United States

Department of

Agriculture

Agricultural 

Marketing

Service

Livestock

and Seed

Division

United States Standards

for Grades of

Slaughter Lambs,

Yearlings, and Sheep

Effective date July 6, 1992
1

United States Standards for Grades of Slaughter Lambs,

Yearlings, and Sheep

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

Lambs, Yearlings, and Sheep 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 July 6, 1992.

Development of the Standards

Tentative United States Standards for the Market Classes and Grades of Slaughter Lambs and

Sheep were prepared in 1917 to provide a basis on which the Federal Market News Service issue

market quotations on these animals, according to a uniform classification. Preliminary grade

descriptions were mimeographed and distributed. Suggestions for their improvement were

solicited and received from producers, animal husbandmen, market agencies, and slaughterers.

These suggestions were used in further perfecting the standards.

Late in 1926 and early 1927, public hearings were held in Portland (OR), San Francisco, Salt

Lake City, Denver, Fort Worth, Kansas City, Omaha, St. Paul, Chicago, Boston, New York, and

Philadelphia. Invitations to attend these hearings were sent to livestock producers, slaughterers,

wholesale and retail dealers, agricultural college workers, and others interested in the livestock

and meat industries. The sentiment developed in these hearings was decidedly in factor of the

standardized grades for lambs, yearlings, and sheep, as presented. Criticisms and suggestions

brought out in these hearings were given careful consideration in later revisions of the tentative

standards which were printed in March 1936, circular No. 383. The circular was slightly revised

in July 1940.

The tentative standards for grades of slaughter sheep were revised and promulgated by the

Secretary of Agriculture as the official United States standards for grades of slaughter lambs,

yearlings, and sheep, effective April 30, 1951. These standards were issued as Service and

Regulatory Announcements No. 168. The revisions in the tentative standards, at the time of their 

promulgation as official standards, combined the Prime and Choice grades and designated them as

Prime. The Good grade was renamed as Choice, which also became the highest grade for which

slaughter sheep older than yearlings are eligible. The top two-thirds of the Medium grade was

renamed Good; the lower one-third of the Medium grade was combined with the upper two-thirds

of the Common grade and designated as Utility; and the lower one-third of the Common grade

was combined with the Cull grade and designated as Cull. The revisions also provided for

indicating in the standards the minimum requirements for each grade and specified the grade

requirements at varying degrees of maturity.

In February 1957, revisions were made in the slaughter sheep standards to coordinate them

with changes made in the carcass lamb and sheep standards. The quality requirements for the
2

Prime and Choice grades were reduced for the more mature lambs. In the Good grade, the

quality requirements were increased slightly, particularly for very young lambs. Another major

change made in the standards was to permit sheep and lambs with quality indications sufficient for

only the upper one-third of the Good grade to be graded Choice provided they have at least midpoint Choice conformation.

Following another change in carcasses standards, a further revision was made in June 1960. 

This major decision lowered both the quality and conformation requirements for the Prime and

Choice grades. The conformation requirements in the Prime and Choice grades were lowered

about one-half grade. The quality requirements for the very young lambs in both the Prime and

Choice grades were reduced about one-half grade; in the more mature lambs, the Prime grade

requirements were lowered about one full grade and in the Choice grade about two-thirds of a

grade. Other changes limited the extent that superior quality may compensate for deficient

conformation.

In March 1969, the standards were revised by adopting yield grade standards for optional use

with the quality grades. The yield grades standards were based on the results of studies

conducted by the Department, several land-grant universities, and the industry on lamb carcass

cutability. Based on that research, and the request of the National Wood Growers Association,

the Department proposed in the yield grades on August 16, 1968, and they became effective on

March 1, 1969. Changes also were made in the “Application of Standards” section as needed to

implement the yield grades and to clarify some other points. No changes were made in the quality

grade standards.

In November 1984, changes were once again made in the slaughter lambs, yearlings, and sheep

standards to coordinate them with previous changes in he carcass grade standards. Several of

those changes did not necessitate corresponding changes in the slaughter standards. However,

changes were necessary in the rate of quality and conformation compensations, muscling

descriptions were added to the conformation descriptions for each grade, and the Cull grade was

dropped for lambs and yearlings. These changes also necessitated splitting the yearlings and

sheep into two separate specifications since the Cull grade was no longer applicable to the

yearlings.

