156. Performance of Steers Grazing Summer Cover Crops with and Without Nitrogen Fertilization

Abstract The objective of this study was to determine if utilizing cover crops with or without N fertilization would improve steer performance compared to volunteer annual grasses. Treatments were applied to pastures in a 2 × 2 factorial arrangement, with factors of forage type (cover crop versus volunteer grass) and N fertilizer (no fertilizer versus 54.43 kg N/ha), resulting in four treatments: Volunteer (volunteer annual grasses with no fertilization), Volunteer+Fert (volunteer annual grasses with N fertilization), CC (cover crops without fertilization), and CC+Fert (cover crops with N fertilization). The cover crop seed mix contained 11 kg/ha of brown midrib sorghum sudan, 16 kg/ha of sunn hemp, 11 kg/ha of mung bean, 22 kg/ha of cowpea, and 5 kg/ha of okra and was planted using no-till methods in pastures (4.1 ± 1.08 ha) previously planted with winter wheat. Steers (n = 40; initial BW = 336 ± 50.3 kg) grazed pastures for 56 days (June 19th to August 14th, 2025). The initial tester steers were initially stocked at 0.8 ha/steer and additional steers (grazers) were added every two weeks as forage grew, achieving a forage allowance of 3.5 kg DM/kg BW. Unshrunk BW was measured on consecutive days at the start and end of the grazing period to calculate initial and final BW, and an interim full weight was measured on d 28. Grazing days per ha was calculated as the number of testers times the full 56 days of grazing, added to the number of grazers times their corresponding number of grazing days following each respective reallocation, and divided by pasture size. Total BW gain per ha was calculated as grazing days per ha multiplied by average tester ADG per pasture. Data were analyzed using the GLM procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) with the fixed effects of forage, fertilizer, and the interaction using pasture as the experimental unit. No interactions were observed between forage type and N fertilization (P > 0.029). Initial and final BW were similar among treatments (P > 0.19). Grazing days per ha were increased by about 55% for Volunteer and Volunteer+Fert (P < 0.05). However, CC and CC+Fert increased ADG (P < 0.01) by 70%, which resulted in those treatments also producing greater total BW gain per steer (P < 0.01), with CC producing almost double the total BW gain per steer compared to Volunteer. Total BW gain per ha was not influenced by forage type, but did increase by 27% with fertilization (P < 0.01). Overall, the cover crop mixture resulted in improved steer BW gains due to improved ADG, while utilization of N fertilizer in both cover crops and volunteer annual grasses resulted in increased steer performance on a per ha basis.