United States

Department of

Agriculture

Agricultural 

Marketing

Service

Livestock

and Seed

Division

United States Standards

for Grades of

Pork Carcasses

Effective date January 14, 1985
1

United States Standards for Grades of Pork Carcasses

The following is a reprint of the Official United States Standards for the Grades of Pork Carcasses

promulgated by the Secretary of Agriculture under the Agricultural Marketing Act of 1946 (60

Stat. 1087; 7 U. S. C. 1621-1627) as amended and related authority in the annual appropriation

acts for the Department of Agriculture. The standards are reprinted with amendments effective

January 14, 1985.

Development of the Standards

Tentative standards for grades of pork carcasses and fresh pork cuts were issued by USDA in

1931. These tentative standards were slightly revised in 1933.

New standards for grades of barrow and gilt carcasses were proposed by USDA in 1949. 

These standards represented the first application of objective measurements as guides to grades

for pork carcasses. Slight revisions were made in the proposed standards prior to adoption, as the

Official United Standards for Grades of Barrow and Gilt Carcasses, effective September 12, 1952.

The official standards were amended in July 1955, by changing the grade designation Choice

No. 1, Choice No. 2, and Choice No. 3 to U.S. No. 1, U.S. No. 2, and U.S. No. 3, respectively. 

In addition, the backfat specifications were reworded slightly to reflect the reduced fat thickness

requirements and to allow more inform interpretation of the standards.

On April 1, 1968, the official standards were again revised to reflect the improvements made

since 1955 in pork carcasses. The minimum backfat thickness requirement for the U.S. No. 1

grade was eliminated and a new U.S. No. 1 grade was eliminated and a new U.S. No 1 grade was

established to properly identify the superior pork carcasses then being produced . The former No.

1, No. 2, No. 3 grades were renamed No. 2, No. 3, and No. 4, respectively. The former Medium

and Cull grades were combined and renamed U.S. Utility. Also, the maximum allowable

adjustment for variations-from-normal fat distribution and muscling were changed from one-half

to one full grade to more adequately reflect the effect of these factors on yields of cuts.

In addition, the text of the “Application of Standards” section was reworded to more clearly

define the grade factors and clarify their use in determining the grade.

On January 14, 1985, the barrow and gilt carcass grade standards were once again updated to

reflect improvements in pork carcasses and changes in pork slaughter industry since 1968. A

1980 grade survey found that over 70 percent of the pork carcasses being produced were in the

U.S. No. 1 grade, indicating a large amount of variation in yield which was not being accounted

for by the grades. The changes simplified the standards by basing the grade on the backfat

thickness over the last rib with a single adjustment for muscling. In addition, the grade lines were

tightened to more adequately sort the pork carcasses being produced among several grades. 

Some minor changes in the wording of the quality requirements were also made.
2

§4.131 Scope. 

 These standards for grades of pork are written primarily in terms of carcasses. However,

they also are applicable to the grading of sides. To simplify the phrasing of the standards, the

words “carcass” and “carcasses” are used also to mean “side” or “sides.” 

§4.132 Bases for pork carcass standards. 

The official standards for pork carcass grades provide for segregation according to (a) class,

as determined by the apparent sex condition of the animal at the time of slaughter, and (b) grade,

which reflects quality and the expected yield of lean cuts in the carcass. 

 

§54.133 Pork carcass classes. 

The five classes of pork carcasses, comparable to the same five classes of slaughter hogs, are

barrow, gilt, sow, stag, and boar carcasses. The official standards provide for the grading of

barrow, gilt, and sow carcasses. Grades are not provided for stag and boar carcasses. 

 

§54.134 Application of standards for grades of barrow and gilt carcasses. 

(a) Grades for barrow and gilt carcasses are based on two general considerations: (1) Quality

-- which includes characteristics of the lean and fat, and (2) the expected yield of the four lean

cuts (ham, loin, picnic shoulder, and Boston butt). 

