.43 1.01 - 0.187
SALERS 1.8 - 7.3 - 25.7 5.9 - 0.57 0.97 - 0.196
SIMMENTAL 3.2 - 9.4 - 12.1 4.4 - 0.09 0.94 - 0.129
TARENTAISE 3.4 25.1 5.6 24.2 - 0.34 0.49