A balanced forage program should include species that provide the highest yields of quality forage throughout the grazing period. In the Northeast, where cool‐season grasses predominate, the short supply of forage during summer limits beef cow‐calf herd size. Warm‐season (C4) perennial grasses are productive in midsummer and may supplement temperate species for grazing and hay. ‘NY 1145’ big bluestem (Andropogon gerardi Vitman) and ‘Blackwell’ switchgrass (Panicum virgatum L.) were grown on soils (Aeric Fragiaquualt and Aquic Hapludalf) low in available P at two locations in Pennsylvania to characterize changes in quality of leaf and stem tissue associated with maturation. Forage was harvested at 10‐day intervals beginning at the 3‐ to 4‐leaf stage in late June and continuing until seed set in early August. Percentage leaf tissue declined similarly with maturation for the two grasses. Leaf dry matter yields were approximately twice those of stems in June but the opposite was true in August. At early head emergence, percentage leaf tissue for big bluestem and switchgrass averaged 34 and 44%, respectively. Averaged over grasses, leaf and stem forage quality estimates at early head emergence, respectively, were: crude protein (CP), 9.7, 4.3% in vitro dry matter disappearance (IVDMD), 60.4, 50.0%; neutral detergent fiber (NDF), 66.0, 75.3%; lignin, 4.7, 7.2%; and phosphorus (P), 0.20, 0.16%. Big bluestem leaves were higher in CP but lower in NDF than switchgrass leaves. Stem tissue of big bluestem was lower in NDF but higher in lignin than that of switchgrass. The decline in leaf and stem CP, IVDMD, and P with maturation was less pronounced in leaf tissue. The increase in NDF and lignin with maturity was greater in stems than in leaves. Fiber accumulation in stem tissue continued after seedheads emerged and was accompanied by decreases in CP and IVDMD. At early vegetative stages, the high percentage of good quality leaf tissue suggest the potential use of big bluestem and switchgrass for ruminants with above maintenance energy requirements. However, at later growth stages (late joint early head), the increase in stem tissue and associated decline in nutritive value suggest using these grasses either for grazing or hay by ruminants to meet only maintenance energy needs.

Feeding trials were conducted with 428 forages in three forage classes (C3 grasses, legumes, C4 grasses) fed ad libitum to sheep and with 170 forages fed to cattle over a 20-yr period. Of this total, 153 forages were fed concurrently to sheep and cattle. Where the same forages were fed, mean dry matter digestibility (DMD) and dry matter intake (DMI) were lower (P less than .01) for sheep than for cattle, with significant effects of forage class. With the main population of forages, the regression of DMI on DMD was positive and curvilinear (P less than .01) for sheep, with no effect of forage class, and positive and linear (P less than .0001) for cattle, with a significant effect of class. For all forages, correlations between DMI and neutral detergent fiber (NDF) concentration were -.57 for sheep and -.41 for cattle; regressions differed (P less than .05) with class and animal species. Correlations of DMD with NDF and acid detergent fiber (ADF) concentrations were -.45 and -.59 (P less than .01), respectively, for sheep, and -.32 and -.39 (P less than .01) for cattle; again, regressions differed significantly with class and animal species. Within forage class, regressions of DMD and DMI on fiber components generally were linear. Intake of NDF (NDFI) was related to NDF percentage for all forages by a quadratic regression, with significant differences due to animal species and forage class. Results indicate that relationships between DMD, DMI and fiber fractions differ between forage classes and animal species, that C4 grasses are consumed at levels higher than would be expected from their DMD and fiber concentrations and that ruminants increase NDFI in response to higher NDF concentrations in the forage.

‘Grasslands Puna’ chicory (Cichorium intybus L.) is a perennial taprooted herb that shows potential to produce high yields of palatable forage for ruminants. Our objective was to determine management effects on herbage production and quality, and stand persistence. Chicory and ‘Pennlate’ orchardgrass (Dactylis glomerata L.) were established on Hagerstown silt loam (fine, mixed, mesic Typic Hapludalf) soil at Rock Springs, PA. Treatments were intensive, moderate, and lenient management, corresponding to 25‐, 37‐, and 50‐cm chicory canopy height at harvest, with N fertilizer applied after each harvest except the last. The experimental design was a 2 × 3 (species × managements) factorial with five replications. Total yields of forage averaged 9A Mg ha−1 for chicory and 7.9 Mg ha−1 for orchardgrass in 1992 and 1993. Management did not affect total yield of chicory the first harvest year, nor that of orchardgrass in either year. Chicory yield was greatest from plants under lenient management the second year. Mean crude protein concentration in chicory and orchardgrass was 200 g kg−1 and 185 g kg −1 respectively, but both species showed a potential to accumulate concentrations greater than 250 g kg−1. Low concentrations (110 g kg−1) were associated with floral stem production. Chicory herbage had higher concentrations of Ca, Mg, Na, Fe, Cu, and Zn, than did orchardgrass. Our results show that Grasslands Puna can withstand a range of defoliation intensities while maintaining excellent productivity.

The isolation and analysis of cell‐wall types (CWT) such as parenchyma and sclerenchyma provide a means of understanding the complex chemistry of forage fiber. Our objective was to compare the composition of purenchyma and sclerenchyma cell walls of field grown orchard grass (Dactylis glomerata L.) and switch grass (Panicum virgatum L.) harvested at four stages of plant maturity. Leaf blades, leaf sheaths, and stems were analyzed for fiber constituents. Parenchyma and sclerenchyma cell walls were mechanically isolated from plant parts and analyzed for neutral sugars, alkali‐labile phenolic acids, and lignin. Neutral‐detergent fiber (NDF), hemicellulose, cellulose, and lignin concentrations differed (P < 0.05) between plant parts. Parenchyma cell walls differed widely in composition, with urabinose ranging from 25 to 81 g kg−1; xylose, 92 to 282 g kg−1; glucose, 410 to 634 g kg−1; p‐coumaric acid, 1 to 19 g kg−1; ferulic acid, 2 to 10 g kg−1; and lignin, 38 to 104 g kg−1. Sclerenchyma cell walls were more uniform in composition, with arabinose ranging from 10 to 30 g kg−1; xylose, 204 to 330 g kg−1; glucose, 411 to 533 g kg−l; p‐conmaric acid, 5 to 16 g kg−1; ferulic acid, 3 to 9 g kg−1; and lignin, 51 to 99 g kg−1. In most cases, the ratios of xylose to urabinose and p‐coumaric acid to ferulic acid were lower (P < 0.05) in purenchyma compared with sclerenchyma, and in leaf blade or leaf sheath CWT compared with those of the stem. These results suggest that the chemistry of CWT is complex and that studies of heterogenous preparations such as NDF are confounded by the chemical diversity of CWT contained in forages.