(b) Two general levels of quality are recognized: (1) Acceptable and (2) unacceptable. The

quality of the lean is best evaluated by a direct observation of its characteristics in a cut surface,

and when a cut surface of a major muscle is available, this shall be used as the basis for the quality

determination. Quality of the lean is described in terms of characteristics of the loin eye muscle at

the 10th rib. When this surface is not available, other exposed major muscle surfaces can be used

for quality determinations based on the normal development of the characteristics in relation to

those described for the loin eye muscle at the 10th rib. When a major muscle cut surface is not

available, the quality of the lean shall be evaluated indirectly based on the quality-indicating

characteristics that are evident in the carcass. These include firmness of the fat and lean, amount

of feathering between the ribs, and color of the lean. The degree of external fatness, as such, is

not considered in evaluating the quality of the lean. However, a pork carcass must have a belly

with sufficient thickness to be suitable for bacon production to be considered acceptable in

quality. Belly thickness is determined by an overall evaluation of its thickness, with primary

consideration being given to the thickness along the navel edge and the thickness of the belly

(flank) pocket. 

(c) For barrow and gilt carcasses with the minimum acceptable lean quality, the cut surface of

the loin eye muscle at the 10th rib will be slightly firm, have a slight amount of marbling, and be

grayish pink to moderately dark red in color. For intact carcasses, minimum acceptable quality of

lean is indicated by a slight amount of feathering, fat that is slightly firm, and lean that is slightly

firm and grayish pink to moderately dark red in color. The belly is at least slightly thick with a
3

minimum of 0.6 inches of thickness at any point. Barrow and gilt carcasses which meet or exceed

these minimum quality requirements are eligible for one of the four numerical grades which reflect

expected yields of four lean cuts. Barrow and gilt carcasses with unacceptable quality are graded

U.S. Utility. Also graded U.S. Utility are carcasses which have soft and/or oily fat. 

(d) Barrow and gilt carcasses which have indications of acceptable lean quality and acceptable

belly thickness are placed in one of four grades, denoted by numbers 1 through 4. These grades

are based entirely on the expected carcass yields of the four lean cuts, and no consideration is

given to a development of quality superior to that described as minimum for these grades. The

expected yields of the four lean cuts for each of these four grades are shown in Table 1. 

TABLE 1 -- Expected Yields of the Four Lean Cuts, by Grade, Based on Chilled Carcass Weight1

Grade Yield

U.S. No. 1 ....................................... 60.4 percent and over.

U.S. No. 2 ....................................... 57.4 to 60.3 percent.

U.S. No. 3 ....................................... 54.4 to 57.3 percent.

U.S. No. 4 ....................................... Less than 54.4 percent.

These yields will be approximately 1 percent lower if based on hot carcass weight. 1

The yields shown in Table 1 are based on cutting and trimming methods used by the U.S.

Department of Agriculture in developing the standards. (These cutting and trimming methods

may be obtained from the Livestock Division, Agricultural Marketing Service, U.S. Department

of Agriculture, Washington, DC 20250.) Other cutting and trimming methods may result in

different yields. For example, if more fat is left on the four lean cuts than prescribed in the USDA

methods, the yield of each grade will be higher than indicated. However, such a method of

trimming, if applied uniformly, should result in similar differences in yields between grades. 

(e) The grade of a barrow or gilt carcass with acceptable lean quality and belly thickness is

determined by considering two characteristics: (1) The backfat thickness over the last rib, and (2)

the degree of muscling (thickness of muscling in relation to skeletal size). 

