Weekly genomic-enhanced carcass EPDs are calculated from an integrated analysis of the Beef Improvement
Records carcass, ultrasound, growth (weaning weight), 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. Growth (weaning weight), 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: | Avg | SD1 | Avg | SD |
| Avg. age at harvest, days | 436 | 30 | 555 | 60 |
| Adj.2 carcass wt., lb. | 710 | 86 | 716 | 102 |
| Adj. fat thickness, in. | .60 | .19 | .55 | .19 |
| Adj. ribeye area, sq. in. | 12.08 | 1.37 | 12.16 | 1.55 |
| Adj. marbling score | 6.75 | 1.30 | 6.37 | 1.39 |
| No. of heifers | 5,772 | 6,967 |
| |
| Steers: | | | | |
| Avg. age at harvest, days | 437 | 26 | 524 | 44 |
| Adj. carcass wt., lb. | 799 | 85 | 781 | 101 |
| Adj. fat thickness, in. | .57 | .17 | .54 | .19 |
| Adj. ribeye area, sq. in. | 12.63 | 1.35 | 12.66 | 1.45 |
| Adj. marbling score | 6.24 | 1.09 | 5.89 | 1.27 |
| No. of steers | 77,182 | 28,322 |
1SD = standard deviation.
2Carcasses were adjusted to 480 days of age at harvest.
Table 2: Yearling Angus live-animal and ultrasound measures
| Bulls | Heifers | Steers |
| Trait | Avg | SD1 | Avg | SD1 | Avg | SD1 |
| Age, days | 370 | 26 | 389 | 30 | 404 | 38 |
| Gain, lbs/day | 2.92 | 0.69 | 1.51 | 0.52 | 2.84 | 0.74 |
| Adj. scan weight, lb. | 1119 | 140 | 866 | 113 | 1103 | 168 |
| Adj. %IMF, % | 3.83 | 1.08 | 4.80 | 1.37 | 4.94 | 1.43 |
| Adj. ribeye area, sq. in. | 12.60 | 1.89 | 9.77 | 1.73 | 12.30 | 2.26 |
| Adj. 12-13th rib fat thickness, in. | .28 | .10 | .26 | .11 | .40 | .15 |
| Adj. rump fat thickness, in. | .30 | .11 | .30 | .12 | .41 | .15 |
| No. of Animals | 1,138,102 | 767,815 | 13,206 |
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 |