The Age of the Beef Animal and the Amount of Marbling in the Carcass Affect the:

Beef Grades and Carcass Information

24 April 2009

The U.S. Department of Agriculture (USDA) uses a dual grading organization for beefiness carcasses: a Yield Grade for estimating cutability and a Quality Grade as a comprehensive evaluation of factors that bear upon beef palatability, says the this Mississippi Land University Extension Service, study.

The USDA grades segregate carcasses into like categories based upon cutability and estimated palatability. Yield Grade identifies differences in cutability or yield of boneless, closely trimmed retail cuts from the round, loin, rib, and chuck. Quality Form indicates the relative desirability or expected palatability of the meat in a carcass or cut.

A highly-trained USDA employee known as a USDA grader or approved electronic instrumentation assign beefiness Yield Grades and Quality Grades to beef carcasses postharvest following a period of spooky typically ranging from 18 to 48 hours. Grading beef carcasses is optional.

Carcasses can receive both the Yield Grade and Quality Grade or only one of these grades. To have beefiness carcasses graded, a packing plant must request that carcasses be graded and must also pay for this service.

While not all beef carcasses from U.S. fed cattle are designated for grading, almost are now officially graded. More than 95 per cent of beef cattle harvested receive USDA grades.

More and more fed cattle are now sold by cattle feeders, to packers, in transactions such equally "class-and-yield" or "on-agrid" that require that all carcasses in such groups exist officially Yield Graded and Quality Graded. Some packers may likewise have their own in-house grades and premium/ disbelieve programs independent of USDA grades. Questionnaires from the 2005 National Beefiness Quality Audit suggested that more than half of the fed cattle marketed in the U.Southward. are at present sold "on the grid" or "in the beef." In improver, the per centages of source and age verified cattle are small just increasing.

Carcass Traits

Yield Grades and Quality Grades are determined from observing and measuring specific carcass traits. Additional carcass traits not used in the official USDA grading organisation, such as tenderness, also touch beef end product. Individual traits impact carcass grades and product value in dissimilar ways. The post-obit department lists and discusses private carcass traits. Data from the Mississippi Farm to Feedlot program from 1993 through 2007 are included where advisable. The Farm to Feedlot program facilitates retained ownership of Mississippi feeder cattle through the feeding phase. The program provides feedlot functioning and carcass data, which can be linked to individual sires and/or cows, to assist in genetic choice for improved operation.

Hot Carcass Weight

Hot carcass weight (HCW) is the hot or unchilled weight of a beef carcass later on harvest and removal of the hide, head, alimentary canal, and internal organs. Information technology is sometimes reported as carcass weight. Carcass weight is the virtually important gene in determining carcass value when cattle are sold. Regardless of how cattle are marketed, whether on a dressed-weight basis or on a value-based grid, carcass value is ever tied to the weight of the carcass.

Therefore, in many cases, a heavier-weight carcass may have a greater total value than a lighter weight carcass because of the difference in total pounds, even if the lighter carcass is more valuable on a per-pound ground. Hot carcass weight is as well used in Yield Grade calculations. Generally, the per centage of retail production decreases as cattle increase in weight because of increased fat deposition, simply this depends on the growth phase of the animal.

Packers monetarily discount heavyweight and lightweight carcasses that do not fit their specifications. Generally, equally carcass weights motion further away from baseline specifications, discount levels increase.

Large fluctuations in carcass weights create challenges during harvesting and processing. Heavy carcasses can pause or harm overhead rail systems in packing plants, and light carcasses may be too short for stationary equipment used in carcass fabrication.

Additionally, wholesale beefiness cuts that are outside desired size ranges are difficult to manage and market in a boxed-beefiness system.

The National Beefiness Quality Audit outlined a range of 650 to 850 pounds every bit an manufacture target for carcass weight. Carcass size is genetically influenced and tin can be inverse with an accent on frame size and growth rate in breeding decisions. Management of days on feed, implant regimes, and feeding programs can also be changed to touch carcass weights. Mississippi Farm to Feedlot program data show that the 15-year boilerplate for hot-carcass weight was 750 pounds.