When the carcass standards were revised in July 1992, the standards for slaughter lambs,

yearlings, and sheep were once again revised to reflect those changes. The changes made were

“coupling” of the quality and yield grades to require that carcasses be identified for both quality

and yield when officially graded, and to require removal of most of the kidney and pelvic fat prior

to grading. In addition, leg conformation score was eliminated as a yield grade factor and the fat

thickness range in each yield grade was shifted and narrowed. The slaughter standards were

revised to reflect those changes in the carcass standards. These changes were initiated in response

to requests from producers--represented by the American Sheep Industry (ASI) Association--to

provide an improved communication tool to efficiently reflect consumers’ preferences for lean

meat products back to producers. The changes officially proposed on November 20, 1991, and

were overwhelmingly supported by all industry segments except lamb feeders and lamb

slaughterers and processors. Those two segments of the industry were split on the changes. The

revised standards were effective on July 6, 1992.
3

§53.130 Market sheep.

The official standards for market sheep, developed by the United States Department of

Agriculture, provide for segregation according to (a) use as slaughter animals or feeders; (b) class

or sex conditions; (c) age group; and (d) grade, which is determined by the apparent relative

excellence and desirability of the individual animal for a particular use. 

§53.131 Slaughter classes and market groups. 

The classes of slaughter sheep are ram, ewe, and wether; the age groups are lambs, yearlings,

and sheep. Definitions of the respective classes and age groups are as follows: 

(a) Ram. A ram is an uncastrated male ovine. 

(b) Ewe. A ewe is a female ovine. 

(c) Wether. A male ovine castrated when young and prior to developing the secondary

physical characteristics of a ram. 

(d) Lamb. A lamb is an immature ovine, usually under 14 months of age, that has not cut its

first pair of permanent incisor teeth. 

(e) Yearling. A yearling is an ovine usually between one and two years of age, that has cut its

first pair of permanent incisor teeth but has not cut the second pair. 

(f) Sheep. A sheep is an ovine, usually over 24 months of age, that has cut its second pair of

permanent incisor teeth. 

§53.132 Application of standards. 

(a) Grade factors. Grades of slaughter ovines are intended to be directly related to the grades

of the carcasses they produce. To accomplish this, these slaughter ovine grade standards are

based on factors which are directly related to the quality grades and yield grades of ovine

carcasses. The standards are written so that the quality and yield grade standards are contained in

separate sections. The quality grade standards are further divided into three sections applicable to

slaughter lambs, slaughter yearlings, and slaughter sheep. There are four quality grades within

each class -- Prime, Choice, Good, and Utility for lambs and yearlings; and Choice, Good, Utility,

and Cull for sheep. Also, there are five yield grades applicable to all classes of slaughter ovine,

denoted by numbers 1 through 5, with Yield Grade 1 representing the highest degree of cutability. 

When officially graded slaughter ovines are identified for both quality and yield grades. 

(b) General principles. (1) The determination of the carcass grade that the slaughter animal

will produce requires the exercise of well-regulated judgment. Each animal presents a different

combination of the grade-determining factors. Animals frequently have characteristics associated

with two or more grades. Therefore, a composite evaluation of all inherent physical

characteristics is essential for accuracy in determining grade. 

(2) The accurate determination of the grade of a slaughter ovine requires handling in addition

to visual observation. The length and density of the fleece vary greatly with individuals, and the

thickness and firmness of the flesh covering of wooled ovine can only be roughly estimated

without handling. The technique used in handling usually varies with the degree of precision in
4

mind as well as the experience of the grader. Experienced graders may find one quick handling

satisfactory. This usually consists of placing the one open hand over the back and ribs in

simultaneous motion. The thumb extends just over the backbone, while the fingers, which are

held close together, cover the rib section, and pressure is applied very lightly with a slight lateral

and forward and backward motion. The generally accepted technique of handling ovines where

time permits, and especially when noting slight differences between individuals, is to handle

forward from the dock to neck with the open hand, fingers together, laid flat and with a slight

lateral motion. Both hands may be used, one on each side, in a similar manner to determine the

fleshing over the shoulders, ribs, and hips. Regardless of the method, considerable experience is

necessary in handling ovine to accurately determine the grade. 

(c) Quality grades. (1) The quality grade of a slaughter ovine is determined by a composite

evaluation of two general considerations which influence carcass excellence: conformation and

quality -- fatness, maturity, and other indicators of differences in palatability of the lean flesh. 

