Using ADF and NDF in dairy cattle diet formulation—a western Canadian perspective

Because nutritive value of forages is variable, producers are encouraged to submit samples to commercial feed test labs for chemical analysis. The ADF content can be used to predict the energy content of forage. An appreciation for the analytical variability and the limitations of predicting energy content from ADF is needed to interpret feed analyses reports in terms of animal performance. While predictions of DMI from NDF are poor, the NDF content of forage should be used in diet formulation to ensure adequate fiber. To maximize milk yield and milk fat content, both dietary NDF intake (as a percentage of body weight) and energy intake must be maximized. Diets for high producing dairy cows should be formulated to obtain the highest possible concentration of NDF from forage in the diet, while meeting the requirement for energy density. This can only be achieved by maximizing forage quality.