United States

Department of

Agriculture

Agricultural 

Marketing

Service

Livestock

and Seed

Division

United States Standards

for Grades of

Feeder Pigs

Effective date April 1, 1969
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United States Standards for Grades of Feeder Pigs

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

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

April 1, 1969.

Development of the Standards

In 1940, tentative standards for grades of feeder pigs were developed and published by the

Department of Agriculture in Circular No. 569, “Market Classes and Grades of Swine.”

The tentative standards served as the basis for Federal and Federal-State livestock and market

news reports on feeder pigs.

Official standards for grades of feeder pigs were proposed by the United States Department of

Agriculture in 1965. Slight revisions were made in the proposed standards before they were

adopted as the Official United States Standards for Grades of Feeder Pigs, effective January 1,

1966.

On April 1, 1969, the official standards were revised to coordinate them with the pork

carcasses and slaughter swine standards that were revised in 1968. In this revision a new No. 1

grade was established to identify the superior feeder pigs then being produced. The former No. 1,

No. 2, No. 3 grades were renamed No. 2, No. 3, and No. 4, respectively. The Medium grade was

renamed U.S. Utility, and the application of standards section was revised to more clearly define

the grade-determining factors and clarify their use in determining the grades.

§53.150 Swine.

 

The official standards for swine developed by the U.S. Department of Agriculture provide for

segregation first according to intended use -- slaughter or feeder -- then as to class, as determined

by sex condition, and then as to grade, which is determined by the apparent relative excellence

and desirability of the animal for a particular use. Differentiation between slaughter and feeder

swine is based solely on their intended use rather than on specific identifiable characteristics of the

swine. Slaughter swine are those which are intended for slaughter immediately or in the near

future. Feeder swine are those which are intended for slaughter after a period of feeding. 

§53.151 Slaughter and feeder swine classes.

 

There are five classes of slaughter and feeder swine. Definitions of the respective classes are

as follows: 
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(a) Barrow. A barrow is a male swine castrated when young and before development of the

secondary physical characteristics of a boar. 

(b) Gilt. A gilt is a young female swine that has not produced young and has not reached an

advanced stage of pregnancy. 

(c) Sow. A sow is a mature female swine that usually shows evidence of having reproduced or

having reached an advanced stage of pregnancy. 

(d) Boar. A boar is an uncastrated male swine. 

(e) Stag. A stag is a male swine castrated after development or beginning of development of

the secondary physical characteristics of a boar. Typical stags are somewhat coarse and lack

balance -- the head and shoulders are more fully developed than the hindquarter parts, bones and

joints are large, the skin is thick and rough, and the hair is coarse. 

§53.158 Application of standards for grades of feeder pigs. 

(a) The grade of a feeder pig is determined by evaluating two general value-determining

characteristics -- its logical slaughter potential and its thriftiness. 

(b) The logical slaughter potential of a thrifty feeder pig is its expected slaughter grade at a

market weight of 220 pounds after a normal feeding period. In these feeder pig standards, logical

slaughter potential is determined by a composite appraisal of the development of the muscular

system and the skeletal system. Both of these factors have an important effect on the

development of lean and fat as the animal grows and fattens, and therefore, on the expected

slaughter and carcass grade. 

(c) Thriftiness in a feeder pig is its apparent ability to gain weight rapidly and efficiently. Size

for age, health, and other general indications of thriftiness are considered in appraising the

thriftiness of feeder pigs. 

(d) The standards provide for six grades of feeder pigs -- U.S. No. 1, U.S. No. 2, U.S. No. 3,

U.S. No. 4, U.S. Utility, and U.S. Cull. Except for the U.S. Cull grade, these names correspond

to the five grade names for slaughter swine and pork carcasses. The U.S. No. 1, U.S. No. 2, U.S.

No. 3, and U.S. No. 4 grades include all pigs which are thrifty. Differentiation between the U.S.

No. 1, U.S. No. 2, U.S. No. 3, and U.S. No. 4 grades is based entirely on differences in logical

slaughter potential. Feeder pigs in the U.S. No. 1 grade have sufficient muscling and frame to

reach a market weight of 220 pounds with a minimum degree of finish. Feeder pigs in the U.S.

No. 2, U.S. No. 3, and U.S. No. 4 grades usually have progressively less muscling and less frame

and are expected to have progressively more finish when marketed at 220 pounds. The U.S.