(2) Conformation refers to the general body proportions of the animal and to the ratio of meat

to bone. Although primarily determined by the inherent muscular and skeletal systems, it is also

influenced by the degree of fatness. However, external fat in excess of that normally left on retail

cuts is not considered in evaluating conformation. The conformation descriptions included in

each of the grade specifications refer to the thickness of muscling and to an overall degree of

thickness and fullness of the animal. Slaughter ovines which meet the requirements for thickness

of muscling specified for a grade will be considered to have conformation adequate for that grade

despite the fact that, because of a lack of fatness, they may not have the overall degree of

thickness and fullness described. Conformation is evaluated by averaging the conformation of the

various component parts, giving special consideration to those parts of the body producing the

more desirable cuts of meat -- loin, hotel rack, and leg. 

(3) In grading slaughter ovines, quality of the lean must be evaluated indirectly by considering

the quantity, distribution, and type of fat or finish in relation to the maturity of the animal being

graded. Finish is evaluated by noting variations in the fullness and apparent thickness of the fat

covering over the back, loin, ribs, and legs. A high degree of desirable finish is evidenced by a

firm, smooth layer of fat which is uniformly distributed over the body. To be eligible for the

Prime or Choice grades, a slaughter ovine must have at least a very thin covering of external fat

over the top of the shoulders and the outside of the legs, and the back must have at least a thin

(approximately 0.07 inch) covering of fat. 

(4) Although the market designation of slaughter ovines is usually made by classes, the quality

standards are intended to apply to all classes without regard to sex condition. However, male

animals which have thick, heavy necks and shoulders typical of uncastrated males are discounted

in grade in proportion to the extent to which these characteristics are developed. Such discounts

may vary from less than one-half a grade in young lambs in which such characteristics are barely

noticeable, to as much as two full grades in mature rams in which such characteristics are very

pronounced. 

(d) Yield grades. (1) The yield grades for slaughter ovines (like the grades for ovine carcasses)

are based on the thickness of fat over the ribeye. As the amount of external fat increases, the

percent of retail cuts decreases and the numerical yield grade increases. The adjusted fat

thickness range for each yield grade is as follows: Yield Grade 1 -- 0.00 to 0.15 inch; Yield Grade
5

2 -- 0.16 to 0.25 inch; Yield Grade 3 -- 0.26 to 0.35 inch; Yield Grade 4 -- 0.36 to 0.45 inch; and

Yield Grade 5 -- 0.46 inch and greater. On slaughter ovines which do not have a normal

distribution of external fat, the fat thickness estimate over the ribeye may be adjusted, as

necessary, to reflect unusual amounts of fat on other parts of the animal. In fact an evaluation of

overall fatness, or direct estimation of yield grade may be preferred by experienced evaluators. 

(2) The overall fatness of an animal can be determined best by giving particular attention to

those parts on which fat is deposited at a faster-than-average rate. These include the back, loin,

rump, flank, breast, and cod or udder. As ovines increase in fatness these parts become

progressively fuller, thicker, and more distended in relation to the thickness and fullness of the

other parts, particularly the legs. However, since an animal's thickness of muscling also affects

the development of its various parts, this also needs to be considered when evaluating the degree

of fatness. In thinly muscled ovines with a low degree of finish, the width of the back usually will

be greater than the width through the center of the legs. Conversely, in thickly muscled ovines

with a low degree of finish, the thickness through the legs will be greater than through the back

and the back will be full and rounded. At an intermediate degree of fatness, ovine which are thinly

muscled will be considerably wider through the back than through the leg and will be nearly flat

across the back. Thickly muscled ovines that have an intermediate degree of fatness will be about

the same width through the legs as through the back and the back will appear only slightly

rounded. Very fat ovines will be wider through the back than through the legs, but this difference

will be greater in thinly muscled ovines than in those that are thickly muscled. As ovines increase

in fatness, they also become deeper bodied because of large deposits of fat in the flanks and breast

and along the underline. 

(e) Other considerations. (1) Other factors, such as sex, heredity, and management also may

affect the development of grade-determining characteristics in slaughter ovines. Although these

factors do not lend themselves to descriptions in the standards, the use of factual information of

this nature is justified in determining the grade of slaughter ovines. The ability to make proper

allowances for the effects of genetic and management factors on the appearance of

grade-determining characteristics must be developed through experience. 

