After the Beef Carcasses Are the Next Step Is Grading
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Beef Carcass Grading and Evaluation
thirty July 2007
By David R. Jones and William C. Stringer, Nutrient Scientific discipline and Nutrition Department, University Of Missouri Extension. Evaluation of beef quality and composition is important to cattle producers, meat packers and retailers, and consumers.
Consumers desire cuts of beefiness that are lean, nutritious, and possess desirable eating characteristics. Meat researchers have developed reliable methods for measuring the factors that influence eating characteristics and factors affecting yield of lean cuts. Using these evaluation techniques, producers and packers can produce and sell carcasses that meet consumer demand.
This guide provides data almost standard U.S. Section of Agriculture beef carcass yield and quality grading systems. Other useful and accurate evaluation procedures will as well exist introduced.
Beef carcass grading is divided into quality grading and yield grading.
Quality grading
Quality grades indicate the factors related to the sensory characteristics of tenderness, flavor, colour, texture and juiciness. The quality class is intended to reverberate the cooked product's overall acceptability.
The USDA quality grades for steer and heifer carcasses are prime, option, skilful, standard, and utility. These grades are determined by balancing maturity and degree of marbling.
Maturity refers to the physiological historic period of the live beast. Maturity in the carcass is determined by the degree of ossification (os development) of the separate chine bones (back bones) and the color and texture of the cut lean surface.
Cartilage changes into bone equally the animal matures. This process of ossification gain from the back toward the front portion of the vertebral column. The degree of ossification in the vertebral buttons near the thorax, which is the cavity containing heart, lungs, etc., is the most useful in evaluating maturity. Rib basic also become flatter and whiter every bit the animal matures.
Meat from immature animals is lighter colored and finer textured compared to older beef. More often than not, a fine-textured lean volition be more tender than a coarse textured lean. Carcass maturity is closely related to beefiness tenderness. As the animate being matures, changes in the connective tissue cause the meat to be less tender.
| The degrees of maturity are A, B, C, D and E. Age ranges for these maturity groups are approximately | |
| Maturity group | Age |
|---|---|
| A | 9 to 30 months |
| B | thirty to 42 months |
| C | 42 to 72 months |
| D | 72 to 96 months |
| E | more than 96 months |
Nighttime-cutting beefiness is non necessarily from older animals just can besides result from cattle that were physiologically stressed before slaughter. Dark-cutting beef is highly discriminated against past consumers and retailers. Night-cutting beef may be reduced up to i total quality class.
Marbling is fat within the muscle and is evaluated in the rib centre between the twelfth and 13th ribs. The 10 USDA degrees of marbling are arable, moderately abundant, slightly abundant, moderate, modest, small-scale, slight, traces, practically devoid, and devoid. Marbling has a potent correlation with the juiciness and flavor of beef.
Final quality grades are arrived at past a blended evaluation of maturity and marbling (Figure 1).
Effigy i Relationship between marbling, maturity, and carcass quality class
Yield grades
Yield grades approximate the quantity or the amount of closely trimmed boneless retail cuts from the loin, round, chuck and rib. There are five USDA yield grades, 1 through 5. Yield grade i carcasses have the highest yield of retail cuts and yield class v, the everyman.
The expected boneless retail yield from the circular, loin, rib and chuck is as follows:
| Yield grade | Percentage of carcass weight in boneless, uniformly trimmed retail cuts |
|---|---|
| ane | more than 52.3 |
| 2 | 52.three to 50.1 |
| 3 | fifty.0 to 47.8 |
| 4 | 47.7 to 45.v |
| 5 | less than 45.5 |
These yield figures are sometimes used in carcass show results as a mensurate of cutability.
Yield form besides can be used to predict the full retail cuts from a carcass or quarter.
| Total percent retail cuts (closely trimmed, semi-boneless) | |||
| Yield course | Carcass | Forequarter | Hindquarter |
|---|---|---|---|
| 1 | 82. 0 | 84.0 | 79. 9 |
| ii | 77 iv | 79.0 | 74.ix |
| 3 | 72 8 | 75.6 | 69.9 |
| 4 | 68.two | 71.four | 64.nine |
| v | 63.6 | 67.2 | 59 nine |
The USDA yield grade is based on 4 factors:
- Hot carcass weight (pounds)
- Rib eye expanse at the 12th rib (square inches)
- Adjusted fat thickness over the rib eye at the 12th rib (inches)
- Percent kidney, pelvic, and heart (percent of carcass weight).
