Harvested feeds are beginning to make their way out of the fields to be stored for feeding livestock. Rations will be developed based on what feedstuffs are stockpiled, but how do you know the nutritional profile of a feed? A well-made ration will be formulated from feeds that have been laboratory tested. Nutrient values in feeds will differ year-to-year and potentially field-to-field. To meet livestock production goals, we need to ensure they are getting the correct nutrients in their feed.
Important Report Components
DRY MATTER AND MOISTURE
Dry matter is valuable to know when developing a feeding program. The DM content of a diet needs to be monitored to ensure that the animal can consume the allotted feed that is providing the daily nutrients. A diet on paper may check all the boxes for nutrient levels; however, with low levels of dry matter, feed intake may lag behind what is needed. Laboratories provide a detailed report separating each nutrient into two categories: dry matter basis or as received. Dry matter basis values represent the nutrient content in that feed when no water remains, and these values are used in developing a ration. Dry matter content will be higher than the as received value due to the lack of dilution factor from water content.
PROTEIN
On a feed analysis report, protein is typically reported at crude protein (abbreviated as CP). This is a measurement of the nitrogen content of a feedstuff. Crude protein can be divided further into different categories, such as rumen degradable and rumen undegradable proteins. For additional information on understanding protein in feeds, see the article, Understanding Protein in Feed, and for rumen degradable and rumen undegradable proteins, see the article, Rumen Degradable Protein Versus Rumen Undegradable Protein.
Protein is a macronutrient that impacts, not only animal growth, but rumen health. A minimum of 7% crude protein is needed by a dry, mature cow, which is required to maintain rumen microbe populations. If this protein threshold is not met, digestion is impacted, especially for roughages. In feedlot rations, protein levels typically are higher to support rapid muscle growth in these animals.
ENERGY
If our animals are receiving a ration deficient in energy, they simply will be unable to meet our expectations and desired performance goals. Growing and finishing cattle will gain more slowly than desirable, which may impact marketing windows and profitability. Insufficient energy supply for the cowherd will reduce milk production and body condition score. These changes may affect calf weaning weight and subsequent reproductive success.
FIBER
Fiber is split into Neutral Detergent Fiber (abbreviated as NDF) and Acid Detergent Fiber (abbreviated as ADF). Both can provide insight into the digestibility and nutrient availability of a feed. Both values are reported as percentages. Neutral Detergent Fiber is a predictor of the rumen fill and, in turn, the voluntary intake of that feed. Low NDF values are desired, since NDF increases as the forage matures; indicating that an animal may not be able to ingest enough feed to meet their requirements. Acid Detergent Fiber is the portion of fiber that is composed of cellulose and lignin and correlates directly to digestibility. A lower ADF value indicates greater digestibility, as there are fewer indigestible compounds in the feedstuff.
Conclusion
Feed analysis may seem like an extra and unnecessary expense; however, feed testing is an important tool for developing rations that support desired livestock’s growth and development. Nutrient values are not the same year-to-year. There may be some similarities, but different weather patterns, fertilizing methods, harvest time, and various other factors can impact the nutrient value for harvested feeds. Well-developed rations begin with knowing information about each of the feeds utilized within them.