(f) The amount of external fat on a barrow or gilt carcass is the major factor affecting the yield

of lean cuts. As the amount of external fat increases, the yield of lean cuts decreases. An

accurate evaluation of the amount of external fat may be made by measuring the backfat thickness

at one or more points on the carcass. In grading barrow and gilt carcasses, the amount of external

fat is considered by measuring the backfat thickness (including skin) over the last rib,

perpendicular to the skin surface. The actual measurement, without adjustment, is used for the

grade determination, except for carcasses from which the skin has been smoothly and evenly

removed, which will have one-tenth inch added to the measurement to compensate for the loss of

the skin. Carcasses which have had the skin removed in a rough, uneven manner, or which have

had more than a slight amount of trimming to remove bruised or otherwise damaged parts, are

ineligible for grading. The yield of four lean cuts from skinned carcasses will be higher than

indicated in Table 1. Pork carcasses with average fatness will usually have 1.1 to 1.2 inches of

backfat over the last rib. Each one-tenth inch change in backfat thickness over the last rib

changes the grade by 40 percent of a grade. 
4

(g) The second factor considered in barrow and gilt carcass grading is the degree of muscling. 

The degree of muscling is determined by a subjective evaluation of the thickness of muscling in

relation to skeletal size. Since the total thickness of a carcass is affected by both the amount of fat

and the amount of muscle in relation to skeletal size, the fatness must also be considered when

degree of muscling is evaluated. To best evaluate muscling, primary consideration is given to

those parts least affected by fatness, such as the ham. In evaluating the ham for degree of

muscling, consideration should be given to both the stifle and back views. The size of the lumbar

lean area and the relative width through the back or loin and through the center of the ham are

also good indications of muscling. 

(h) In barrow and gilt carcass grading, three degrees of muscling -- thick (superior), average,

and thin (inferior) -- are considered. In previous standards (33 FR 5081) six degrees of muscling

(very thick, thick, moderately thick, slightly thin, thin, and very thin) were recognized. The

current thick (superior) muscling includes only those carcasses previously classed as very thick. 

Current average muscling includes the previous thick and moderately thick degrees, and the

current thin (inferior) muscling includes the previous slightly thin, thin, and very thin degrees. 

Carcasses with thick muscling and a low degree of fatness will be much thicker through the hams

than through the loins and the loins will appear full and well-rounded. Thick muscled carcasses

with a high degree of fatness will be slightly thicker through the hams than through the loins, will

be nearly flat over the loins, and will have a slight break into the sides. Thick muscled carcasses

will usually have a large lumbar lean area and greater than average depth of chine. Average

muscled carcasses with a low degree of fatness will be thicker through the hams than through the

loins, and the loins will appear slightly full and rounded. Carcasses with average muscling and a

high degree of fatness will have about equal thickness through the hams and loins. Carcasses with

thin muscling and a low degree of fatness usually are slightly thicker through the shoulders and

the center of the hams than through the back and the loins will appear sloping and flat. Thin

muscled carcasses with a high degree of fatness will be wider through the loins than through the

hams and will have a distinct break from over the loins into the sides. Thin muscled carcasses will

usually have a small lumbar lean area and less than average depth of chine. 

(i) Barrow and gilt carcasses with average muscling will be graded according to their backfat

thickness over the last rib. Carcasses with thin muscling will be graded one grade lower than

indicated by the backfat thickness over the last rib. Carcasses with thick muscling will be graded

one grade higher than indicated by their backfat thickness over the last rib except that carcasses

with 1.75 inches or greater backfat thickness over the last rib must remain in the U.S. No. 4

grade. 

(j) The official barrow and gilt carcass grade standards contain a mathematical equation for

calculating the grade and a table for determining a preliminary grade based on the backfat

thickness over the last rib. In determining the final grade all fractions are dropped, the grade is

not rounded to the nearest whole number. Also, the individual grade specifications describe the

various combinations of muscling and backfat thickness over the last rib which qualify for that

grade. 
5

§54.135 Specifications for official United States standards for grades of barrow and gilt

carcasses. 

