Neutral Detergent Fiber (NDF) and its Role in Alfalfa Analysis

The key chemical analysis used to estimate the energy value of alfalfa hay for trading purposes, ADF (acid detergent fiber), has been supplanted by NDF (neutral detergent fiber) as the key chemical analysis used by nutritionists to evaluate the fibrosity and energy value of alfalfa hay for nutritional purposes. It is important that the alfalfa hay trading industry abandon ADF, as it will generally be considered obsolete as an index of hay fibrosity within a few years. Suggestions to move to the RFV (relative feed value) system cannot be supported from an objective evaluation of its strengths and weaknesses. The best choice for the California hay trading industry is to move from ADF to NDF as the key chemical analysis used to estimate the energy value of alfalfa hay for trading purposes. This recommendation is supported by the observations that NDF is widely used by dairy cattle nutritionists, NDF accurately predicts the energy (TDN) value of alfalfa hay, and use of NDF will allow future improvements in biological assays to be added to the TDN prediction equation with only minor changes, and there need be no change in TDN as the base term used to describe the energy value of alfalfa hay. It is important that the chemical predictors of the nutritional value of alfalfa hay for trading and nutritional purposes not be allowed to diverge.