Dressing per centage

Dressing per centage Case

Dressing per centage is hot carcass weight as a per centage of the live weight of the animal at harvest. Information technology typically ranges from 60 to 64 per cent for the majority of fed cattle and averaged 64 per cent for the Mississippi Subcontract to Feedlot program cattle from 1993 through 2007. To summate dressing per centage, carve up hot carcass weight by animal alive weight. The result is a per centage. For example, if a 1200-pound steer produces a 768-pound carcass, the dressing per centage is 64 per cent (768 ÷ 1200 ten 100 per cent = 64 per cent). Similarly, animal live weight times the dressing per centage yields the carcass weight.

Ribeye area (REA) is an indicator of the amount of lean muscle associated with a carcass. As the REA increases, the amount of muscle in a carcass increases. It is an important cistron in determination of Yield Class. As ribeye expanse increases, Yield Grade tends to amend.

Ribeye Area

Rib Eye Exposed for Measurement

Ribeye expanse is determined past measuring the area of the longissimus dorsi (ribeye) musculus exposed by cutting or "ribbing" the carcass between the twelfth and 13th ribs. Ribeye expanse is expressed in square inches and is oftentimes determined using a grid device, analysis of ribeye tracings, or most recently, electronic vision instruments that are basically computerized cameras.

Within the beef industry, ribeye size varies profoundly. Both excessively pocket-sized and excessively large ribeyes are quality challenges for the beef industry. An optimum range for ribeye area is eleven to 15 sq. in. Ribeye surface area targets should exist approximately 1.6 to i.8 sq. in. per 100 pounds of carcass weight. Results from the Mississippi Farm to Feedlot programme show that ribeye area averaged 12.95 sq. in., and ribeye surface area per 100 pounds of carcass weight (cwt) averaged i.74 sq. in.

Fat Thickness

Fat Thickness Measurement

Fat thickness (rib fat or dorsum fat) is a measure of external fatty thickness on a carcass. External fat is the most important determinant of retail yield. Fatty thickness is measured at a point ¾ of the length of the longissimus dorsi musculus from the carve up chine bone.

As fatty thickness increases, cutability and per centage of retail product subtract, resulting in less desirable Yield Grades. Cutability is the per centage yield of closely trimmed, boneless retail cuts. Excessively low amounts of external fat on a beef carcass are undesirable, every bit well. This tin can increase the risk of common cold shortening (chilling of the carcass too quickly, leading to increased toughness). An optimum range for fat thickness is 0.ii to 0.v inches. Mississippi Subcontract to Feedlot program carcass back fat thickness averaged 0.48 inches over 15 years of the program.

Internal Fat

Kidney, pelvic, and heart (KPH) fat is also called internal fat. Internal or KPH fat is expressed as a per centage of hot carcass weight and is used in Yield Grade determination. The per centage of retail product yield decreases equally KPH fat increases.

Intramuscular Fat

Intramuscular fat (Imf) is frequently called marbling. Marbling refers to the flecks of fatty inside the muscle tissue. Sufficient marbling is important for beef tenderness, juiciness, and flavor. Degree of marbling is the principal factor determining Quality Class. For official grading purposes, marbling is assessed in the longissimus dorsi musculus exposed between the 12th and 13th ribs. Nine degrees of marbling are recognized by the USDA Grade Standards. These nine marbling scores and their common abbreviations are listed below.

Abundant 00-99 (AB)
Moderately abundant 00-99 (MAB)
Slightly abundant 00-99 (SLAB)
Moderate 00-99 (MD)
Pocket-size 00-99 (MT)
Small 00-99 (SM)
Slight 00-99 (SL)
Traces 00-99 (TR)
Practically devoid 00-99 (PD)

Each marbling score is divided into 100 subunits. Superscripts ranging from 00 (to the lowest degree amount of marbling) to 99 (greatest amount of marbling) are assigned within each marbling score. Average marbling score over fifteen years of the Mississippi Farm to Feedlot program was Pocket-sized, with the trend being toward increasing marbling score.