(a) The grade of a barrow or gilt carcass is determined on the basis of the following equation:

Carcass grade = (4.0 X backfat thickness over the last rib, inches) (1.0 X muscling score). To

apply this equation, muscling should be scored as follows: thin muscling = 1, average muscling =

2, and thick muscling = 3. Carcasses with thin muscling cannot grade U.S. No. 1. The grade may

also be determined by calculating a preliminary grade according to the schedule shown in Table 2,

and adjusting up or down one grade for thick or thin muscling, respectively. 

TABLE 2 -- Preliminary Carcass Grade Based on Backfat Thickness Over the Last Rib

Preliminary Grade Backfat thickness range

U.S. No. 1 ...................................... Less than 1.00 inch.

U.S. No. 2 ...................................... 1.00 to 1.24 inches.

U.S. No. 3 ...................................... 1.25 to 1.49 inches.

U.S. No. 4 ...................................... 1.50 inches and over.1

Carcasses with last rib backfat thickness of 1.75 inches or over cannot be graded U.S. 1

No. 3, even with thick muscling.

(b) The following descriptions provide a guide to the characteristics of barrow and gilt

carcasses in each grade. 

(1) U.S. No. 1. (i) Barrow and gilt carcasses in this grade have an acceptable quality of lean

and belly thickness and a high expected yield (60.4 percent and over) of four lean cuts. U.S. No.

1 barrow and gilt carcasses must have less than average backfat thickness over the last rib with

average muscling, or average backfat thickness over the last rib coupled with thick muscling. 

(ii) Barrow and gilt carcasses with average muscling will be graded U.S. No. 1 if their backfat

thickness over the last rib is less than 1.00 inch. Carcasses with thick muscling will be graded

U.S. No. 1 if their backfat thickness over the last rib is less than 1.25 inches. Carcasses with thin

muscling may not be graded U.S. No. 1. 

(2) U.S. No. 2. (i) Barrow and gilt carcasses in this grade have an acceptable quality of lean

and belly thickness and an average expected yield (57.4 to 60.3 percent) of four lean cuts. 

Carcasses with average backfat thickness over the last rib and average muscling, less than average

backfat thickness over the last rib and thin muscling, or greater than average backfat thickness

over the last rib and thick muscling will qualify for this grade. 

(ii) Barrow and gilt carcasses with average muscling will be graded U.S. No. 2 if their backfat

thickness over the last rib is 1.00 to 1.24 inches. Carcasses with thick muscling will be graded

U.S. No. 2 if their backfat thickness over the last rib is 1.25 to 1.49 inches. Carcasses with thin

muscling must have less than 1.00 inch of backfat thickness over the last rib to be graded U.S.

No. 2. 

(3) U.S. No. 3. (i) Barrow and gilt carcasses in this grade have an acceptable quality of lean

and belly thickness and a slightly low expected yield (54.4 to 57.3 percent) of four lean cuts. 

Carcasses with average muscling and more than average backfat thickness over the last rib, thin
6

muscling and average backfat thickness over the last rib, or thick muscling and much greater than

average backfat thickness over the last rib will qualify for this grade. 

(ii) Barrow and gilt carcasses with average muscling will be graded U.S. No. 3 if their backfat

thickness over the last rib is 1.25 to 1.49 inches. Carcasses with thick muscling will be graded

U.S. No. 3 if their backfat thickness over the last rib is 1.50 to 1.74 inches. Carcasses with 1.75

inches or greater backfat thickness over the last rib cannot grade U.S. No. 3. Carcasses with thin

muscling will be graded U.S. No. 3 if their backfat thickness over the last rib is 1.00 to 1.24

inches. 

(4) U.S. No. 4. (i) Barrow and gilt carcasses in this grade have an acceptable quality of lean

and belly thickness and a low expected yield (less than 54.4 percent) of four lean cuts. Carcasses

in the U.S. No. 4 grade always have more than average backfat thickness over the last rib, and

thick, average, or thin muscling, depending on the degree to which the backfat thickness over the

last rib exceeds the average. 

