With over 80,000 head of horses in the state of Georgia, horse owners are looking for efficient and nutritional forage options.  Horses are naturally meant to consume a forage-based diet and on average, should consume at least one percent of its body weight in forages.  In most instances, pasture and hay should make up the majority of the average horse’s diet.  Producers may or may not need to incorporate grain, depending on the quality of their hay.  Forage testing is an excellent way to determine how well your forages can meet the nutritional needs of your horses.  When it comes to selecting hay, many people assume that high quality hay smells good and is soft, and has more leaves than stems, but visual observations often make little known about the actual nutrient value of your forages. 

Forage testing conducted by the University of Georgia provides accurate information about the quality of your forages. These days, it is relatively easy to obtain a hay analysis.  The most important step in obtaining a meaningful analysis is to collect a representative forage sample. Extreme variation may occur in hay quality even when harvested from the same field. As a result, a separate forage sample should be tested for each hay “lot.” A “lot” refers to a quantity of similar forage harvested on the same day, from the same field, under uniform conditions.  For best results it is recommended to use a hay bale corer for sample collection.  For round bales select a minimum of 10 – 20 representative bales and collect a core from the round side of each. Combine the cores in a bucket and mix well. Large round bales should be sampled to the center using a long probe or one with an extension adapter. Angle the probe in an upward direction to reduce the potential for water entering the core holes. When sampling small square bales, select 20 bales and sample from the end at a straight inward line. Place the sample to be tested in plastic zip lock bag and label before taking to Extension office. Bags should be labeled with your name, lot name, date harvested, and species of grass.

With results that are full of abbreviations, numbers and percents, understanding the hay analysis can be tricky.  Typically, there are two columns in a hay analysis, “as is”, “as fed” or “as sampled”, and the other will read “DM” or “Dry Matter”.  “As Sampled” refers to the sample’s nutrient values before adjusting for water content.  Since samples vary in water content, deducting the amount of the total sample weight contributed to water allows samples to be compared more accurately.  “Dry Matter” basis refers to the nutrient values after the water was deducted.  When comparing values between forages or comparing values to an animal’s requirements, you will use the dry matter basis value. 

Key nutrients and information listed on hay analysis:

Moisture and Protein

An accurate analysis of moisture is important for estimating total forage intake.  For horses, the ideal moisture is around 15%.  If moisture is less than 10%, they hay will lose a lot of nutritious leaves to shattering, while the risk of mold, or spontaneous combustion is much greater if the moisture is above 20%.  Crude protein is determined by measuring the nitrogen content of forage. For adult horses, adequate protein should be provided by the hay if the crude protein value ranges from 10-12%.  If you have young horses, high-intensity exercise or broodmares that are lactating, you will want a higher CP in your forage.  Note that legumes such as alfalfa will  have higher CP as compared to grass hays, but maturity of the plant when the hay was harvested will also impact CP. Excessive heat generated in bales with high moisture can cause protein to bind to fiber, reducing digestibility. 


Carbohydrates fall into two categories: structural carbohydrates (fibers) and non-structural carbohydrates (sugars, starch, etc.).  Neutral Detergent Fiber and Acid Detergent Fiber make up the amount of fiber in hay.  The more mature the plant, the higher amount of fiber it will contain.  Neutral Detergent Fiber (NDF) measures the plant’s cell wall content, shown as a percent.  The higher the percentage, the less likely the horse is to eat it.  The ideal NDF ranges from 40-65%.  Acid Detergent Fiber (ADF) refers to cellulose and lignin concentration, shown as a percent.  As ADF increases, digestibility and nutrient availability decreases.  The ideal ADF for horses ranges from 30-45%. For horses that need to lose weight or are considered easy keepers, you may want NDF and ADF values to be on the higher end of the ideal ranges.  For horses that require more calories, like young or working horses, you may want a lower NDF and ADF.

Non-Structural carbohydrates measure the non-fibrous carbohydrates.  There is not an ideal NSC number for horses, however, for horses that suffer from chronic laminitis or other metabolic disorders, it is recommended to keep NSC below 10-12% (DM basis).  For horses that need to lose weight, you may also want a lower NSC.   

Nutrient and Energy Value

Total Digestible Nutrients (TDN) is an expression of energy and is the most useful number in comparing forages.  The number estimates the protein, fat, and carbohydrate in the forage that can be digested by the animal.  It is important to correctly identify forage species when submitting samples as TDN is predicted from equations developed for different classes of forages.  TDN is commonly predicted from CP and ADF.  Monitoring TDN can help determine if forages need to be harvested earlier to increase digestibility and energy supply. 

What else might you find on a hay analysis?

You might also see something called RFQ, or Relative Forage Quality.  , This number approximates the quality of the hay and allows for comparison across multiple species. It is commonly used to characterize, rank and even price forages based on their potential feeding value. The value of 100 refers to full bloom alfalfa.  The higher the RFQ, the better quality the hay.  RFQ places more emphasis on the potential impact of NDF and ADF values.

Remember – The ideal amount of certain nutrients will vary for each horse, and is impacted by factors such as health, activity/exercise, age, and body condition.  Understanding the hay analysis is important in making sure your horse has a well-balanced diet.  You should select hay based on your horse’s needs.

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