Maturity

Maturity is another cistron affecting carcass Quality Grade. It is subjectively evaluated because chronological age (age in months) of a beefiness animal is not ever known at harvest. Therefore, physiological estimators of age are used to evaluate carcass maturity.

Physiological historic period may not exist the same as the actual animal historic period. The physiological maturity of a carcass is adamant by evaluating the size, shape, and ossification of bone and cartilage (especially the split chine bone) and the color, texture, and compactness of the lean tissue exposed at cut betwixt the 12th and 13th rib. Lean colour becomes darker and texture becomes coarser with historic period. Factors other than age can alter lean color and texture, so nearly of the accent on maturity evaluation is placed on observation of bone characteristics and cartilage ossification.

To approximate maturity, a USDA grader evaluates the cartilage associated with the backbone (spinal column) and the colour and shape of the ribs. When a beef fauna is harvested, the carcass is split downwards the spinal column. When the carcass is dissever in half, the grader can evaluate cartilage associated with the spinal column and the shape and color of the ribs. At the dorsal (behind) end of each vertebra is a department of cartilage, which is referred to as the cartilaginous tips or buttons. As cattle age, these tips ossify or change from soft, pearly-white cartilage to hard, porous bone.

Maturity is then estimated based on the status of these buttons and the degree to which they are ossified. The rib basic are quasi round with a red, youthful advent in immature cattle. As cattle age, the ribs flatten out and develop a white appearance.

Carcass maturity is scored using letters A through E, with A's beingness the least mature and Eastward'southward being the nearly mature. Carcasses displaying advanced skeletal maturity are referred to equally "difficult bones," and associated price discounts normally apply.

USDA Maturity Scores and Associated Cattle Ages
A	nine to 30 months (two and a one-half years)
B	thirty to 42 months (2 and a half to 3 and a half years)
C	43 to 72 months (three and a half to 6 years)
D	73 to 96 months (6 to 8 years)
East	97 months or more than (greater than 8 years)

Tenderness

Inadequate tenderness of beef was cited in the 2005 National Beef Quality Audit as one of the superlative quality challenges facing the beef manufacture.

Although tenderness is non used in Quality Class or Yield Grade calculations, it plays an essential part in consumer satisfaction. Tenderness is considerately measured with a Warner-Bratzler shear force device. A practiced industry target for tenderness is a Warner- Bratzler shear forcefulness value below eight pounds.

Adequate tenderness levels depend in function on where and how the production volition exist marketed. Currently there is no piece of cake way to appraise tenderness in making beef purchasing decisions, so restaurants often base of operations their purchasing decisions on Quality Grade instead. Many food service establishments, specially fine-dining establishments, seeking a good eating experience for their customers recognize that tenderness is an of import component of the experience.

Tenderness is impacted by cattle genetics, preharvest cattle management, and postharvest factors. There is likely to exist increased emphasis on choice of cattle for beef tenderness as choice tools become available and as tenderness level reporting develops. Beefiness cattle breed associations are beginning to address tenderness equally a trait of interest in national cattle evaluations.

Research efforts are under way to identify genetic markers for tenderness and develop selection tools based on this information. Many preharvest management factors bear on tenderness as well include animate being nutrition, stress, and wellness. Postharvest factors impacting tenderness include carcass aging time, carcass electrical stimulation use, postmortem pH, cooking temperature, cooking method, and degree of doneness.

USDA Beef Carcass Grades

USDA Yield Grade

The USDA Yield Grades classify carcasses for differences in cutability or yield of boneless, closely trimmed retail cuts from the round, loin, rib and chuck. The five Yield Grades are numbered 1 through five. Carcasses in Yield Grade 1 have the highest cutability or per centage of retail production, while carcasses in Yield Grade 5 have the everyman cutability or per centage of retail product. Mississippi Farm to Feedlot program cattle averaged Yield Grade 3 over a xv-year menstruation.

The Yield Grade of a beef carcass is determined by because four characteristics: (i) the corporeality of external fatty (back fat), (ii) the amount of KPH fat, (3) the area of the ribeye muscle, and (4) the hot carcass weight.