(ii) Barrow and gilt carcasses with average muscling will be graded U.S. No. 4 if their backfat

thickness over the last rib is 1.50 inches or greater. Carcasses with thick muscling will be graded

U.S. No. 4 with backfat thickness over the last rib of 1.75 inches or greater, and those with thin

muscling will be graded U.S. No. 4 with 1.25 inches or greater backfat thickness over the last rib. 

(5) U.S. Utility. All carcasses with unacceptable quality of lean or belly thickness will be

graded U.S. Utility, regardless of their degree of muscling or backfat thickness over the last rib. 

Also, all carcasses which have soft and/or oily fat will be graded U.S. Utility. 

§54.136 Application of standards for grades of sow carcasses. 

(a) The standards for grades of sow carcasses are based on (1) differences in yields of lean

cuts and of fat cuts and (2) differences in quality of cuts. There are rather uniform differences in

these characteristics from one grade to another. The U.S. No. 1 grade has about the minimum

degree of finish required to produce cuts of acceptable palatability. The four major trimmed lean

cuts -- hams, loins, picnics, and butts -- normally make up more than 48 percent of carcass

weight. The U.S. No. 2 and U.S. No. 3 grades have successively higher degrees of finish

resulting in lower yields of lean cuts and higher yields of fat cuts than U.S. No. 1 grade. Yields of

lean cuts average 45 to 48 percent and under 45 percent of carcass weight, respectively, for U.S.

No. 2 and U.S. No. 3 grades. In addition, the cuts from these grades have more fat remaining

after trimming of external fat than do the cuts from U.S. No. 1 grade carcasses. Medium grade

carcasses are underfinished and exhibit the lack of firmness and indications of little or no marbling

(fat interspersed within the lean) associated with low palatability. Cull grade carcasses are

decidedly underfinished and the pork is soft with very little evidence of marbling and is of low

palatability. 

(b) The standards for grades of sow carcasses apply only to carcasses with the firmness

appropriate to their degree of finish. However, carcasses which are typically soft or oily as a

result of feeds producing soft or oily fat may be graded in accordance with the standards provided

they are identified as soft or oily along with the grade. 

(c) There are differences in the bellies of sow carcasses which are peculiar to the class. 

Increasing numbers of litters farrowed and raised by a sow result in greater development of
7

mammary tissue and increasing roughness of the belly along the teat line with accompanying

seediness. In addition, when pigs were weaned only a short time before the sow was slaughtered

the mammary tissue still contains milk and the bellies are commonly termed “wet.” However, the

smoothness or dryness of bellies has little appreciable effect on the basic grade determining factors

and the standards contain no provision for altering the grade of a sow carcass due to these belly

characteristics. Rather than forming a part of the basis for grade, it is the intent of the standards

that smoothness and dryness of bellies should be a separate consideration used in conjunction with

grade, weight, and other factors in evaluating sow carcasses. 

(d) Average back fat thickness measurements provide a reliable indication of the yields of cuts

and the quality of cuts which determine the grade of sow carcasses. Therefore, indication of a

specific range in back fat thickness for each grade forms a part of the standards for grade. 

Analysis of measurement and cutting data for sow carcasses reveals that yields of cuts are

approximately equal in carcasses which are equal in fat thickness but widely different in weight. 

Thus, to maintain comparable yields in a grade at all weights, back fat thickness requirements for

a grade are the same at all weights. This is in contrast to the standards for barrows and gilts, in

which the fat thickness for a grade increases for heavier or longer carcasses in order to maintain

yields of cuts. With practice in the grading operation, visual estimates of fat thickness may often

replace actual measurements with satisfactory accuracy. The following table of measurements

provides an objective guide in determining the grade of sow carcasses.

Grade Average back fat thickness1

U.S. No. 1 ....................................... 1.5 to 1.9 inches.

U.S. No. 2 ....................................... 1.9 to 2.3 inches.

U.S. No. 3 ....................................... 2.3 or more inches.

Medium .......................................... 1.1 to 1.5 inches.

