Winter “feeding season” is upon us, and with that comes a list of questions related to the appropriate type of feed to select, amount to provide and frequency of feeding. What if I told you that you might not have to provide supplemental feed, or the amount of feed you need to provide is less than you think?

Mullenix kim
Extension Beef Specialist and Associate Professor / Auburn University

There are many good articles out there on the importance of forage testing and how it can help us better optimize our winter carrying costs in cattle operations. However, rather than using forage testing as a tool to tell us what to supplement, what if we used it to tell us potentially what we don’t have to supplement if forage quality is high? A $15 to $20 investment in a forage analysis can potentially save thousands in terms of supplemental feed costs.

Forage analysis components often include dry matter (moisture), total digestible nutrients, crude protein (CP), fiber, nitrate-nitrogen, relative forage quality (RFQ) and mineral concentration. When reviewing a forage analysis report, interpretation is based on the “dry matter basis” column. Comparing forages on a 100% dry matter basis allows for a more equal comparison among forage types. CP is the total nitrogen in a forage sample multiplied by a 6.25 correction factor. Protein is important for growth, milk production and muscle development. Most moderate to high-quality hay has more than sufficient CP to meet cow nutrient needs, which can potentially eliminate the need for protein supplement. Instead, energy is often more limiting in Southeastern forage-based diets.

Energy value of a forage is expressed as total digestible nutrients or “TDN.” Typically, the greater the value, the more energy-dense the forage is considered. The relative forage quality or “RFQ value” is a unitless index which combines an estimate of predicted forage intake and digestibility. This is a single number that can be used to compare the overall quality of one or more forage samples. In general, RFQ values range from 0 to 300+, with the upper end representing the highest-quality forage. The higher the nutrient demands of the animal, the higher-quality forage needed to support animal performance. In general, an RFQ of 110 to 120 will meet the needs of most cow-calf operations.

Using these values can help producers better assess nutritional value of forage used in the winter months and identify if supplementation is even needed. Additional information can be found on the “Interpreting a Forage Analysis for Beef Cattle” fact sheet on the Alabama Cooperative Extension system website.