(2) Slaughter ovines qualifying for any particular grade may vary with respect to the relative

development of their individual grade factors. In fact, some will qualify for a particular grade

although they have some characteristics more typical of ovine in another grade. Because it is

impractical to describe the nearly infinite number of such recognizable combinations of

characteristics, the standards describe only ovines which have a relatively similar development of

the various quality and yield grade-determining factors and which are near the lower limits of

quality or yield for the grade. However, examples of the extent to which superiority in

quality-indicating characteristics may compensate for deficiencies in conformation, and vice versa,

are indicated for each quality grade. In the slaughter lamb quality grade standards, the

requirements are given for two maturity groups. In the yield grade standards, fat thickness

descriptions are given for slaughter ovines which are near the maximum fatness for each of the

first four yield grades. 
6

§53.133 Specifications for official U.S. standards for grades of slaughter lambs (quality). 

(a) Prime. (1) Slaughter lambs having minimum conformation requirements for the Prime

grade tend to be thickly muscled throughout, and they are moderately wide and thick in relation to

their length and height. The are moderately wide over the back, loin, and rump. Shoulders and

hips are usually moderately smooth. The twist is moderately deep and full, and the legs are

moderately large and plump. They generally present a well-rounded appearance due to a slight

fullness or plumpness over the crops, loins, and rump. Relatively young lambs, under seven

months of age, tend to have a moderately thin fat covering over the back, ribs, loins, and rump. 

In handling, the backbone and ribs are readily discernible. Older, more mature lambs have a

slightly thin fat covering over the back, ribs, loin, and rump. In handling, the backbone and ribs

are slightly discernible. Prime grade lambs exhibit evidences of rather high quality. The bones

tend to be proportionately small, the joints tend to be smooth, and the body tends to be smooth

and symmetrical. 

(2) To qualify for the Prime grade, a lamb must possess the minimum qualifications for finish

regardless of the extent that its conformation may exceed the minimum requirements for Prime. 

However, a development of finish which is superior to that specified as minimum for the Prime

grade may compensate, on an equal basis, for a development of conformation which is inferior to

that specified for Prime as indicated in the following example: A lamb which has evidences of

finish equivalent to the midpoint of the Prime grade may have conformation equivalent to the

midpoint of the Choice grade and remain eligible for Prime. However, in no instance may a lamb

be graded Prime which has a development of conformation inferior to that specified as minimum

for the Choice grade. 

(b) Choice. (1) Slaughter lambs having minimum conformation requirements for the Choice

grade are slightly thick muscled throughout, and they tend to be slightly wide and thick in relation

to their length and height. They tend to be slightly wide over the back, loin, and rump. The

shoulders and hips are usually slightly smooth but may exhibit a slight tendency toward

prominence. The twist tends to be slightly deep and full, and the legs tend to be slightly thick and

plump. Relatively young lambs, under seven months of age, have a thin fat covering over the

back, ribs, loin, and rump. In handling, the backbone and ribs are moderately prominent. Older,

mature lambs have a moderately thin fat covering over the back, ribs, loin, and rump. In handling,

the backbone and ribs are slightly prominent. Choice grade lambs usually present a moderately

refined appearance. 

(2) A development of quality which is superior to that specified as minimum for the Choice

grade may compensate, on a equal basis, for a development of conformation which is inferior to

that specified as minimum for Choice as indicated in the following example: A lamb which has

evidences of quality equivalent to the midpoint of the Choice grade may have conformation

equivalent to the midpoint of the Good grade and remain eligible for Choice. However, in no

instance may a lamb be graded Choice which has a development of conformation inferior to that

specified as minimum for the Good grade. Also, a lamb which has conformation at least one-third

grade superior to that specified as minimum for the Choice grade may qualify for Choice with a

development of quality equivalent to the lower limit of the upper one-third of the Good grade. 

Compensation of superior conformation for inferior quality is limited to one-third grade of
7

deficient quality. 

(c) Good. (1) Slaughter lambs having minimum conformation requirements for the Good grade

are slightly thin muscled throughout, and are moderately narrow in relation to their length and

height and are slightly narrow over the back, loin, and rump. Hips and shoulders are moderately

prominent. The twist is slightly shallow and the legs are slightly small and thin. Relatively young

lambs, under seven months of age, have slightly more than a very thin, uneven fat covering over

the back, loin, and upper ribs. In handling, the shoulders, backbone, hips, and ribs are prominent. 