Cull ............................................... Less than 1.1 inches.

Average of three measurements, skin included, made opposite first and last ribs and the last 1

lumbar vertebrae.

(e) In addition to the measurement guides to grade, the standards also include descriptive

specifications outlining the characteristics of sow carcasses typical of the minimum degree of

finish for each grade. Average back fat thickness is a major factor in grading, but more accurate

appraisal of yields of cuts and quality of cuts is achieved in borderline cases by consideration of

thickness of muscling, conformation of the major cuts, uniformity of fleshing and finish firmness,

and indications of marbling. However, in no case may the final grade of a carcass be more than

one-half the width of a grade different from that indicated by average back fat thickness. 

(f) The standards describe rather typical carcasses of each grade, and no attempt is made to

describe the numerous combinations of characteristics that may qualify a carcass for a particular

grade. 
8

§54.137 Specifications for official United States standards for grades of sow carcasses. 

(a) U.S. No. 1 grade. U.S. No. 1 grade sow carcasses have about the minimum degree of

finish required to produce pork cuts of acceptable palatability. Meatiness and yield of lean cuts

from carcass weight are slightly high. Yield of fat cuts is slightly low. The ratio of total lean and

fat to bone is slightly high. Carcasses with the minimum finish required for U.S. No. 1 grade are

moderately long and slightly wide in relation to weight. The back and loins are moderately full

and thick with a well-rounded appearance. Hams are usually moderately thick and plump and are

slightly full in the lower part toward the hock. Bellies are moderately long, slightly thick, and

moderately uniform in thickness with a slightly thick belly pocket. Shoulders are slightly thick and

full. Carcasses are usually moderately well-balanced and moderately uniform in fleshing and

finish. There are moderate quantities of interior fat in the pelvic area, a slightly thin but

moderately extensive layer of fat lining the inside surface of the ribs, and a slightly small quantity

of feathering, or fat intermingled with the lean between the ribs. The lean is firm. Both exterior

and interior fats are firm, white, and of excellent quality. Carcasses with back fat thickness

qualifying them for the fatter one-half of the U.S. No. 1 grade but with thin muscling in the major

cuts, uneven fleshing and finish, or thick and uneven bellies shall be graded U.S. No. 2. Carcasses

with back fat thickness qualifying them for the thinner one-half of the U.S. No. 1 grade but with

only a moderately thin and incomplete rib lining, a moderately small quantity of feathering, slightly

thin bellies with moderately thin belly pockets, and moderately soft lean and fat shall be graded

Medium. 

(b) U.S. No. 2 grade. U.S. No. 2 grade sow carcasses have a higher degree of finish than the

minimum required to produce pork cuts of acceptable palatability. Meatiness and yield of lean

cuts from carcass weight are slightly low. Yield of fat cuts is slightly high. The ratio of total lean

and fat to bone is moderately high. Carcasses with the minimum finish required for U.S. No. 2

grade are slightly short and moderately wide in relation to weight. The back and loins are full and

thick and are especially full near the edges. Hams are usually thick and plump and are moderately

full in the lower part toward the hock. Bellies are slightly short, moderately thick, and rather

uniform in thickness with a moderately thick belly pocket. Shoulders are moderately thick and

full. Carcasses are usually well-balanced and uniform in fleshing and finish. There are slightly

large quantities of interior fat in the pelvic area, a slightly thick and rather extensive layer of fat

lining the inside surface of the ribs, and moderate feathering. The lean is firm. Both exterior and

interior fats are firm, white, and of excellent quality. Carcasses with back fat thickness qualifying

them for the fatter one-half of the U.S. No. 2 grade but with thin muscling in the major cuts

uneven fleshing and finish, or very thick and uneven bellies shall be graded U.S. No. 3. Carcasses

with back fat thickness qualifying them for the thinner one-half of the U.S. No. 2 grade but with

thick muscling in the major cuts, well-balanced fleshing and uniform finish and slightly thick

bellies shall be graded U.S. No. 1. 

