|Jackson, Randall -|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2010
Publication Date: February 19, 2010
Citation: Brink, G.E., Jackson, R.D. 2010. Tall, Short, Tall, Short – Which Way Should You Graze? [abstract]. Wisconsin Grazing Conference. p. 32. Technical Abstract: Grass pastures must reliably provide sufficient forage of appropriate quality to meet the intake and nutritional needs of livestock during the grazing season over a range of environmental conditions. This study is being conducted at the U.S. Dairy Forage Research Center farm at Prairie du Sac, WI. Meadow fescue, orchardgrass, quackgrass, and reed canarygrass were grazed with heifers throughout the season at either a vegetative (10-12” tall) or mature (stem elongation in spring or approximately 20 in. tall) stage to remove 50, 75, and 100% of the grass on a height basis. Yield and quality of forage consumed by cattle were measured each time grasses were grazed. Effects of management on tiller density, litter, and root growth were measured at the end of the season. When grass was grazed at a vegetative stage, increasing the amount of forage removed by the animal, or reducing the residual, increased the time to when the pasture was ready to be grazed again. Annual yield increased as residual was reduced, but when utilization reached 100% (no residual), the plant was sufficiently stressed that yield no longer increased, or decreased. At vegetative stage, extent of utilization had relatively little effect on forage quality. Grazing to a shorter residual, however, did have a negative impact on tiller density at the end of the season, which may be reflected in lower persistence next spring. When grass was grazed at a mature stage, residual did not greatly impact rotation time. Annual yield increased as residual decreased, and quality decreased, particularly in the spring and summer due because cattle grazed more stems. Tiller density was more negatively impacted as residual declined in quackgrass and reed canarygrass (rhizomatous grasses), than in meadow fescue and orchardgrass (bunch-type grasses), indicating that a minimum residual of 4 to 6 in. is necessary. Grazing at a mature stage reduced tiller density of all grasses compared to a vegetative stage.