Older, more mature lambs have slightly more than a thin fat covering over the back, ribs, and loin. 

In handling, the bones of the shoulders, backbone, hips, and ribs are rather prominent. Good

grade lambs may present evidences of slightly low quality. The bones and joints are usually

moderately large, and the body is somewhat lacking in symmetry and smoothness. 

(2) A development of quality which is superior to that specified as minimum for the Good

grade may compensate, on an equal basis, for a development of conformation which is inferior to

that specified as minimum for Good as indicated in the following example: A lamb which has

evidences of quality at least one-third grade superior to that specified as minimum for the Good

grade may have conformation equivalent to the minimum for the upper one-third of the Utility

grade and remain eligible for Good. However, in no instance may a lamb be graded Good which

has a development of conformation inferior to the minimum for the upper one-third of the Utility

grade. Also, a lamb which has conformation at least one-third grade superior to that specified as

minimum for the Good grade may qualify for Good with a development of quality equivalent to

the lower limit of the upper one-third of the Utility grade. Compensation of superior

conformation for inferior quality is also limited to one-third grade of deficient quality. 

(d) Utility. The Utility grade consists of those lambs whose characteristics are inferior to those

specified as minimum for the Good grade. 

§53.134 Specifications for official U.S. standards for grades of slaughter yearlings (quality). 

(a) Prime. (1) Slaughter yearlings having minimum conformation requirements for the Prime

grade tend to be thickly muscled throughout, and are moderately wide and thick in relation to

their length and height, and they are moderately wide over the back, loin, and rump. Shoulders

and hips are usually moderately smooth. The twist is moderately deep and full, and the legs are

moderately large and plump. There is a rather distinct fullness or plumpness evident over the

crops, loins, and rump which contributes to a well-rounded appearance. There is a slightly thick

fat covering over the back, ribs, loin, and rump. In handling, the backbone and ribs are hardly

discernible. Prime grade slaughter yearlings exhibit evidences of rather high quality. The bones

tend to be proportionately small, the joints tend to be smooth, and the body tends to be smooth

and symmetrical. 

(2) Regardless of the extent to which its conformation may exceed the minimum requirements

for Prime, a yearling must have minimum Prime quality to be eligible for the Prime grade. 

However, a development of quality which is superior to that specified as minimum for the Prime

grade may compensate, on an equal basis, for a development of conformation which is inferior to

that specified as minimum for Prime as indicated in the following example: A yearling which has

evidences of quality equivalent to the midpoint of the Prime grade may have conformation
8

equivalent to the midpoint of the Choice grade and remain eligible for Prime. However, in no

instance may a yearling be graded Prime which has a development of conformation inferior to that

specified as minimum for the Choice grade. 

(b) Choice. (1) Slaughter yearlings having minimum conformation requirements for the Choice

grade are slightly thick muscled throughout, and they tend to be slightly wide and thick in relation

to their length and height, and they tend to be slightly wide over the back, loin, and rump. The

shoulders and hips are usually slightly smooth but may show a slight tendency toward

prominence. The twist tends to be slightly deep and full, and the legs tend to be slightly thick and

plump. They have a slightly thin fat covering over the back, ribs, loin, and rump. In handling, the

backbone and ribs are readily discernible. Choice grade slaughter yearlings usually present a

moderately refined appearance. 

(2) A development of quality which is superior to that specified as minimum for the Choice

grade may compensate, on an equal basis, for a development of conformation which is inferior to

that specified as minimum for Choice as indicated in the following example: A yearling which has

evidences of quality equivalent to the midpoint of the Choice grade may have conformation

equivalent to the midpoint of the Good grade and remain eligible for Choice. However, in no

instance may a yearling be graded Choice which has a development of conformation inferior to

that specified as minimum for the Good grade. Also, a yearling which has a development of

conformation at least one-third grade superior to that specified as minimum for the Choice grade

may qualify for Choice with a development of quality equivalent to the lower limit of the upper

one-third of the Good grade. Compensation of superior conformation for inferior quality is

limited to one-third grade of deficient quality. 

