Seasonal Changes in Yield, Digestibility, and Crude Protein of Vegetative and Floral Tillers of Two Grasses

Abstract

The seasonal change of dry matter (DM) yield, estimated in vivo dry matter digestibility (DMD), and crude protein content of the vegetative and floral tillers of 'Rosana' western wheatgrass (Agropyron smithii) and 'Lodorm' green needlegrass (Stipa viridula) was determined on forage harvested April through October on 10 dates during 1973 and on 11 dates during 1974. Vegetative tillers on both grasses were comparable in seasonal DM yield, DMD, and crude protein for both years. Flora tillers of western wheatgrass produced only 20% as much forage as did floral tillers of green needlegrass; however, they contained on the average 2 and 4 percentage units more crude protein and DMD, respectively, than floral tillers of green needlegrass. On an average, floral tillers contained 4 and 8 percentage units less crude protein and DMD, respectively, than companion vegetative tillers. When floral tillers are harvested before DMD decreases below 50%, they are most valuable for maintenance of mature animals. Preventing development of floral tillers would increase DMD but decrease DM yield.