Yield Grades are based on the post-obit equation: Yield Course = 2.fifty + (2.5 x adjusted fat thickness, inches) + (0.2 x per centage kidney, pelvic and center fat) + (0.0038 x hot carcass weight, pounds) – (0.32 10 area of ribeye, foursquare inches)

US Beef Quality Grades

Source USDA, 2008.

Comparison past Yield Grade of federally inspected beef carcasses in 2007

Numerical Yield Grades calculated using this equation are rounded down to the nearest whole number for assignment of a singled-out Yield Grade from 1 to v. For example, a beefiness carcass with a calculated Yield Course of 2.98 would be classified as Yield Grade ii, non Yield Grade 3. Therefore, it is possible for a change in a characteristic influencing Yield Form to change the calculated Yield Grade in terms of decimals every bit indicated in the following table while not changing the actual assigned Yield Grade of ane, ii, three, 4, or 5.

Chracteristic affecting Yield Grade	Change in characteristic	Resulting change in numerical Yield Grade
Effects of various factors on beefiness carcass Yield Grade
Fat thickness	Increase	Increase
per cent of kidney, pelvic, and heart fat	Increase	Increase
Carcass weight	Increase	Increase
Ribeye expanse	Increase	Subtract

Because of the scale and speed of modern packing plants (many plants grade 300 to 400 beef carcasses per hr), instead of measuring these factors and using the equation to determine Yield Grade, a USDA grader will read the carcass weight noted on a tag practical to the carcass past the packing plant; estimate ribeye surface area, external fatty, and KPH fat; so assign a Yield Grade based on these values.

USDA Quality Grade

Quality Grades evaluate factors that affect beef palatability (eating quality and desirability). Marbling and carcass maturity (including bone characteristics and the color, firmness, and texture of the exposed lean on the cutting surface between the 12th and 13th rib) determine Quality Form. A meliorate Quality Form is achieved with more marbling and lower carcass maturity. Notation the differences in marbling at the same level of maturity between the different Quality Grades in the above tabular array and within a Quality Grade in the following table:

Effects of maturity and marbling on beefiness carcass Quality Grade1

1 Assumes that firmness of lean is completely developed with the degree of marbling and that the carcass is not a "dark cutter."
2 Maturity increases from left to right (A through Eastward).
three The A maturity portion is the simply portion applicable to bullock carcasses.

Beefiness Quality Grades are typically divided into thirds or halves for improved segregation of beefiness carcasses. Meat judging, carcass evaluation, and value-based marketing programs utilise these subdivisions. The Prime Form is divided into thirds (High, Boilerplate, and Low), and the Choice Form is also divided into thirds (High, Boilerplate, and Depression). The Select Grade is divided into halves (High and Low), and the Standard Grade is besides separated into halves (High and Depression).

Symbols used to designate these Quality Grade divisions are: + (high), o (average) and – (low). For example, Choice– indicates the lower one-third of the Selection Class. A "No Roll" category refers to all carcasses that do not come across the requirements for the USDA Select Grade and would likely grade USDA Standard if graded. A grade stamp is not rolled on these carcasses. Bull beef is not Quality Graded, and moo-cow beef is not eligible for the Prime number Grade. In addition, Commercial, Cutter and Canner grades are non applicable to bullock beefiness.

Mississippi Farm to Feedlot plan cattle averaged Select + over fifteen years, with a trend toward increasing Quality Grade. The per centage of these cattle grading Option – or better was 43 per cent and also displayed an increasing trend.

Carcass Defects

Dark Cutters

Night-cutting meat is characterized by a colour range from dark cherry to nearly black and has both a glutinous texture and a high water-belongings capacity. Dark-cut beef results from low muscle glycogen at the time cattle are slaughtered. Glycogen depletion in muscles of cattle tin be caused past strenuous muscular activity, stress-induced adrenalin secretion, and severe energy brake for several days before slaughter. Highly excitable cattle are more likely to produce dark cutter carcasses than calmer cattle.

