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Corn grain is a major cereal grain used to supply energy in livestock diets. Considered the “gold” standard for cereal grains, corn grain offers a palatable energy source that is low in fiber. It contains no major antinutritional factors and can be fed with minimal processing. Ruminants efficiently consume whole, lightly cracked, rolled, or steam-flaked corn, while both swine and poultry consume corn that is rolled to a ground size of 600-900. Corn grain also works in some aquaculture and companion animal diets.


Corn is divided into three classes based on color: Yellow corn, White corn, and Mixed corn. Each class is divided into five U.S. numerical grades and U.S. Sample Grade. Special grades are provided to emphasize special qualities or conditions affecting the value and are added to and made a part of the grade designation. They do not affect the numerical or sample grade designation.


 

Grades and grade requirements for corn.

 

Grade

Minimum test weight per bushel (pounds)

Maximum limits of:

Damaged kernels (percent)

Broken corn

and foreign

material

(percent)

 

Heat damaged

kernels

(percent)

 

Total

(percent)

 

U.S. No. 1

U.S. No. 2

U.S. No. 3

U.S. No. 4

U.S. No. 5

 

56.0

54.0

52.0

49.0

46.0

 

0.1

0.2

0.5

1.0

3.0

 

3.0

5.0

7.0

10.0

15.0

 

2.0

3.0

4.0

5.0

7.0

 

U.S. Sample Grade

U.S. Sample grade is corn that:

(a) Does not meet the requirements for the grades U.S. Nos. 1, 2, 3, 4, or 5; or

(b) Contains stones with an aggregate weight in excess of 0.1 percent of the sample

weight, 2 or more pieces of glass, 3 or more crotalaria seeds (Crotalaria spp.), 2 or more

castor beans (Ricinus communis L.), 4 or more particles of an unknown foreign

substance(s) or a commonly recognized harmful or toxic substance(s), 8 or more

cockleburs (Xanthiumspp.), or similar seeds singly or in combination, or animal filth in

excess of 0.20 percent in 1,000 grams; or

(c) Has a musty, sour, or commercially objectionable foreign odor; or

(d) Is heating or otherwise of distinctly low quality.

 

 
 

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