Submitted to: American Forage and Grassland Council Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 25, 2001
Publication Date: May 20, 2001
Citation: Moore, J.E., Coleman, S.W. 2001. Forage intake digestibility, ndf, and adf: how well are they related?. American Forage and Grassland Council Conference Proceedings. 2001 vol.10 p.238-242
The conventional wisdom is that there are close relationships between voluntary forage dry matter intake (DMI) and digestible dry matter (DDM) concentration, DMI and NDF, and DDM and ADF. Published correlation coefficients (r) between DMI and DDM range from -.32 to 0.86, suggesting that DMI and DDM are often independent components of forage quality. Also, it has been shown that intake of NDF is not a constant among forages fed alone. Many forage testing programs use simple regression equations to predict DMI from NDF and DDM from ADF. Van Soest (1965) reported r = -.65 between DMI and NDF, and r = -.74 between DDM and ADF (n = 83). Since then, published r values have ranged from 0.03 to -.90 between DMI and NDF, and from -.39 to -.93 between DDM and ADF. We conclude that routine forage testing programs using only NDF and ADF may often provide unacceptable estimates of DMI and DDM, for both grasses and legumes.