Heres some information about yield grades. PM me with your e-mail address if you want more info and I'll send you more than you probably need.
Dick
USDA yield grades identify the "quantity" or "cutability" differences among carcasses. Yield grades are 1, 2, 3, 4 and 5, and are a numerical representation of the expected percentage of closely trimmed, boneless retail cuts from the round, loin, rib and chuck. This percentage of retail cuts is the carcass cutability (Table II).
Table II. Relationship of Yield Grades and Cutability
Yield Grade % Boneless, Closely Trimmed Retail Cuts
From the Round, Loin, Rib and Chuck
1 52.6 - 54.6
2 50.3 - 52.3
3 48.0 - 50.0
4 45.7 - 47.7
5 43.3 - 45.4
The terms "yield" and "yield grade" should not be confused. "Yield" alone means dressing percentage (carcass weight divided by live weight multiplied by 100), and is not directly related to yield grades or cutability
Carcass factors used to calculate yield grade are:
Adjusted fat thickness. External fat is measured at the 12th rib perpendicular to the outside fat at a point 3/4 the length of the rib eye (longissimus) muscle (Figure 4). This measurement may be adjusted by the grader to reflect unusual fat distribution in the carcass. Special attention is given to fat deposition in the cod or udder, rump, inside round, flank, lower rib, plate and brisket areas. External fat is the most important yield grade factor. As external fat increases, the percentage of retail cuts decreases.
Percentage of Kidney, Pelvic and Heart Fat (KPH). This is a subjective estimate of the amount of fat surrounding the kidney knob, and fat in the pelvic and thoracic (heart) areas as a percentage of the carcass weight. As the percentage of KPH fat increases, the percentage of retail cuts decreases. Percentage KPH fat normally ranges from 1.0 to 4.0 percent.
Rib Eye Area. The longissimus muscle is measured at the 12th rib by using a grid expressed in square inches (Figure 5), or a compensating polar planimeter, which measures a rib eye tracing. Rib eye area is an indicator of carcass muscling; as rib eye area increases, retail cut yield increases.
Hot Carcass Weight. Generally, as carcass weight increases, the percentage of retail cuts decreases slightly due to increased fat deposition. If only chilled carcass weight is available, it can be adjusted to hot carcass weight by multiplying by 1.02 to correct for the evaporative weight loss of the carcass in the cooler.
Yield grades are calculated by using the following formula:
YG = 2.50 + (2.50 × Adjusted Fat Thickness, inches)
+ (0.20 × Kidney, Pelvic and Heart Fat %)
+ (0.0038 × Hot Carcass Weight, lb)
- (0.32 × Rib eye area, sq. in.)
For example, a carcass has 0.40 inch of fat, 2.5 percent KPH, 12.8 sq. inches of rib eye and a hot carcass weight of 750 lbs. Substitute these variables into the yield grade equation to calculate a final yield grade of 2.75:
YG = 2.50 + (2.50 × 0.4 in.)
+ (0.20 × 2.5 percent)
+ (0.0038 × 750 lbs.)
- (0.32 × 12.8 sq. in.)
YG = 2.75
In the official USDA grading program the decimals are dropped and the yield grade is reported as 2.
In review, USDA yield grades estimate the quantity of edible meat from the major wholesale cuts--round, loin, rib and chuck.
Additional information regarding USDA quality and yield grades may be obtained by requesting Official United States Standards for Grades of Carcass Beef from the United States Department of Agriculture, Agricultural Marketing Service, Livestock and Seed Division, Standardization Branch, Room 2603 South Bldg., P.O. Box 96456, Washington, D.C. 20090-6456.
Dick
USDA yield grades identify the "quantity" or "cutability" differences among carcasses. Yield grades are 1, 2, 3, 4 and 5, and are a numerical representation of the expected percentage of closely trimmed, boneless retail cuts from the round, loin, rib and chuck. This percentage of retail cuts is the carcass cutability (Table II).
Table II. Relationship of Yield Grades and Cutability
Yield Grade % Boneless, Closely Trimmed Retail Cuts
From the Round, Loin, Rib and Chuck
1 52.6 - 54.6
2 50.3 - 52.3
3 48.0 - 50.0
4 45.7 - 47.7
5 43.3 - 45.4
The terms "yield" and "yield grade" should not be confused. "Yield" alone means dressing percentage (carcass weight divided by live weight multiplied by 100), and is not directly related to yield grades or cutability
Carcass factors used to calculate yield grade are:
Adjusted fat thickness. External fat is measured at the 12th rib perpendicular to the outside fat at a point 3/4 the length of the rib eye (longissimus) muscle (Figure 4). This measurement may be adjusted by the grader to reflect unusual fat distribution in the carcass. Special attention is given to fat deposition in the cod or udder, rump, inside round, flank, lower rib, plate and brisket areas. External fat is the most important yield grade factor. As external fat increases, the percentage of retail cuts decreases.
Percentage of Kidney, Pelvic and Heart Fat (KPH). This is a subjective estimate of the amount of fat surrounding the kidney knob, and fat in the pelvic and thoracic (heart) areas as a percentage of the carcass weight. As the percentage of KPH fat increases, the percentage of retail cuts decreases. Percentage KPH fat normally ranges from 1.0 to 4.0 percent.
Rib Eye Area. The longissimus muscle is measured at the 12th rib by using a grid expressed in square inches (Figure 5), or a compensating polar planimeter, which measures a rib eye tracing. Rib eye area is an indicator of carcass muscling; as rib eye area increases, retail cut yield increases.
Hot Carcass Weight. Generally, as carcass weight increases, the percentage of retail cuts decreases slightly due to increased fat deposition. If only chilled carcass weight is available, it can be adjusted to hot carcass weight by multiplying by 1.02 to correct for the evaporative weight loss of the carcass in the cooler.
Yield grades are calculated by using the following formula:
YG = 2.50 + (2.50 × Adjusted Fat Thickness, inches)
+ (0.20 × Kidney, Pelvic and Heart Fat %)
+ (0.0038 × Hot Carcass Weight, lb)
- (0.32 × Rib eye area, sq. in.)
For example, a carcass has 0.40 inch of fat, 2.5 percent KPH, 12.8 sq. inches of rib eye and a hot carcass weight of 750 lbs. Substitute these variables into the yield grade equation to calculate a final yield grade of 2.75:
YG = 2.50 + (2.50 × 0.4 in.)
+ (0.20 × 2.5 percent)
+ (0.0038 × 750 lbs.)
- (0.32 × 12.8 sq. in.)
YG = 2.75
In the official USDA grading program the decimals are dropped and the yield grade is reported as 2.
In review, USDA yield grades estimate the quantity of edible meat from the major wholesale cuts--round, loin, rib and chuck.
Additional information regarding USDA quality and yield grades may be obtained by requesting Official United States Standards for Grades of Carcass Beef from the United States Department of Agriculture, Agricultural Marketing Service, Livestock and Seed Division, Standardization Branch, Room 2603 South Bldg., P.O. Box 96456, Washington, D.C. 20090-6456.