(c) U.S. No. 3 grade. U.S. No. 3 grade sow carcasses have a decidedly higher degree of finish

than the minimum required to produce pork cuts of acceptable palatability. Meatiness and yield of

lean cuts from carcass weight are low. Yield of fat cuts is high. The ratio of total lean and fat to

bone is high. Carcasses with the minimum finish required for U.S. No. 3 grade are short and wide

in relation to weight. The back and loins are very full and thick and are decidedly full at the
9

edges. Hams are usually very thick and plump and are full in the lower part toward the hock due

to a thick fat covering. Bellies are short and thick and uniform in thickness with a thick belly

pocket. Shoulders are thick and full. Carcasses are usually well-balanced and uniform in fleshing

and finish. There are large quantities of interior fat in the pelvic area, a moderately thick and

extensive layer of fat lining the inside surface of the ribs, and slightly abundant feathering. The

lean is firm. Both exterior and interior fats are firm, white, and of excellent quality. Carcasses

with back fat thickness indicative of nearly minimum finish for the U.S. No. 3 grade but with thick

muscling in the major cuts, well-balanced fleshing and uniform finish, and moderately thick bellies

shall be graded U.S. No. 2. 

(d) Medium grade. Medium grade sow carcasses have a lower degree of finish than the

minimum required to produce pork cuts of acceptable palatability. Yield of lean cuts from carcass

weight is moderately high. Yield of fat cuts is moderately low. The ratio of total lean and fat to

bone is moderately low. Carcasses with the minimum finish required for Medium grade are long

and rather narrow in relation to weight. The back and loins are rather thin, lack fullness, and

slope away from the center. Hams are usually slightly thin, lack plumpness, and taper toward the

hock. Bellies are long and moderately thin and are somewhat uneven in thickness with a thin belly

pocket. Shoulders are moderately thin and flat. Carcasses tend to be uneven and lack uniformity

of fleshing and finish. There are slightly small quantities of interior fat in the pelvic area, a thin

and incomplete layer of fat lining the inside surface of the ribs, and only a small quantity of

feathering. The lean is moderately soft with little evidence of marbling. Both exterior and interior

fats are moderately soft, white to creamy white, and of moderately low quality. Carcasses with

back fat thickness qualifying them for the fatter one-half of the Medium grade that are firm and

have slightly thick bellies and belly pockets, a slightly thin but moderately extensive rib lining, and

a slightly small quantity of feathering shall be graded U.S. No. 1. Carcasses with back fat

thickness qualifying them for the thinner one-half of the Medium grade but with little or no rib

lining and feathering, thin bellies and very thin belly pockets, and soft lean and fat shall be graded

Cull. 

(e) Cull grade. Cull grade sow carcasses have a decidedly lower degree of finish than the

minimum required to produce pork cuts of acceptable palatability. Yield of lean cuts from carcass

weight is high. Yield of fat cuts is low. The ratio of total lean and fat to bone is low. Carcasses

with the degree of finish typical of the Cull grade are long and narrow in relation to weight. The

back and loins are thin and decidedly lacking in fullness with a definite slope toward the sides. 

Hams are usually thin and flat and taper toward the hock. Bellies are very long and thin and are

uneven in thickness with a very thin belly pocket. Shoulders are thin and flat. Carcasses tend to

be uneven and lack uniformity of fleshing and finish. There are only small quantities of interior fat

in the pelvic area, little or no fat lining the inside surface of the ribs, and scant feathering. The

lean is soft and watery with very little evidence of marbling. Both exterior and interior fats are

soft, creamy white to white, and of low quality. Carcasses with back fat thickness indicative of

nearly maximum finish for the Cull grade that are only moderately soft and have moderately thin

bellies and belly pockets, a thin and incomplete rib lining, and a small quantity of feathering shall

be graded Medium.