Reading a Carcass Data Report: What Does it Mean?

By Brian Rainey, Graduate Student, MSU Animal and Range Sciences Department

Interpreting the components of a carcass data report provides the rancher with an understanding of how well their calves met customer requirements, genetic potential, feedlot performance and value of the product compared to national standards.

Normally a carcass report includes the slaughter date, when the animal was graded, number of steers or heifers, yield (dressing percent), quality grade (% Prime, % Choice, and % Select or lower) and yield grade (1, 2, 3, 4, 5). The report should also include a marbling score. Finally the legend will de ne abbreviations for "out" cattle (condemned) and should include program codes when individual whole carcass data is collected. This article provides a brief description of how these values were determined.

Dressing percent (DP) is calculated using the following equation:

DP = 100 - (live weight hot carcass weight) / live weight x 100.

For example if steer "a" had a live weight of 1250 lbs. and his hot carcass weight was 792 lbs. then his dressing percent would calculated as:

DP = 100 - (1250- 792) / 1250 x 100 making steer a's dressing percent 63.36.

Table 1 illustrates individual carcass data for two steers as it may appear on a data report.

As cattle move through the packing plant they are assigned a carcass identi cation number that will allow for correlation with electronic ID tags and or visual ID tags. This article also includes a list of definitions followed by quality and yield grade determinations for these two animals.

Hot carcass weight is the weight of the carcass following exsanguination and after removal of the hide and offal (often called "the drop").

Marbling score is the score assigned to a carcass based on the amount of intramuscular fat of the longissimus muscle and is determined by a USDA grader.

PYG or preliminary yield grade is based upon fat thickness and is just an estimate.

BF or back fat in inches is the measurable of fat over the longissimus muscle between the 12th and 13th rib interface.

% KPH is the % of internal fat found in the cavity of a carcass speci cally in the regions of the kidneys, pelvis, and heart. It may be estimated or calculated based on the change in carcass weight following removal of fat from these areas.

REA or ribeye area is the area of the longissimus muscle in square inches and is measured between 12th and 13th rib.

Quality grade is determined based upon the marbling and maturity of a carcass and de nes the overall quality of individual carcasses. Marbling is an indicator of juiciness and avor in retail cuts of meat Marbling scores as they are presented on a carcass report generally are as follow: 100-199 = practically devoid, 200-299 = traces, 300-399 = select, 400-499 = small, 500-599 = modest, 600-699 = moderate, 700-799 slightly abundant, and 800-899 = moderately abundant.

Often times these numbers may be expressed as a decimal as seen in Table 1. As a result, an that has a marbling score of 4.8 is equivalent to marbling score of 480 or "small" amounts of marbling Feeder calves in the U.S. tend to be harvested at average age of approximately 18 months. Cattle with a physiological maturity of less than 30 months of are considered "A" maturity and, therefore, qualify the grades of Prime, Choice, Select, and Standard. we consider a carcass to have a marbling score of and to be of "A" maturity, then that animals' carcass would have a quality grade of low choice (Ch -). A 390 would be considered to be a Select. For a complete quality grade chart, refer to the Montana Beef Quality Assurance handbook, p. 19, or go on-line to www.mbn.montana.edu, www.usda.gov, or www.beef.org.

USDA Yield Grade (YG) is the subjective yield grade that is assigned to carcasses in a packing plant by a USDA grader. Calculated YG is the yield grade based on a calculation utilizing the fat thickness, REA, KPH, and HCW of an individual carcass.

Yield grades determine which carcasses have the greatest amounts of saleable meat ("cutability"). Yield grades are numbered 1 through 5 with 1 having the most cutability and 5 having the least. Yield grades are calculated based upon the Hot Carcass Weight (HCW), Ribeye area (REA), Backfat Thickness, and % Kidney, Pelvic and Heart fat (KPH) for an individual carcass. The formula for calculating YG is:

2.5 + (2.5 x fat-thickness, in) + (0.2 x KPH) (0.32 x REA, in2) + (0.0038 x HCW lbs.).

The calculated YG for animal 1 from the previous table would be determined by the following:

YG = 2.5 + (2.5 x 0.88) + (0.2 x 2.2) (0.32 x 11.2) + (0.0038 x 707)

YG = 2.5 + 2.2 + 0.44 3.584 + 2.6866

YG = 4.24

The calculated YG for animal 2 would then be:

YG = 2.5 + (2.5 x 0.40) + (0.2 x 2.0) (0.32 x 14 (0.0038 x 767)

YG = 2.5 + 1.0 + 0.40 4.48 + 2.9146

YG = 2.33

The National Cattlemen's Beef Quality Audit suggested that the following carcass characteristics were considered optimal for consumer eating satisfaction.

Suggested Industry Targets

• Carcass weight (HCW) 600-800 lbs.
• Backfat thickness (BF) 0.3-0.45 inches
• Ribeye area (REA) 12.5-14.0 sq. in.
• Yield grade (YG) 2.0 or less
• Quality grade (QG) Select + to Choice

Based on these targets, how did steer 1 do in of carcass weight, ribeye area, yield grade and quality grade? For more information on cattle grading and carcass data reports please refer to the websites above or contact Dr. John Paterson, PAS, Extension Beef Specialist at 406-994-5562 or johnp@montana.

Beef: Questions & Answers is a joint project between MSU Extension and the Montana Beef Council. This column informs producers about current consumer education, promotion and research projects funded through the $1 per head checkoff. For more information, contact the Montana Beef Council at (406) 442-5111 or at beefcncl@mt.net

 

Return to regular view	Text-only	Updated: 08/29/2006