
Forage should make up the bulk of the equine diet, with horses requiring at least 1.5% of their body weight in forage daily. In addition to meeting this fiber requirement, hay can also provide a large proportion of some of the horse’s daily nutrient requirements. The nutrient contributions will depend on the nutrient profile, which will vary based on several factors regarding the hay itself.
A common myth is that we can use the cutting of a hay to predict its nutrient profile, however, due to the factors that impact nutritional value, cutting is not enough! 1st cut hay can be of high nutritional value depending when the hay was harvested, while 2nd cut can also be of reduced nutritional value due to weather stress impacting growth and harvest time. The most reliable method to gain insight into a hay’s nutrient profile is hay testing and analysis.
However, once a hay analysis report has been acquired, it can be difficult to interpret - but that’s where we want to help! Read more to learn more about common data points on a hay analysis report, what these values might mean nutritionally, and how to interpret the hay analysis for YOUR horse.
Part I: Dry Matter & Moisture on a hay analysis report

Dry Matter (DM)
Definition: Includes the part of the feed which is not moisture/water to indicate the amount of measured values present. This allows us to compare different feedstuffs more accurately, as the dilution effect of water content has been removed.
Normal: 90-93%
Too low: Values below 85% may be too high in moisture, increasing susceptibility to mold & combustion.
Too high: Values above 90% can indicate increased leaf loss. As nutrients are stored in leaves, this can result in a lower nutrient profile.
Moisture
Definition: The amount of moisture in the hay, so the direct counterpart to dry matter.
Normal: 10-15%
Too low: <10% may indicate leaf shattering and loss, which will mean less nutrients in the hay.
Too high: >15% increases the risk of mold, >20% increases risk of combustion and fire risk. Hay baled when moisture is high can also reduce protein utilization and palatability.
Part II: Digestible Energy, Digestibility & Determining NSC Suitability from a hay analysis report.
Digestible Energy (DE, Mcals/kg or Mcal/lb)
Definition: The amount of energy (calories) that can be digested and used by the horse, often in Mcals, which is 1000 Calories (kcals, the unit commonly used in human nutrition). NOTE: Make sure to select a forage analysis package that includes DE for horses.
Normal: Can range from 1.67 to 2.4 Mcal/kg depending on the type and quality of hay.
Too low: This will depend on your horse’s requirements and body condition. For horses in work, values below 2.0 Mcal/kg may not meet their energy requirements, depending on intake.
Too high: This will depend on your horse’s requirements and body condition. For overweight horses, values over 1.70 Mcal/kg may over-provide calories at free choice intake, depending on intake.

Tip: Knowing your horse's body weight, workload, life stage, and body condition score can allow you to assess if a hay will meet your horse's requirements.
Total Digestible Nutrients (TDN)
Definition: An estimate of the relative energy content in the hay, however is not used often in horses as it was developed for other livestock (cattle).
Normal: Ranges from 40-68% depending on species of grass or legume.
Too low: Lower values are considered lower quality.
Too high: Higher values are considered better quality.
Crude Protein (CP)
Definition: An approximate value of protein content, estimated by nitrogen content. This value does not tell you about protein quality, which is dictated by amino acid composition.
Normal: 8-20% depending on hay quality and type.
Too low: <8-12% may require protein supplementation depending on the horse’s requirements, intake, life stage and workload.
Too high: >18% will over provide protein in most cases
Acid Detergent Fiber (ADF)
Definition: Refers to the indigestible cell wall portion of the plants in hay (cellulose and lignin).
Normal: 30-40% easily digested.
Too low: <20% may not provide sufficient fiber for hindgut health.
Too high: >45% will have low nutritional value, reduced palatability, and may increase the risk for digestible disturbances.
Neutral Detergent Fiber (NDF)
Definition: Cell wall fraction that includes ADF and hemicellulose (insoluble fibers).
Normal: 40-60%
Too low: <28%, will not meet fiber requirement, may compromise digestive health.
Too high: >65% likely to reject due to reduced palatability, and can increase risk of digestive complications.
Relative Feed Value (RFV)
Definition: Overall score for your hay based on digestibility and calories. Less used in equine nutrition but may be useful for referencing.
Normal: 75-180 range depending on hay type, maturity and quality.
Too low: Below 90 to 100 often won’t meet the needs of working horses, depending on intensity and individual requirements.
Too high: Above 90 may oversupply calories to overweight horses.
Non-Structural Carbohydrates (NSC)
Definition: Simple sugars and starches in the hay.
Normal: 8-20% depending on the hay.
Too low: Low NSC content in hay is not a huge cause for concern.
Too high: >10-12% is not appropriate for horses with metabolic disorders, laminitis, or PSSM.

Part III: Looking at minerals on a hay analysis report, and minimum amounts required to meet basic needs.
Other values - Minimum minerals to cover maintenance requirements (500 kg mature horse not in work - note that requirements change depending on workload, body weight, and life stage).
Calcium (Ca): 0.2%
Phosphorus (P): 0.1%
Magnesium (Mg): 0.1%
Potassium (K): 0.3% - NOTE: Usually oversupplied by hay.
Sodium (Na): 0.1%
Chloride (Cl): 0.4%
Sulfur (S): 0.2%
Cobalt (Co): 0.05 ppm
Copper (Cu): 10 ppm
Iodine (I): 0.35 ppm
Iron (Fe): 40 ppm - NOTE: Usually oversupplied by hay.
Manganese (Mn): 40 ppm
Selenium (Se): 0.1 ppm
Zinc (Zn): 40 ppm
*ppm = parts per million, or mg/kg.
It is important to remember that these are just the minimum amounts to meet requirements, and that minerals also need to be balanced appropriately for proper function. The minerals in your horse’s hay will not be perfectly balanced, but your hay analysis results can help you identify where additional balancing is required.
Need a hand with your hay test? At Honos Nutrition Co., we can help you:
Locate your nearest testing lab if you want to do your forage sampling yourself.
Assess forage suitability on an existing hay analysis report.
Collect a forage sample for testing and transport it to the testing lab, then help you interpret & balance the results (standalone service, and also included in some nutrition consulting plans).
Coming soon: more forage-related resources ;)
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