How to Interpret Your Hay Test

For the purposes of evaluating the hay for your horse you will most often consult the Dry Matter Basis column. Both sets of numbers represent the actual amount of the specific nutrient in the hay but the As Fed column is reported with the values expressed as a percentage of the feed including the weight of the moisture in it. The Dry Matter Basis column is reporting the nutrients expressed as a percentage of the feed without the moisture included. Every feedstuff has moisture...some have more than others. 
Crude Protein
Crude protein is an estimation of the total protein content of a feed. It is determined by analyzing the nitrogen content of the feed and multiplying the result by 6 25. Protein in some feedstuffs such as grass silage or haylage can be further differentiated by criteria such as protein digestibility and protein quality. Generally grass or alfalfa hays that are 90 percent or higher in dry matter and were harvested at a prebloom or preboot stage contain a high quality protein of superior digestibility. 
The requirement for protein in horse hay will vary depending on what other feeds are being offered the work level of the horses and their metabolic state i e. growing mature breeding stallion lactating mare etc. The protein requirements of horses are well documented in the National Research 
ADF NDF Lignin
The terms ADF and NDF stand for Acid Detergent Fibre and Neutral Detergent Fibre respectively. These terms refer to the cell wall portions of the forage that are made up of hemicellulose cellulose and lignin. These values are important because they give an indication as to the ability of the horse to digest the hay to its component nutrients. As forage matures the ADF NDF and lignin values tend to increase. As ADF NDF and lignin increase digestibility of hay usually decreases. The energy measurements such as digestible energy DE reported on your hay analysis are calculated using the ADF NDF and lignin values.
ESC WSC Starch NSC
The values for ADF NDF and lignin are all used to help quantify the cell walls in your hay test. The terms ESC WSC Starch and NSC are all used to describe the cell content portions of the hay. The terms ESC and WSC stand for ethanol soluble carbohydrate and water soluble carbohydrate respectively. ESC is a measure of the very simple sugars and WSC is a measure of the