Differences between related grasses, times of year and plant parts in digestibility and chemical composition

Abstract

SUMMARYTrue dry matter digestibility, proportion of cell content, digestibility of cell wall, N and water-soluble carbohydrate were determined in eight related grasses in February, June and September in each of three years. In a separate experiment, true dry matter digestibility, proportion of cell content and digestibility of cell wall were determined in five plant parts of vegetative tillers of two grasses in February, April, June, August, October and December in each of two years.Perennial ryegrass (Lolium perenne) was the most digestible grass and tall fescue (Festuca arundinacea) and Westerwolds ryegrass (Lolium multiflorum var. Westerwoldicum) were the least digestible. Italian ryegrass (Lolium multiflorum) was high in proportion of cell content, but not in digestibility of cell wall. Meadow fescue (Festuca pratensis) was high in digestibility of cell wall, but low in proportion of cell content. Perennial ryegrass and hybrid ryegrass were high, and tall fescue low, in both proportion of cell content and digestibility of cell wall. Ryegrasses were lower than fescues in concentration of N and higher than the fescues in water-soluble carbohydrate; ryegrass × meadow fescue hybrids were intermediate between the parent species in N and watersoluble carbohydrate.Grass sampled in June and August was lower in both proportion of cell content and digestibility of cell wall than grass sampled at cooler times of year. Grass sampled in February was high in proportion of cell content and N, intermediate to high in digestibility of cell wall and intermediate in water-soluble carbohydrate.Expanding leaf blades of perennial and Italian ryegrass were higher than expanded blades and sheaths in digestibility of cell wall and similar to expanded blades and higher than sheaths in proportion of cell content. Cell wall was less digestible in the tip than in the middle and basal portions of expanded leaf blades.

Effect of Defoliation Management on Water‐Soluble Carbohydrate Energy Reserves, Dry Matter Yields, and Herbage Quality of Tall Fescue

“…Other studies have found that tall fescue has lower herbage quality compared to species such as perennial ryegrass and prairie grass (Callow et al, 2003;Sinclair et al, 2006). Th e lower digestibility of tall fescue is largely due to the lower proportion of cell content and lower cell wall digestibility than other species such as perennial ryegrass (Wilman et al, 1996). Th e current results emphasize the dichotomy of this species, with relatively frequent defoliation at the two-leaf stage required to maintain an ME concentration above 10.3 MJ kg −1 DM, contrasting with relatively infrequent defoliation at the four-leaf stage required to maximize pasture production and persistence.…”

Effect of herbage mass and allowance on sward characteristics, milk production, intake and rumen volatile fatty acid concentration

“…The digestibility and chemical composition of a ryegrass plant is mainly influenced by its stage of growth (Wilman et al. , 1996).…”

Effect of Spring Grazing Date and Stocking Rate on Sward Characteristics and Dairy Cow Production During Midlactation

“…Previous studies have highlighted the beneficial effects of defoliating pastures in early spring on sward quality during the main grazing season (O'Donovan et al, 2004). Herbage chemical composition is frequently influenced by the regrowth age (Wilman et al, 1996), seasonal accumulations of dead herbage (L'Huillier, 1987), and increases in sward leaf proportion. The lategrazed swards supported a greater HM >4.0 cm than the early-grazed swards in R2 (+1,055 kg of DM/ha).…”