Use of forage analyses and the three dairy diet formulation programs has assisted Wisconsin dairy farmers to make greater progress toward highly competitive, profitable dairying. Acid· detergent fibre (ADF) has proven very satisfactory in predicting forage energy value. The equation to predict digestible dry matter (DDM = 88,9 – 0,779' ADF)has been in use for over 2 years and has been well accepted as an estimate of net energy· lactation or TDN for dairy diets. Neutral-detergent fibre (NDF) has been incorporated into the Badger Balancer (BB) and Total Mixed Ration (TMR)formulation programs with increased farmer satisfaction and animal performance when feeding the resulting diets. Use of 21% NDF from forage in the total diet dry matter has worked well to specify minimum forage in the milking cow diet. Using NDF to specify maximum forage in lactating cow diets has simplified dairy diet formulation. When using NDF to specify maximum forage, one must no longer use rule of thumb or other arbitrary limits to limit the contribution from low ADF and high NDF forages such as corn silage and grasses.