Price-quality relationships for alfalfa hay were analyzed by hedonic pricing models using 1996-2001 Wisconsin auction data. Individual nutrients included in the analysis all affected alfalfa price, with acid detergent fiber accounting for the largest impact. Alternative pricing models, based on an aggregate quality index or detailed quality information, were similar in their ability to predict price. However, disaggregating price predictions to account for differences in relative feed value (RFV) and crude protein (CP) indicate that both RFV and CP are important determinants of price and that aggregating the two into a quality index is not warranted.