Alfalfa Morphological Stage and its Relation to in Situ Digestibility of Detergent Fiber Fractions of Stems

Digestibility of NDF [R 2 =0.78, root error mean square (REMS)=64 g kg −1 ], cellulose (R 2 =0.78, REMS=58 g kg −1 ), and hemicellulose (R 2 =0.83, REMS=59 g kg −1 ) declined nonlinearly with increasing maturity stage. Digestion rate of NDF, cellulose, and hemicellulose was faster in vegetative stems (average=0.164 h −1 ) compared with reproductive stems (average=0.093 h −1 ). Hemicellulose was digested 80% faster than cellulose. Our data demonstrated a close association between in situ digestibility of detergent-fiber fractions and the Cornell index and further supports its utility