Forage and feed testing involve measuring nutrient levels in forages and feeds. This process is one of the most important feed and forage management tools.
Such testing takes the guesswork of trying to match forage and feed supplies to animal nutrient requirements. It also helps design supplemental feeding programs and evaluating forage requirements.
A standard hay test will analyze moisture, protein, fiber and various minerals. Moisture is the amount of water in a sample with most samples containing between 10 to 15 percent moisture. Within the hay analysis report is a column labeled as-is or as-fed. Another column is labeled as dry matter. When you divide the as-fed number by the percentage of dry matter in a sample it converts the results to a dry matter basis. When you use the results of dry matter, you get an accurate comparison between wet and dry feeds because the water content of the hay is not included in the report’s dry matter nutrient results.
Protein is the nutrient most people want to know about. Crude protein is estimated by measuring the amount of nitrogen in the sample and multiplying it by 6.25. The reasoning behind this is the fact that most forage stem and leaf tissue proteins contain 16 percent nitrogen. While higher crude protein is superior, it must be considered in the context of things like fertilizer rate, nitrate concentrations, plant maturity and species. Fiber analysis is another important component of a hay analysis. Forage samples are boiled in a neutral or acid detergent solution during which the digestible portions of the sample disappears while the indigestible portions remain. The residues are then reported as Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF). NDF estimates forage intake while ADF calculates estimated energy levels in the forage. These energy estimates are listed as Total Digestible Nutrients, Net Energy maintenance and Net Energy gain. NDF and ADF results are residues so lower numbers indicate greater intake potential and higher energy levels.
The final component of most hay tests is a mineral analysis. In most cases, calcium and phosphorus are included in a hay test package. Some labs also include potassium and magnesium. You also can request that other minerals be measured but will be charged for these measurements.