Digestibility and cell wall concentration of early- and late-maturing timothy (Phleum pratense L) cultivars

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