Understanding Your Hay Analysis

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A hay analysis will help you best understand what you are feeding your horse and how to best meet their individual nutrient needs. An analysis is especially important if you’re trying to manage certain nutrition-related diseases or disorders like EMS, Cushing’s or PSSM. When sending in samples, always request an equine analysis so you get equine-specific data, such as digestible energy (DE). With some labs, you may also have to specify tests to determine nonstructural carbohydrates (NSCs).

The first reading on your report will likely be the percent moisture in the sample. Optimal horse hay moisture ranges from 10 to 15%. Above 15%, there is an increased risk for molding and above 25% there is a risk for heat damage and a potential fire hazard. Below this reading, the analysis results will be reported in two columns: As-sampled (or as-fed) and Dry Matter. As- sampled reports the nutrients in their natural state, including moisture. The dry matter column reports nutrients with moisture removed and is easier to compare the nutrient percentages across various samples. It is recommended to use the dry matter column.

Digestible energy (DE) is the measure of energy or calories in the sample. The average grass hay is about .91 Mcal/lb. A horse in light work (1-3 hours per week) requires about 20 Mcals per day. If using this grass hay as an example, an average sized horse would need about 22 pounds of hay per day to meet this energy requirement.

Crude Protein (CP) is a measure of the protein content in the hay and is an indicator of the amino acid concentration. The common range for grass hays is 8-14% CP and 15-20% in legume hays. Most horses have a crude protein requirement of about 10-12%. Lysine is an amino acid, of which horses have a specific dietary requirement. An average sized horse in light work requires about 30 g of lysine per day. Grass hays will likely need to be supplemented to meet this requirement.

Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF) help determine the amount of indigestible fiber and insoluble fiber in the sample. ADF values below 45% in general are suitable for horses. NDF measures structural carbohydrates or cell wall and is directly correlated with preference and consumption. The higher the value, the less the horse will eat. Values above 65% will not be readily consumed by horses. Higher NDF hays could be used to rate consumption for easy keepers. Both ADF and NDF are an indicator of plant maturity. Higher values are associated with more mature, less digestible forage.

Water Soluble Carbohydrates (WSC) includes monosaccharides, disaccharides and some polysaccharides (mainly fructan), while Ethanol Soluble Carbohydrates (ESC) measures monosaccharides and disaccharides. Nonstructural Carbohydrates (NSCs) is a measure of starches and sugar and is commonly estimated by adding WSC and starch. For horses with metabolic syndrome, NSC in the diet should be limited to 10-12%.

Calcium (Ca) and phosphorus (P) are the two minerals needed in the greatest amount in the equine diet. A horse in light work requires about 30g of Ca and 18g of P per day. Also, the ratio of Ca:P in the diet needs to be 3:1 to 1:1, and P should never be higher than Ca to avoid potentially severe orthopedic diseases.

Relative Feed Value (RFV) is a calculation used as a quick-comparison method between hays, but isn’t used for balancing rations. Average quality alfalfa is set at 100.

As always, if you need help interpreting your hay analysis or selecting a hay for your horse, please contact me at 828-894-8218 or cassie_lemaster@ncsu.edu.