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Hay Evaluation and Testing

  • Factors that affect hay quality
  • – Species (Cool/ Warm Season, Legumes, Annuals)
  • – Curing process (baled at proper moisture, no rain, etc.)
  • – Soil fertility
  • – Stage of maturity at harvest
  • Generally more mature forage means lower quality
  • Condition
  • – Avoid musty, dusty or moldy hay
  • – Avoid hay with foreign materials-weeds, trash, etc.

Evaluating hay based on color

Color Problem Quality
Green None Usually good
Light yellow on outside of bale Sun bleaching Decreases palatability and carotene, but not serious
Yellow throughout Over-mature when cut Decrease in palatability, horses may not eat it
Dark brown or black Rain, heavy dew or fog Decreased nutrient content, leaf shattering, brittle
Brown Mold growth, baled too moist Musty, moldy, loss of nutrients, clumps

Sampling Hay

  • NC Feed Testing Service-NCDA&CS
  • Free-Single tests for Nitrates, Aflatoxin, & Mycotoxin
  • $10-Complete Analysis (TDN, Protein, Fiber, etc.)
  • NCDA Forage test form

A hay sample is only as good as the sampling technique. Best results are obtained when a core sampler is used to sample the hay. These are available at most county Extension offices. Regardless of the sampling technique, you will want to obtain a sample from each unique “lot” of hay. A lot is considered hay from the same field and the same cutting that was cured and stored under the same conditions.

If a core sampler is used, take cores from 10-15 bales or enough cores to fill a quart-sized plastic bag. Always sample from the end of square bales or the sides of round bales.

If a core sampler is unavailable grab samples can be tested. The best way to do this is to open several bales and grab portions from the center to tightly pack a gallon-sized plastic bag. This test will not be as accurate as one obtained with a core sampler, but it is still useful.

After obtaining the sample you can mail, ship or deliver it to the forage lab along with payment, if applicable. The addresses are on the forage test form (see link above.)

Sample Hay Analysis

John Doe                      Telephone # 919-555-1234

Box 549, Stump Wallow, NC 55555           Harnett County

Sample number:                     1001

Description:                             Hay, Second cutting

Forage type:                            Bermudagrass

Species:                                  Horse

Production stage:                    Maintenance

Laboratory Results                   As Fed Basis                   Dry-matter Basis

Dry Matter %                            91.08

Crude Protein %                       7.55                                          8.29

Unavailable Protein %              0.36                                          0.40

Adjusted Crude Protein %        7.55                                          8.29

Acid Detergent Fiber %            33.46                                        36.74

TDN %                                      57.61                                        63.25

NE (lactation), Mcal/lb               0.49                                         0.53

Sodium %                                  0.02                                         0.02

Potassium %                             1.70                                         1.87

Calcium %                                 0.18                                         0.21

Magnesium %                           0.14                                          0.15

Phosphorous %                         0.15                                         0.16

Sulfur %                                     0.15                                         0.17

Iron, ppm                                   191.00                                     210.00

Zinc, ppm                                   31.00                                       34.00

Copper, ppm                              7.00                                         8.00

Manganese, ppm                       80.00                                       88.00

Nitrate ion, %                             0.07                                          0.08

Interpretation of Hay Analysis

Test results are given on  As-Fed and Dry Matter basis. The Dry Matter Basis column reflects the content of the sample after all water is removed. It is best to compare two different samples on a dry matter basis as this more accurately reflects the nutrient content of the feed.

The first result given is Crude Protein. This is an especially important nutrient for young, growing livestock or gestating animals. Legume hays, such as alfalfa, generally have higher protein values than grass hays such as fescue or bermudagrass. Within a species, forages harvested at later stages of maturity generally have lower protein values. Protein will also be somewhat less on a hay that was exposed to rain or heavy dews during the curing process. Unavailable Protein refers to protein bound to fiber.

Acid Detergent Fiber is an indicator of the digestibility of the hay. For horses, higher ADF values mean decreased digestibility. Average ADF values for grass hay are around 30-37 %. ADF value greater than 40% indicates low energy content and low digestibility.

Nitrate Ions are the common form of Nitrogen found in fertilizers. Nitrate poisoning can occur if livestock consume forage with too much nitrate ion, as it decreases the ability of the animal’s blood to transport oxygen. Forages containing less than 0.5% nitrate ion are safe. Forages containing 0.5% to 1.25% nitrate ion can be fed if supplemented with sufficient grain or non-nitrate containing forage! Forages containing more than 1.5% nitrate ion should not be fed.