These measurements are used in the official USDA formula as follows:
Yield grade = 2.five + [(2.fifty x adjusted fat thickness, inches) + 0.2 percent of kidney, pelvic, and heart + (0.0038 10 hot carcass weight, pounds) - (0.32 x area rib eye, foursquare inches)]
When computing yield grades, any decimal is dropped; yield grades are presented every bit whole numbers. Care and accuracy of these measurements are essential to derive reliable estimates of the cutability. The USDA grader, in practice, estimates the factors and uses a short-cutting formula.
Fat thickness
The corporeality of fat on a beef carcass has the greatest event on the percent retail yield. Equally the percent fat increases, the pct muscle decreases. Fatty thickness is measured at a bespeak 3-fourths of the length of the rib eye (longissmus) muscle from the chine bone, perpendicular to the surface fatty, at the 12th rib. This measurement may be adjusted co-ordinate to the full amount of fat on the carcass.
Rib eye area
Total foursquare inches of rib eye is used to judge muscular evolution of a beef carcass. This measurement can be taken objectively betwixt the twelfth and 13th rib. A calibrated transparent plastic grid placed over the rib eye is ordinarily used to determine the area.
An alternative method is to trace the perimeter of the rib center on acetate newspaper and calculate the area with a compensating planimeter, which is an musical instrument that measures area of irregularly shaped objects.
Hot carcass weight
Hot carcass weight, or 102 percent x chilled carcass weight, is the weight of the carcass after slaughter. The carcass weight has an changed effect on the percentage retail yield.
Kidney, pelvic, and heart fat
The amount of kidney, pelvic and heart fat is fat accumulated in the trunk cavity of the carcass. The weight is reported as a percent of the carcass weight. The range of kidney, pelvic and middle fat is 1 to 8 per centum (with a typical average of 3.five percentage).
Yield grades estimate the proportions of lean and fatty. Meat graders determine yield grades with fast, simple visual appraisals of fatty and muscle of the carcass. Fat thickness, hot carcass weight and rib centre expanse are objective measures with kidney, pelvic and middle fat being a subjective mensurate.
USDA grading is washed on a voluntary footing past the packer. The packer absorbs the cost. When a carcass is submitted for grading, it must be both quality and yield graded.
USDA grades should not be confused with the USDA inspection for wholesomeness.
Beef carcass evaluation
The purpose of beefiness carcass evaluation is to assist beef producers in:
- Producing high-quality beef carcasses
- Producing high-yielding beefiness carcasses
- Identifying superior lines of breeding stock
- Promoting a desirable, marketable product.
Improving the efficiency of beefiness cattle production is important to feeders, cow/calf ranchers and seed stock producers. Feeders tin can evaluate their feeding and direction practices with cutability scores or the pct or number of their cattle grading choice. cow/calf ranchers may apply grades to rank or performance-test their stock. Seed stock producers can ultimately use quality and yield grades in sire evaluation.
Some other guidelines or indexes that may be useful in beef carcass evaluation are a growth gene or loin eye index.
Growth factors can be used to express the composition of growth. Expressing the pounds of retail cuts per twenty-four hour period of age is i method.
This effigy is determined by this formula: pounds of trimmed retail cuts per twenty-four hours of age = (carcass weight 10 cutability) divided by age in days.
Case
A 600-pound carcass, 400 days old with a yield course 3 (50 percentage retail yield) produces 0.75 pounds of retail cuts per day of age:
(600 10 0.v) ÷ 400 = 0.75 pounds of retail cuts per day of age.
Loin eye area has been highly correlated to the percent muscle in a carcass. A goal of progressive beef producers is to produce cattle yielding at to the lowest degree 2 square inches loin heart area per 100 pounds of carcass.
Instance
A 550-pound carcass with a 12.5 square inch loin center would yield 2.27 square inches loin eye area per 100 pounds of carcass (12.5 ÷ v.v = ii.27 square inches loin middle area per 100-pound carcass).
Use of the USDA's Beef Carcass Information Service is a service designed to provide carcass information to breeders or others who don't own the animals at the time of slaughter. Cattle are ear tagged with USDA ear tags and upon slaughter the proper quality and yield grade data are forwarded to the purchaser of the ear tags. This is especially helpful to seed stock producers.
For information on source of ear tags and price of the service, contact Livestock Sectionalisation, Agricultural Marketing Service, U.S. Department of Agriculture, Washington, DC 20250.
Last updated: June 2007
Source: https://www.thecattlesite.com/articles/1081/beef-carcass-grading-and-evaluation
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