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AMS - Beefcarcassrevisions

From: Lawrence, Ty <tlawrence@mail.wtamu.edu>

Sent: Thursday, November 13, 2014 12:34 PM

To: Yates, Lawrence - AMS

Cc: AMS - Beefcarcassrevisions

Subject: RE: USDA Seeks Comments to Revise the Standards for Grades of Carcass Beef

Follow Up Flag: Follow up

Flag Status: Flagged

Lawrence, 

 

Thank you for the opportunity to comment on the potential for revisions of the beef grading standards. 

 

The beef grading system historically has provided the market an ability to discern broad finish and red meat yield

differences and to merchandize beef accordingly.  For many years, the individual grading performance of the cattle did

not directly impact revenue as cattle were largely marketed to the packer via either a live or hot carcass weight bid.  

However, in the most recent decade, the market has transitioned to an ever increasing volume of formula or value‐

based sales in which the cattle are sold as individually graded carcasses.  This change in market structure has led many

cattle feeders to become increasingly aware of the grading system and its ability and inability to differentiate true

carcass value.  Moreover, also in the last decade, the industry has shifted from exclusive human grading to partial

human grading and/or exclusive instrument grading with human oversight.  The following comments are based upon the

opportunities I have had to conduct extensive research with respect to the beef grading system.  

Quality grading

The quality grading system was built upon a basis of subjectively evaluated intramuscular fat quantity and subjectively

evaluated vertebral column ossification with an adjustment for lean color.   

The association between marbling level and palatability has been well studied and the literature suggests that marbling

accounts for up to 10‐15% of the variation in overall palatability.  In contrast, the association between maturity score

and palatability is weaker, more variable, and less indicative of palatability variation.  The bulk of meat science literature

indicates that other factors inclusive of sarcomere length, collagen quantity and quality, ultimate pH, calpain to

calpastatin ratio, and postmortem aging duration are equally important as marbling in quantifying muscle to muscle and

carcass to carcass palatability variation.  That being said, no practical method currently exists to discern those individual

animal and muscle differences at the speed of commerce for any of those traits...other than marbling.   

The historical assessment of marbling via subjective human evaluation has resulted in considerable bickering and

consternation amongst cattle feeders, beef processors, and the USDA‐AMS grading service.  Evaluation of marbling is

standardized in the U.S. (and Canada) via marbling cards.  When discrepancies have arisen in the marbling level of an

individual animal, those involved could look to the marbling cards for an industry standard in which to base judgment.  

In recent years, with the advent and application of instrument grading, much of the consternation surrounding opinions

in absolute marbling scores of carcasses has eroded.   

I am a supporter of utilizing marbling scores to differentiate level of finish and to minimize market and brand disruption.

Assessing the extent of vertebral column ossification is fraught with issues.  The evaluation itself does not have a visual

standard known to the industry.  Myself, and many other professors and instructors, have pooled pictures of our

opinions of A, B, C, D, and E carcasses for use in teaching the art of grading to the next generation.  However, an industry

standard has never existed.  Rather, the official grading standards utilize vague terms “...have slightly red and slightly

soft chine bones and cartilages on the ends of the thoracic vertebrae that have some evidence of ossification.  In
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addition, the sacral vertebrae are completely fused and the cartilages on the ends of the lumbar vertebrae are nearly

completely ossified. The rib bones are slightly wide and slightly flat and the ribeye muscle is light red in color and is fine in

texture” to describe how carcass maturity is to be assessed.  As many opinions exist for “slightly red”, “slightly soft”,

“some ossification”, “nearly completely ossified”, “slightly wide” and “slightly flat” as persons asked.  This standard has

not lent itself to a true standard and has created confusion and frustration amongst both cattle feeders and beef

processors.   

Beyond subjective assessment without a standard, the maturity classification system has a built‐in sex bias.  Ossification

of bone and more specifically the cessation of chondrocyte proliferation is a physiological process that is controlled by

the hormone estrogen.  A bias in ossification rate and extent exists in our current grading system because the majority

of the male population is marketed as a castrate (steer) and the majority of the female population is marketed as an

intact (heifer).  Steers will ossify at an extremely slow rate after removal of the testes because their only estrogen source

is minimal amounts produced by the adrenal glands and fat cells as well as that likely placed in their ear in the form of a

growth promoting implant.  Heifers will ossify at a rate much greater than steers due to their regular cycling.  Heiferettes

and cows will typically exhibit more advanced ossification from the large amounts of estrogen produced by the placenta

during gestation.  A final consideration for maturity assessment is the current inability of instrument assessment.   

