FORAGE QUALITY OF 5 COOL-SEASON GRASSES .2. SPECIES EFFECTS

A 2-year field experiment was conducted on established stands of smooth bromegrass (Bromus inermis Leyss.), orchardgrass (Dactylis glomerata L.), timothy (Phleum pratense L.), tall fescue (Festuca arundinacea Schreb.) and reed canarygrass (Phalaris arundinacea L.) to evaluate maturity effects on quality. Herbage was sampled on seven dates during spring and early summer. Species did not differ in total N and all declined in N with shoot maturation. Timothy was highest in average in vitro dry matter disappearance (IVDMD) at 661 g kg-1 and orchardgrass was lowest at 615 g kg-1. Reed canarygrass and tall fescue declined more rapidly in IVDMD with maturation than timothy and smooth bromegrass. Orchardgrass had the highest average neutral detergent fiber (NDF) concentration at 624 g kg-1. Tall fescue had the lowest average NDF concentration, at 576 g kg-1, but reed canarygrass increased more rapidly in NDF with maturation than smooth bromegrass and timothy. Results of this experiment indicate that reed canarygrass and, to a certain extent, tall fescue changed more rapidly in IVDMD, NDF and acid detergent fibre (ADF) with maturation than the other species and thus would need to be utilized at an earlier stage of maturity to obtain forage of similar quality. Timothy and smooth bromegrass declined least rapidly in quality. Timothy had the highest average IVDMD, but tall fescue had a lower average NDF concentration indicating that species differences also exist in cell-wall digestibility. © 1990.