(c) Good. (1) Slaughter yearlings having minimum conformation requirements for the Good

grade are slightly thin muscled throughout, and are moderately narrow in relation to their length

and height, and are slightly narrow over the back, loin, and rump. Hips and shoulders are

moderately prominent. The twist is slightly shallow, and the legs are slightly small and thin. They

have slightly more than a moderately thin fat covering over the back, loin, and upper ribs. In

handling, the shoulders, backbone, hips, and ribs are rather prominent. Good grade yearlings may

present evidences of slightly low quality. The body is somewhat lacking in symmetry and

smoothness. 

(2) A development of quality which is superior to that specified as minimum for the Good

grade may compensate, on an equal basis, for a development of conformation which is inferior to

that specified as minimum for Good as indicated in the following example: A yearling which has

evidences of quality at least one-third grade superior to that specified as minimum for the Good

grade may have conformation equivalent to the minimum for the upper one-third of the Utility

grade and remain eligible for Good. However, in no instance may a yearling be graded Good

which has a development of conformation inferior to the minimum for the upper one-third of the

Utility grade. Also, a yearling which has conformation at least one-third grade superior to that

specified as minimum for the Good grade may qualify for Good with a development of quality

equivalent to the lower limit of the upper one-third of the Utility grade. Compensation of

superior conformation for inferior quality is also limited to one-third grade of deficient quality. 

(d) Utility. The Utility grade includes those yearlings whose characteristics are inferior to

those specified as minimum for the Good grade. 
9

§53.135 Specifications for official U.S. standards for grades of slaughter sheep (quality).

(a) Choice. (1) Slaughter sheep having minimum conformation requirements for the Choice

grade are slightly thick muscled throughout, and they tend to be slightly wide and thick in relation

to their length and height, and they tend to be slightly wide over the back, loin, and rump. The

shoulders and hips are usually slightly smooth but may show a slight tendency toward

prominence. The twist tends to be slightly deep and full, and the legs tend to be slightly thick and

plump. They have a slightly thick fat covering over the back, ribs, loin, and rump. In handling,

the backbone and ribs are slightly discernible. Choice grade slaughter sheep usually present a

moderately refined appearance. 

(2) A development of quality which is superior to that specified as minimum for the Choice

grade may compensate, on an equal basis, for a development of conformation which is inferior to

that specified as minimum for Choice as indicated in the following example: A sheep which has

evidences of quality equivalent to the midpoint of the Choice grade may have conformation

equivalent to the midpoint of the Good grade and remain eligible for Choice. However, in no

instance may a sheep be graded Choice which has a development of conformation inferior to that

specified as minimum for the Good grade. Also, a sheep which has conformation at least

one-third grade superior to that specified as minimum for the Choice grade may qualify for Choice

with a development of quality equivalent to the lower limit of the upper one-third of the Good

grade. Compensation of superior conformation for inferior quality is limited to one-third grade of

deficient quality. 

(b) Good. (1) Slaughter sheep having minimum conformation requirements for the Good grade

are slightly thin muscled throughout, and are moderately narrow in relation to their length and

height, and they are slightly narrow over the back, loin, and rump. Hips and shoulders are

moderately prominent. The twist is slightly shallow, and the legs are slightly small and thin. They

have a slightly thin fat covering over the back, ribs, and loin. In handling, the bones of the

shoulders, backbone, hips, and ribs are slightly prominent. Good grade sheep may present

evidences of slightly low quality. The body is somewhat lacking in symmetry and smoothness. 

(2) A development of quality which is superior to that specified as minimum for the Good

grade may compensate, on an equal basis, for a development of conformation which is inferior to

that specified as minimum for Good as indicated in the following example: A sheep which has

evidences of quality equivalent to the midpoint of the Good grade may have conformation

equivalent to the midpoint of the Utility grade and remain eligible for Good. However, in no

instance may a sheep be graded Good which has a development of conformation inferior to that

specified as minimum for the Utility grade. Also, a sheep which has conformation at least

one-third grade superior to that specified as minimum for the Good grade may qualify for Good

with a development of quality equivalent to the lower limit of the upper one-third of the Utility

grade. Compensation of superior conformation for inferior quality is limited to one-third grade of

deficient quality. 

(c) Utility. (1) Slaughter sheep having minimum conformation requirements for the Utility

grade are thinly muscled throughout, and are very angular and very narrow in relation to their

length and height, and they are very thin fleshed, very narrow over the back, loin, and rump, and

very shallow in the twist. The hips are very prominent, and the shoulders are usually open, rough,
10

and prominent. The legs are very small and thin and present a slightly concave appearance. 

