Carcass grading

Compilation: Agricultural Education & Communication Department, CaliforniaCompilation: Agricultural Education & Communication Department, CaliforniaFor more veterinary stuff visit www.techyvety.comFor more veterinary stuff visit www.techyvety.com

CARCASS CARCASS GRADINGGRADING

Eric MorascaEric Morasca


CARCASS EVALUATIONCARCASS EVALUATION Evaluation of beef quality and composition is Evaluation of beef quality and composition is

important to cattle producers, meat packers and important to cattle producers, meat packers and retailers, and consumers. retailers, and consumers.

Consumers desire cuts of beef that are lean, Consumers desire cuts of beef that are lean, nutritious, and possess desirable eating nutritious, and possess desirable eating characteristics. characteristics.

Meat researchers have developed reliable methods Meat researchers have developed reliable methods for measuring the factors that influence eating for measuring the factors that influence eating characteristics and factors affecting yield of lean characteristics and factors affecting yield of lean cuts. cuts.

Using these evaluation techniques, producers and Using these evaluation techniques, producers and packers can produce and sell carcasses that meet packers can produce and sell carcasses that meet consumer demand. consumer demand.


THE PURPOSE OF EVALUATION IS THE PURPOSE OF EVALUATION IS TO ASSIST PRODUCERS IN:TO ASSIST PRODUCERS IN:

Producing high-quality beef carcasses Producing high-quality beef carcasses Producing high-yielding beef carcasses Producing high-yielding beef carcasses Identifying superior lines of breeding Identifying superior lines of breeding

stock stock Promoting a desirable, marketable Promoting a desirable, marketable

product. product.


QUALITY GRADEQUALITY GRADE Quality grades indicate the factors related to Quality grades indicate the factors related to

the sensory characteristics of tenderness, the sensory characteristics of tenderness, flavor, color, texture and juiciness. The flavor, color, texture and juiciness. The quality grade is intended to reflect the quality grade is intended to reflect the cooked product's overall acceptability. cooked product's overall acceptability.

The USDA quality grades for steer and heifer The USDA quality grades for steer and heifer carcasses are prime, choice, good, standard, carcasses are prime, choice, good, standard, and utility. These grades are determined by and utility. These grades are determined by balancing maturity and degree of marbling.balancing maturity and degree of marbling.


PRIME CHOICE SELECT


Within a maturity group, marbling within the Within a maturity group, marbling within the ribeye is the primary determinant of USDA ribeye is the primary determinant of USDA Quality Grade. Quality Grade.

Visual evaluation of marbling in the ribeye (at Visual evaluation of marbling in the ribeye (at the 12th rib cross-section) are related to the 12th rib cross-section) are related to differences in eating quality of beef. differences in eating quality of beef.

Beef cuts with high levels of marbling are Beef cuts with high levels of marbling are more likely to be tender, juicy and flavorful more likely to be tender, juicy and flavorful than the cuts with very low levels of marbling. than the cuts with very low levels of marbling.

Studies suggest that beef from carcasses Studies suggest that beef from carcasses grading at least USDA Select are likely to grading at least USDA Select are likely to acceptable in eating quality for most acceptable in eating quality for most consumers. consumers.


DARK CUTTERSDARK CUTTERSDark-cutting beef is not necessarily Dark-cutting beef is not necessarily

from older animals but can also result from older animals but can also result from cattle that were physiologically from cattle that were physiologically stressed before slaughter. stressed before slaughter.

Dark-cutting beef is highly discriminated Dark-cutting beef is highly discriminated against by consumers and retailers. against by consumers and retailers.

Dark-cutting beef may be reduced up to Dark-cutting beef may be reduced up to one full quality grade one full quality grade


MARBLINGMARBLING Marbling is fat within the muscle and is Marbling is fat within the muscle and is

evaluated in the rib eye between the 12th evaluated in the rib eye between the 12th and 13th ribs.and 13th ribs.

The 10 USDA degrees of marbling are The 10 USDA degrees of marbling are abundant, moderately abundant, slightly abundant, moderately abundant, slightly abundant, moderate, modest, small, slight, abundant, moderate, modest, small, slight, traces, practically devoid, and devoid. traces, practically devoid, and devoid.

Marbling has a strong correlation with the Marbling has a strong correlation with the juiciness and flavor of beef. juiciness and flavor of beef.


The age of a beef animal has a direct The age of a beef animal has a direct effect on tenderness of the meat it effect on tenderness of the meat it produces. produces.

As cattle mature, their meat becomes As cattle mature, their meat becomes progressively tougher. progressively tougher.

To account for the effects of the To account for the effects of the maturing process on beef tenderness, maturing process on beef tenderness, evaluations of carcass maturity are evaluations of carcass maturity are used in determining USDA Quality used in determining USDA Quality Grades. Grades.

There are five maturity groupings, There are five maturity groupings, Designated as A through E below. Designated as A through E below.