The greatest problem with dark-cutting beefiness is consumer rejection considering of its color. The quality of dark-cutting beefiness is lower than normal. Information technology has significantly shorter shelf-life than normal beef and greater h2o-holding capacity, which are more conducive to bacterial growth. For these reasons, dark-cutting beef is severely discounted. The 2005 National Beef Quality Inspect reported that 1.five per cent of beefiness carcasses were dark cutters.

Blood Splash

"Blood splash" describes localized hemorrhaging (bleeding) within the muscles of a beefiness carcass. This condition results when the capillaries in the muscles rupture considering of abnormally high blood force per unit area before exsanguination (blood draining). Lengthy delays between stunning and sticking during harvest may cause this. The incidence of claret splash reported in the 2005 National Beef Quality Audit was1.7 per cent.

Calloused Ribeyes

"Calloused" ribeyes are the result of steatosis of longissimus muscle. Connective and fatty tissues can spread into areas of muscle, creating a callus or department of fatty tissue inside the muscle. The causes of muscular steatosis are unknown, but strenuous muscle exertion may exist involved. The 2005 National Beef Quality Audit reported a calloused ribeye incidence of 0.3 per cent.

Bruises

Trim loss is most often from fecal contamination but can occur from deep tissue bruising or astringent abscesses. Trim loss from bruising can touch carcass value, particularly when loftier-value sections of the carcass are involved. Trimming that damages the major muscle groups of the wholesale round, loin, rib, or chuck is a "major" defect.

The 2005 National Beef Quality Audit revealed that 35.ii per cent of beef carcasses were bruised. This was down from 46.7 and 48.four per cent in the 1995 and 2000 audits. Nearly one-third of bruises in 2005 appeared on the loin. Following Beef Quality Assurance guidelines, such as adhering to recommended injection site locations, dehorning, and treatment animals properly, can assistance minimize bruising and resulting trim loss.

Organ Condemnations

In addition to being paid for the value of a beefiness carcass, producers are paid a drop credit that includes the value of hibernate, head, organs, and claret. Variety meats are produced from carcass offal such as livers, hearts, and tongues. Condemnations of these products reduce the value of harvested beef animals.

The 2005 National Beefiness Quality Audit showed that 24.vii per cent of livers were condemned, an improvement from the 30.3 per cent of livers condemned according to the 2000 Audit. Liver condemnations were primarily from abscesses and liver flukes. Lung condemnation incidence was 11.5 per cent. Pneumonia was the leading crusade of lung condemnations. Tripe condemnation occurred at a rate of 11.half-dozen per cent. The main cause of tripe condemnation was contagion with metallic objects such as nails, cotter pins, and wire. In addition, ix.7 per cent of tongues were condemned. Whole carcass condemnations were non found.

Conclusions

Carcass uniformity and consistency vary greatly amid beefiness cattle. Gender differences likewise be in carcass grades.

The 2005 National Beef Quality Audit identified the top 10 greatest quality challenges facing the beef industry. Many of these quality challenges tin be addressed by using beef carcass information for improved genetic selection practices. They can too be affected past making cattle direction decisions with the quality and value of the beefiness finish production in mind.

Using this data, beef cattle producers tin accept the following actions to improve carcass value:

Improve cattle genetics
Increase record keeping
Increase individual animal identification
Improve brute handling and transportation practices
Collect and utilize carcass information
Follow Beefiness Quality Assurance guidelines

Carcass traits are important in determining Beef Yield Grades and Quality Grades. They are an important consideration for beef cattle producers in cattle selection and direction, peculiarly when cattle ownership is retained through harvest and cattle are marketed on value-based carcass grids. The 2005 National Beef Quality Audit indicated that 62 and 42 per cent of branded beef programs had specifications for marbling and Yield Grade, respectively. Producers who provide carcass information to potential buyers position themselves to be rewarded for producing a quality production. For more than information on beefiness grading, carcass information, or related topics, contact an part of the Mississippi Land University Extension Service.

Apirl 2009

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Source: https://www.thebeefsite.com/articles/1961/beef-grades-and-carcass-information