Utility grade slaughter sheep show no visible evidences of fat covering. In handling, the bones of

the shoulders, backbone, hips, and ribs are so thinly covered that they are very prominent. Utility

grade slaughter sheep are of rather low quality. The bones and joints are proportionately large,

and the body is very rough and unsymmetrical. 

(2) A development of quality which is superior to that specified as minimum for the Utility

grade may compensate, on an equal basis, for a development of conformation which is inferior to

that specified as minimum for Utility as indicated in the following example: A sheep which has

evidences of quality at least one-third grade superior to that specified as minimum for the Utility

grade may have conformation equivalent to the minimum for the upper one-third of the Cull grade

and remain eligible for Utility. However, in no instance may a sheep be graded Utility which has a

development of conformation inferior to the minimum for the upper one-third of the Cull grade. 

Also, a sheep which has conformation at least one-third grade superior to that specified as

minimum for the Utility grade may qualify for Utility with a development of quality equivalent to

the lower limit of the upper one-third of the Cull grade. Compensation of superior conformation

for inferior quality is also limited to one-third grade of deficient quality. 

(d) Cull. (1) The Cull grade includes those slaughter sheep whose characteristics are inferior

to those specified as minimum for the Utility grade. 

§53.136 Specifications for official U.S. standards for grades of slaughter lambs, yearlings,

and sheep (yield). 

(a) Yield Grade 1. Yield Grade 1 slaughter lambs, yearlings, and sheep produce carcasses

which have very high yields of boneless retail cuts. Ovines with characteristics qualifying them for

the lower limits of Yield Grade 1 (near the borderline between Yield Grade 1 and Yield Grade 2)

will have only a slightly thin covering of external fat over the back, loin, and ribs, and a slightly

thick covering of fat over the rump. They are slightly shallow through the flanks and the brisket

and cod or udder have some evidence of fullness. In handling, the backbone, ribs, and ends of

bones at the loin edge are slightly prominent. A carcass produced from slaughter ovines of this

description might have 0.15 inch of fat over the ribeye. 

(b) Yield Grade 2. Yield Grade 2 slaughter lambs, yearlings, and sheep produce carcasses with

high yields of boneless retail cuts. Ovines with characteristics qualifying them for the lower limits

of Yield Grade 2 (near the borderline between Yield Grade 2 and Yield Grade 3) will have a

slightly thick layer of external fat over the back, loin and ribs, and a thick covering of fat over the

rump. They tend to be slightly deep and full through the flanks and the brisket and cod or udder

are moderately full. In handling, the backbone, ribs, and ends of bones at the loin edge are readily

discernible. A carcass produced from slaughter ovines of this description might have 0.25 inch of

fat over the ribeye. 

(c) Yield Grade 3. Yield Grade 3 slaughter lambs, yearlings, and sheep produce carcasses with

intermediate yields of boneless retail cuts. Ovines with characteristics qualifying them for the

lower limits of Yield Grade 3 (near the borderline between Yield Grade 3 and Yield Grade 4) will

have a thick covering of fat over the back and loin and a very thick covering of fat over the rump

and down over the ribs. The flanks are deep and full and the brisket and cod or udder are full. In
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handling, the backbone, ribs, and ends of bones at the loin edge are difficult to distinguish. A

carcass produced from slaughter ovines of this description might have 0.35 inch of fat over the

ribeye. 

(d) Yield Grade 4. Yield Grade 4 slaughter lambs, yearlings, and sheep produce carcasses with

moderately low yields of boneless retail cuts. Ovines with characteristics qualifying them for the

lower limits of Yield Grade 4 (near the borderline between Yield Grade 4 and Yield Grade 5) will

have a very thick covering of fat over the back and loin, and an extremely thick covering of fat

over the rump and down over the ribs. The flanks are moderately deep and full and the brisket

and cod or udder are full. In handling, the backbone, ribs, and ends of bones at the loin edge are

not discernible. A carcass produced from slaughter ovines of this description might have 0.45

inch of fat over the ribeye. 

(e) Yield Grade 5. Yield Grade 5 slaughter lambs, yearlings, and sheep produce carcasses with

low yields of boneless retail cuts. Ovines of this grade consist of those not meeting the minimum

requirements of Yield Grade 4 because of more fat.