TEMPORAL EFFECTS ON STEER PERFORMANCE AND NUTRITIVE VALUES FOR EASTERN GAMAGRASS GRAZED CONTINUOUSLY FOR DIFFERENT DURATIONS

Eastern gamagrass (Tripsacum dactyloides [L.] L.) has potential as a g razed forage, but options in its grazing management need to be evaluat ed. A 3-yr grazing study was conducted to determine temporal effects o n steer performance and nutritive values for eastern gamagrass that wa s continuously stocked for various durations. Pastures were stocked at different rates and grazed to targeted forage height of 30 to 38 cm t o impose treatments of 1) long duration of continuous stocking with a light stocking rate (3.0 steers/ha) 2) intermediate duration of grazin g with an intermediate stocking rate (4.9 steers/ha) or 3) short durat ion of grazing with a heavy stocking rate (SDHS; 7.4 steers/ha). Crude protein percentage and in vitro organic matter digestibility of leaf blade and sheath showed nonlinear declines (P < .05) as days on pastur e (DOP) increased. In vitro organic matter digestibility of leaf sheat hs was affected by two-way interactions (P < .05) between year and the Linear, quadratic, and cubic terms. Crude protein percentage of leaf sheaths was affected lay three-way interactions (P < .01) between dura tion of continuous stocking (DCS), year, and the Linear and quadratic terms. There were linear declines (P < .05) of cumulative average dail y gain as DOP increased, and the relationships did not differ (P) .10) among DCS or years. There was a quadratic (P < .05) relationship betw een cumulative live weight gain (kg/ha) and DOP, hut there also was an interaction (P < .001) between DCS and DOP on the Linear term. Cumula tive live weight gains (kg/ha) for SDHS showed the steepest increases as DOP increased. High live weight gain per unit of land area can be a chieved with eastern gamagrass, if grazed with high stocking rates to a targeted pasture height of 30 to 38 cm.