CLASSES


 There are five classes of slaughter andfeeder swine. Definitions
of the respective classes are as follows:
 BARROW.--A barrow is a male swine castrated whenyoung and
before development of the secondary physical characteristics of
a boar.
 GILT.--A gilt is a young female swine that has not produced
young and has not reached an advanced stage of pregnancy.
 SOW.--A sow is a mature female swine that usually shows
evidence of having reproduced or having reached anadvanced stage
of pregnancy.
 BOAR.--A boar is an uncastrated male swine.
 STAG.--A stag is a male swine castrated after development
or beginning of development of the secondary physical charac-
teristics 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.

 GRADE FACTORS
 The grade of a feeder pig is determined by evaluating two gen-
eral value-determining characteristics--its logical slaughter po-
tential and its thriftiness.
 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.
 Thriftiness in a feeder pig is its apparent ability to gain weight
rapidly and efficiently. Size for age, health, and other general indi-
cations of thriftiness are considered in appraising the thriftiness of
feeder pigs.

 GENERAL PRINCIPLES

 The standards provide for five grades of feeder pigs-- U.S. No. 1,
U.S. No. 2, U.S. No. 3, Medium, and Cull--corresponding in name to
the five grades for slaughter swine and pork carcasses. The No. 1,
No. 2, and No. 3 grades include all pigs which are thrifty. Differ-
entiation between the No. 1, No. 2, and No. 3 grades is based
entirely on differences in logical slaughter potential. Feeder pigs
in the No. 1 grade have sufficient muscling and frame to reach
a market weight of 220 pounds with near the minimum degree of
finish required for the production of cuts with acceptable quality
characteristics. Feeder pigs in the No. 2 and No. 3 grades usually
have progressively less muscling and less frame and are expected
to have progressively more finish when marketed at 220 pounds.
The Medium and Cull grades include only pigs which lack thriftiness.
Differentiation between these grades is based entirely on differences
in degree of unthriftiness.
 Most feeder pigs are marketed when relativelyyoung and before
reaching a weight of 125 pounds. At this age, sex condition exerts


-2-