DIGESTIBILITY AND CELL-WALL CONCENTRATION OF EARLY-MATURING AND LATE-MATURING TIMOTHY (PHLEUM-PRATENSE L) CULTIVARS

Ear emergence or heading of early- and late-maturing cultivars of timo thy (Phleum pratense L.) in the spring varies by as much as 3 wk. Two field experiments were conducted to describe the evolution of digestib ility and cell-wall concentration of early- and late-maturing timothy cultivars during primary growth and to analyze the relationship betwee n parameters of nutritive value and the leaf blade to biomass weight r atio (LWR). Compared with late-maturing cultivars of timothy on a give n date, early-maturing cultivars had lower in vitro true digestibiliti es of DM and cell wall and a greater NDF concentration. Differences in in vitro true DM digestibility and NDF concentration between early- a nd late-maturing cultivars were not only related to the proportion of leaf blades in the biomass. Different parameters are, therefore, requi red to describe the mathematical relationships between digestibility a nd NDF concentration and LWR of early- and late-maturing cultivars.