If the beef industry desires a method of maturity assessment, I suggest consideration of dental classification.  Since

January 2004, the assessment of permanent incisors present at harvest has been utilized to segregate beef carcasses

into two categories (<30 month, >30 month).  The currently applied assessment is very objective (yes/no) – an animal

does or does not have 3 permanent incisors.  Moreover, cattle will have 0 – 8 permanent incisors; a standard can easily

be constructed for widespread industry application using the number of permanent incisors.  In contrast to ossification,

dental classification can be assessed in the live animal.  Dental eruption rate is not without fault, and is known to contain

bias as well.  Rather than a sex bias, rate of dental eruption is influenced by nutrition, particularly malnutrition.  

Additionally, similar to ossification maturity assessment, dental classification is not strongly linked to palatability.   

Yield grading

The yield grading system is out‐of‐date and the application of a yield grade equation created with cattle harvested in the

1950’s is not representative of the majority of the current cattle population.  Moreover, the yield grade was intended to

estimate the percentage of boneless closely trimmed rib‐loin‐chuck‐round.  Closely trimmed was 1⁄2 ‐ inch of fat during

the 1950’s; today’s standard at the retail case is largely of product trimmed to the blue...or to the red.  Additionally, the

current market suggests that 60% of the beef consumed is in the form of ground beef – our yield grade equation does

not directly account for beef trimmings within a carcass.  Furthermore, the classification of all carcasses into 5 broad

yield categories does little to differentiate true red meat yield.  For example, an instrument graded carcass could have a

yield grade of 3.99 and not receive a discount.  If the same carcass was graded as a 4.00, it would typically receive a

discount of $6‐15/cwt for a true fabrication yield change of approximately 0.0176%.  The true yield of carcasses and thus

value should be more finitely estimated along a linear continuum.

Data that we have published suggests the assumed HCW to REA relationship (i.e. 600 pound carcass shall have 11.0 in2

ribeye) is noticeably different in slope and shape (quadratic vs linear) from data observed in a large population of

carcasses.  Other data we published suggests that instrument grading technology could be reprogrammed to capture

new lean and fat indicators to improve accuracy of assessing red meat yield.  One of the most troubling findings we have

published was the relationship (or lack of) between calculated yield grade and red meat yield of calf‐fed Holstein steers.  

This population of cattle is approaching 15% of the fed beef industry and our data suggests that assessment of yield

grade does not discern true red meat yield of fed Holstein steers.

If the beef industry desires to assess red meat yield, I suggest either development of a new equation using instrument

grading to its fullest capacity or investigation of new methodologies (i.e. bioelectrical impedance, electromagnetic

conductivity, x‐ray).

Ty Lawrence, Ph.D.

West Texas A&M University
3

Associate Professor of Animal Science

Director, Beef Carcass Research Center

Department of Agricultural Sciences

WTAMU Box 60998

Canyon, TX 79016‐0001

Office: 806‐651‐2560

Mobile: 806‐681‐9861

BCRC: 806‐651‐2275 or 2278

Meat Lab: 806‐651‐2565

Email: tlawrence@mail.wtamu.edu

 

 

From: Yates, Lawrence - AMS [Lawrence.Yates@ams.usda.gov] 

Sent: Monday, August 18, 2014 4:36 PM 

To: Yates, Lawrence - AMS 

Subject: USDA Seeks Comments to Revise the Standards for Grades of Carcass Beef

Your suggestions and comments in regards to possible revisions to the United States Standards for Grades of Carcass

Beef would be greatly appreciated.  Comments and proposed changes may be sent by email to

beefcarcassrevisions@ams.usda.gov or by mail to:  

  

Beef Carcass Revisions

Standardization Branch

LPS Program, AMS, USDA,

1400 Independence Ave., SW., STOP 0258

Washington, DC 20250

  

I have attached the pertinent documents for your convenience.  These are also available at U.S. Standards for Grades of

Carcass Beef.

  

Thank you.

  

Sincerely,   

  

Lawrence Yates, Ph.D. │ Livestock Marketing Specialist

Standardization Branch ‐ Quality Assessment Division

USDA.MRP.AMS.LPSP │ 6909 S. 152nd Street │ Omaha, NE 68138 USA

Lawrence.Yates@ams.usda.gov │ (402) 621.0836

  

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