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Weekly genomic-enhanced carcass EPDs are calculated from an integrated analysis of the Beef Improvement Records carcass, ultrasound, and genomic profile databases. The weekly genetic evaluations result in a single EPD for carcass weight, marbling score, ribeye area, and fat thickness. The units of measure for EPDs are in carcass trait format – marbling score, carcass weight in pounds, carcass ribeye in square inches, and carcass fat thickness in inches. Ultrasound, carcass, genomic, and pedigree databases are simultaneously combined into one set of genomic-enhanced carcass EPDs for Angus breeding programs. Every Friday morning, the genomic-enhanced NCE EPDs are available at www.angus.org. To learn more about genomic-enhanced EPDs, click here.

The carcass and ultrasound data contributing to the evaluation are described in Table 1 and Table 2  with average adjusted measurements.

Ultrasound images incorporated into the carcass EPDs were collected by field technicians certified by the Ultrasound Guidelines Council (UGC). The images were interpreted through one of the American Angus Association's authorized ultrasound processing labs by UGC-certified lab technicians.


Table 1. Angus phenotypic averages of steer and heifer carcasses
        330 < Age < 480        481 < Age < 799
Heifers:AvgSD1AvgSD
Avg. age at harvest, days4372954447
Adj.2 carcass wt., lb.7038470596
Adj. fat thickness, in..59.18.53.19
Adj. ribeye area, sq. in.12.021.3512.061.49
Adj. marbling score6.701.306.271.34
No. of heifers        5,191        5,866
        
Steers:
Avg. age at harvest, days4372652240
Adj. carcass wt., lb.7958477599
Adj. fat thickness, in..57.17.54.18
Adj. ribeye area, sq. in.12.591.3312.581.43
Adj. marbling score6.201.085.831.23
No. of steers        72,505        25,670
1SD = standard deviation.
2Carcasses were adjusted to 480 days of age at harvest.
Table 2: Yearling Angus live-animal and ultrasound measures
BullsHeifersSteers
TraitAvgSD1AvgSD1AvgSD1
Age, days370263893040538
Gain, lbs/day2.920.691.510.522.850.74
Adj. scan weight, lb.11171388651121101169
Adj. %IMF, %3.811.064.761.364.911.43
Adj. ribeye area, sq. in.12.551.889.731.7312.242.24
Adj. 12-13th rib fat thickness, in..28.10.26.11.40.15
Adj. rump fat thickness, in..30.11.30.12.40.15
No. of Animals1,024,766706,86412,798
1SD = standard deviation.

As a review, the scoring system for marbling and its relationship to the USDA Quality Grading System is defined in Table 3. For a carcass to meet Certified Angus Beef (CAB) standards, it must have a Modest ( average Choice) or higher marbling degree, be of "A" maturity (the most youthful classification for beef), 10 to 16 square inch ribeye, less than one inch fat thickness, less than 1,000 pound hot carcass weight and have a fine to medium marbling texture. For more details, go to http://www.cabpartners.com.
Table 3. USDA quality grading system and marbling score.
Quality Grade Amount of Marbling Numerical Score
Prime + Abundant 10.0 - 10.9
Prime Moderately abundant 9.0 - 9.9
Prime - Slightly abundant 8.0 - 8.9
Choice + Moderate 7.0 - 7.9
Choice Modest 6.0 - 6.9
Choice - Small 5.0 - 5.9
Select Slight 4.0 - 4.9
Standard Traces 3.0 - 3.9
Standard Practically devoid 2.0 - 2.9
Utility Devoid 1.0 - 1.9