Submitted to: Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 19, 2009
Publication Date: January 26, 2009
Citation: Brink, G.E., Casler, M.D. 2009. Performance Characteristics of Common Temperate Grasses [abstract]. Midwest Forage Association Wisconsin Symposium and Annual Meeting. Technical Abstract: Seasonal changes in productivity and nutritive value of cool-season grasses influences pasture management and ration balancing decisions by the producer. Grass sward structure also influences intake by grazing animals. We determined seasonal yield and quality changes in the leaf and stem fraction of 10 temperate perennial grasses, and the distribution of dry matter and quality within canopies of those grasses at two Wisconsin locations. After reaching 6 in. height in the spring, summer, and fall, Kentucky bluegrass, ryegrass, orchardgrass, timothy, tall fescue (conventional and soft-leaf), meadow fescue, smooth bromegrass, reed canarygrass, and quackgrass were harvested to a 4 in. stubble every 5 days to 30 days maturity. In addition, after reaching 10 in height, swards were harvested by layers: 4 to 6, 6 to 8, and 8 to 10 in. Low-quality stems were produced more rapidly during the spring at the northern location than at the southern location for most species. When typically grazed in the spring (15-20 days maturity), Kentucky bluegrass and smooth bromegrass were the most productive at both locations (mean of 1500 lb leaf and 800 lb stem DM/acre at approximately 8 and 12 in. height, respectively). Perennial ryegrass was the least productive at both locations (mean of 800 lb DM/acre), but produced little or no stem fraction. Conventional and soft-leaf tall fescue were the most productive grasses in the summer and fall. Leaf protein of all grasses except Kentucky bluegrass and tall fescue remained above 20% up to 20 days maturity in all seasons, a level considered adequate for lactating dairy cows. Neutral detergent fiber digestibility (NDFD) of all grasses was greatest in the spring (mean of 70%) and lowest in summer (mean of 60%) at both locations. Greatest NDFD was measured in the spring in ryegrass and in the fall in meadow fescue. Grasses that grow most vigorously during the spring, such as timothy, smooth bromegrass, and quackgrass, produced more yield in the upper and middle portions of the canopy than orchardgrass, perennial ryegrass, and meadow fescue, while the opposite occurred in the summer. Forage quality of reed canarygrass, smooth bromegrass, and tall fescue declined from the top to the bottom of the canopy, but was similar throughout the canopy in perennial ryegrass, timothy, and meadow fescue. The results suggest that timing of grazing is most critical for Kentucky bluegrass, reed canarygrass, smooth bromegrass, and tall fescue, particularly in spring and summer, due to rapid declines in digestibility with maturity. Depending on the season, grasses require different management to maximize utilization, and that forage quality differences between canopy layers permits more complete utilization of some grasses than others without forcing the animal to consume poorer quality forage.