Approximate ages corresponding to Approximate ages corresponding to each maturity classification are: each maturity classification are:

A - 9 to 30 Months A - 9 to 30 Months B - 30 to 42 Months B - 30 to 42 Months C - 42 to 72 Months C - 42 to 72 Months D - 72 to 96 Months D - 72 to 96 Months E - More Than 96 Months E - More Than 96 Months


Approximate ages corresponding Approximate ages corresponding to each maturity classification to each maturity classification

are:are:


YIELD GRADESYIELD GRADESYield grades estimate the quantity or Yield grades estimate the quantity or

the amount of closely trimmed the amount of closely trimmed boneless retail cuts from the loin, boneless retail cuts from the loin, round, chuck and rib.round, chuck and rib.

There are five USDA yield grades, 1 There are five USDA yield grades, 1 through 5. through 5.

Yield grade 1 carcasses have the Yield grade 1 carcasses have the highest yield of retail cuts and yield highest yield of retail cuts and yield grade 5, the lowest grade 5, the lowest


PRIMAL CUTSPRIMAL CUTS


Yield grade Percent of carcass weight in boneless, uniformly trimmed retail cuts

1 more than 52.3

2 52.3 to 50.1

3 50.0 to 47.8

4 47.7 to 45.5

5 less than 45.5

The expected boneless retail yield from the round, loin, rib and chuck is as follows:


The USDA yield grade is based on The USDA yield grade is based on four factors: four factors:

Hot carcass weight (pounds) Hot carcass weight (pounds) Rib eye area at the 12th rib (square Rib eye area at the 12th rib (square

inches) inches) Adjusted fat thickness over the rib Adjusted fat thickness over the rib

eye at the 12th rib (inches) eye at the 12th rib (inches) Percent kidney, pelvic, and heart Percent kidney, pelvic, and heart

(percent of carcass weight). (percent of carcass weight).


FAT THICKNESSFAT THICKNESSThe amount of fat on a beef carcass has the The amount of fat on a beef carcass has the

greatest effect on the percent retail yield. greatest effect on the percent retail yield. As the percent fat increases, the percent As the percent fat increases, the percent

muscle decreases. muscle decreases. Fat thickness is measured at a point three-Fat thickness is measured at a point three-

fourths of the length of the rib eye fourths of the length of the rib eye (longissmus) muscle from the chine bone, (longissmus) muscle from the chine bone, perpendicular to the surface fat, at the 12th perpendicular to the surface fat, at the 12th rib. rib.

This measurement may be adjusted according This measurement may be adjusted according to the total amount of fat on the carcass. to the total amount of fat on the carcass.


Percentage of Kidney, Pelvic Percentage of Kidney, Pelvic and Heart Fat (KPH).and Heart Fat (KPH).

This is a subjective estimate of the This is a subjective estimate of the amount of fat surrounding the kidney amount of fat surrounding the kidney knob, and fat in the pelvic and knob, and fat in the pelvic and thoracic (heart) areas as a thoracic (heart) areas as a percentage of the carcass weight. percentage of the carcass weight.

As the percentage of KPH fat As the percentage of KPH fat increases, the percentage of retail increases, the percentage of retail cuts decreases. cuts decreases.

Percentage KPH fat normally ranges Percentage KPH fat normally ranges from 1.0 to 4.0 percent.from 1.0 to 4.0 percent.


Rib Eye Area.Rib Eye Area.The longissimus muscle is measured The longissimus muscle is measured

at the 12th rib by using a grid at the 12th rib by using a grid expressed in square inches, or a expressed in square inches, or a compensating polar planimeter, compensating polar planimeter, which measures a rib eye tracing. which measures a rib eye tracing.

Rib eye area is an indicator of Rib eye area is an indicator of carcass muscling; as rib eye area carcass muscling; as rib eye area increases, retail cut yield increases.increases, retail cut yield increases.


RIB EYE AREARIB EYE AREA


Hot Carcass Weight.Hot Carcass Weight. Generally, as carcass weight Generally, as carcass weight

increases, the percentage of retail increases, the percentage of retail cuts decreases slightly due to cuts decreases slightly due to increased fat deposition. increased fat deposition.

If only chilled carcass weight is If only chilled carcass weight is available, it can be adjusted to hot available, it can be adjusted to hot carcass weight by multiplying by 1.02 carcass weight by multiplying by 1.02 to correct for the evaporative weight to correct for the evaporative weight loss of the carcass in the cooler.loss of the carcass in the cooler.


Yield grades are calculated by Yield grades are calculated by using the following formula: using the following formula:

YG = 2.50 + (2.50 × Adjusted Fat YG = 2.50 + (2.50 × Adjusted Fat Thickness, inches) Thickness, inches) + (0.20 × Kidney, Pelvic and Heart Fat + (0.20 × Kidney, Pelvic and Heart Fat

%)%)+ (0.0038 × Hot Carcass Weight, lb)+ (0.0038 × Hot Carcass Weight, lb)- (0.32 × Rib eye area, sq. in.)- (0.32 × Rib eye area, sq. in.)


SOURCESSOURCEShttp://ianrpubs.unl.edu/beefhttp://muextension.missouri.eduhttp://www.bovineengineering.com

http://ianrpubs.unl.edu/beef

http://muextension.missouri.edu/

http://www.bovineengineering.com/