Fig. 2. Comparison of regression models used to estimate the neutral detergent fiber (NDF) of the alfalfa component of mixed stands. The equations used are PEAQ (Hintz and Albrecht, 1991), NYPQ (Cherney and Sulc, 1997), NYHT (Parsons et al., 2006a), and NYGD (Parsons et al., 2006a). The line from lower left to upper right is the 1:1 unity line indicating a perfect fit.