Effects of Planting Date and Forage Allowance on Steer Growth Performance and Grain Yield in a Dual-Purpose Winter Wheat System1

Two planting dates (early: September 4 and 5; late: September 25 and 26) for dual-purpose winter wheat in 16 cleantilled pastures, along with 162 crossbred steers (initial BW = 236 ± 6 kg) were used in a completely randomized design during the 2002 to 2003 winter wheat season. Steers were stratified by initial BW and randomly allotted to 4 initial stocking rates within each planting date. Average forage allowances ranged from 217 to 980 kg of DM/100 kg of BW for early-planted wheat, and 162 to 709 kg of DM/100 kg of BW for late-planted wheat. Early planting provided 24 more grazing days than late planting (120 vs. 96 d). Average daily gain, overall steer gain, and grain yield all responded in a quadratic (P ≤ 0.06) manner, peaking around a forage allowance of 700 kg DM/100 kg BW. All cattle performance measures were greater (P ≤ 0.01) for early- than late-planted wheat. Daily gains of steers grazing early-planted wheat ranged from 1.02 to 1.21 kg, compared with 0.81 to 0.98 kg for late-planted wheat. Gains per hectare also responded in a quadratic (P ≤ 0.02) manner, peaking at the least forage allowance and decreasing as forage allowance increased. Grain yields were greater (P ≤ 0.01) for late-planted wheat (2,771 to 3,921 kg/ha) compared with early-planted wheat (2,367 to 3,027 kg/ha). These data indicated that under excellent conditions, cattle performance can be substantially improved by early planting. However, in a dual-purpose winter wheat system, this advantage is partially offset by a subsequent reduction in grain yield.