Utility and U.S. Cull grades include only pigs which lack thriftiness. Differentiation between the

U.S. Utility and U.S. Cull grades is based entirely on differences in thriftiness. 

(e) Most feeder pigs are marketed when relatively young and before reaching a weight of 125

pounds. At this age, sex condition exerts little influence on the basic factors determining the

feeder grade. Therefore, these standards are equally applicable for grading barrow, gilt, and boar

pigs, although it is recognized that sex condition may influence the market price in some

instances. It is assumed that boar pigs will be castrated prior to developing the secondary physical

characteristics of a boar. Sows, stags, and mature boars are seldom used as feeder animals, and

these standards do not apply to those classes. 
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(f) Only one combination of muscling and skeletal characteristics is described in the standards

for the U.S. No. 1, U.S. No. 2, U.S. No. 3, and U.S. No. 4 grades. However, feeder pigs

qualifying for the U.S. No. 1, U.S. No. 2, U.S. No. 3 or U.S. No. 4 grades may vary with respect

to the relative development of the individual grade factors. In fact, some will qualify for a

particular grade although they have some characteristics more nearly typical of another grade,

except that feeder pigs in the U.S. No. 1 grade must have at least moderately thick muscling. 

Feeder pigs with other characteristics of the U.S. No. 1 grade, but with less than moderately thick

muscling would be in the U.S. No. 2 grade. Since no attempt is made to describe the numerous

combinations of characteristics that may qualify a feeder pig for a specific grade, making

appropriate compensations for varying combinations of characteristics requires the use of sound

judgment. 

§53.159 Specifications for official U.S. standards for grades of feeder pigs. 

(a) U.S. No. 1. Feeder pigs in this grade near the borderline of the U.S. No. 2 grade are long

and have thick muscling throughout. Thickness of muscling is particularly evident in thick and full

hams and shoulders. The hams and shoulders are thicker than the back, which is well rounded. 

They usually present a well-balanced appearance. In no case may a feeder pig be graded U.S. No.

1 with less than moderately thick muscling. Feeder pigs in this grade are expected to produce

U.S. No. 1 grade carcasses when slaughtered at 220 pounds. 

(b) U.S. No. 2. Feeder pigs in this grade near the borderline of the U.S. No. 3 grade are

moderately long and have moderately thick muscling throughout. Thickness of muscling is

particularly evident in moderately thick and full hams and shoulders. The back usually appears

slightly full and well-rounded. They usually present a well-balanced appearance. This grade also

includes feeder pigs which otherwise qualify for the U.S. No. 1 grade but have less than

moderately thick muscling. Feeder pigs in this grade are expected to produce U.S. No. 2 grade

carcasses when slaughtered at 220 pounds. 

(c) U.S. No. 3. Feeder pigs in this grade near the borderline of the U.S. No. 4 grade are

slightly short and have slightly thin muscling throughout. The hams and shoulders are slightly thin

and flat and the back usually appears moderately full and thick. Feeder pigs in this grade are

expected to produce U.S. No. 3 grade carcasses when slaughtered at 220 pounds. 

(d) U.S. No. 4. Feeder pigs typical of the U.S. No. 4 grade are short and have thin muscling

throughout. The hams are thin and rather flat, particularly in the lower parts toward the shanks. 

The back usually appears slightly flat and the width at the top- line usually is greater than at the

underline. Feeder pigs in this grade are expected to produce U.S. No. 4 grade carcasses when

slaughtered at 220 pounds. 

(e) U.S. Utility. Feeder pigs typical of this grade are small for their age and appear unthrifty. 

They often have a rough, unkempt appearance indicating the effects of disease or poor care. The

hams and shoulders usually are thin and flat and taper toward the shanks. The back is thin and

lacks fullness. Pigs in this grade near the borderline of the U.S. No. 1, U.S. No. 2, U.S. No. 3,

and U.S. No. 4 grades are slightly small for their age and appear slightly unthrifty. It is

recognized that U.S. Utility grade feeder pigs will produce U.S. No. 1, U.S. No. 2, U.S. No. 3, or

U.S. No. 4 grade carcasses when slaughtered at 220 pounds provided their unthrifty condition is
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corrected. U.S. Utility grade feeder pigs whose unthrifty condition is not corrected will produce

U.S. Utility grade carcasses. 

(f) U.S. Cull. Feeder pigs typical of this grade are very deficient in thriftiness because of poor

care or disease. They can be expected to reach a normal market weight only after an extremely

long and costly feeding period, if at all.