Effects of nitrogen fertilization and dried distillers grains plus solubles supplementation on long-term performance of growing beef steers grazing smooth bromegrass

Authors: HODGES, MORGAN - University Of Nebraska; MCDERMOTT, REBECCA - University Of Nebraska; WATSON, ANDREA - University Of Nebraska; HEIL, HOLLY - University Of Nebraska; HANFORD, KATHY - University Of Nebraska; MACDONALD, JIM - University Of Nebraska; ERICKSON, GALEN - University Of Nebraska

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2025
Publication Date: 3/31/2026
Citation: Hodges, M., Mcdermott, R.L., Watson, A.K., Heil, H.A., Hanford, K., Macdonald, J.C., Erickson, G.E. 2026. Effects of nitrogen fertilization and dried distillers grains plus solubles supplementation on long-term performance of growing beef steers grazing smooth bromegrass. Applied Animal Science. 42:99-108. https://doi.org/10.15232/aas.2025-02720.
DOI: https://doi.org/10.15232/aas.2025-02720

Interpretive Summary: This 17-yr study evaluated whether cattle fed with dry distillers grains plus solubles (DDGS) can be stocked at the same rate as nonsupplemented cattle on nitrogen-fertilized smooth bromegrass pastures. Cattle supplemented with DDGS were also more resilient to changes in precipitation and temperature. Supplementation could serve as a risk management strategy that protects against the negative effects that adverse weather conditions can have on cattle performance. Additionally, fertilizing pastures with 90 kg of N/ha or supplementing cattle daily with DDGS increased body weight gain per hectare per steer and improved carrying capacity of smooth bromegrass pastures, as demonstrated by increased stocking rate per unit of land and greater residual biomass at the end of the grazing period. Our long-term study results indicated that supplementation of cattle with DDGS can increase land use efficiency for forage-based cattle production systems.

Technical Abstract: Objective: The objective of this experiment was to examine the long-term effects of distillers grain supplementation and nitrogen (N) fertilization on animal performance to determine whether cattle supplemented with dry distillers grains plus solubles (DDGS) can be stocked at the same rate as nonsupplemented cattle on N-fertilized smooth bromegrass pastures. Materials and Methods: Each year, 45 steer calves weighing 321 ± 27 kg were assigned to 1 of 3 treatments. Treatments consisted of (1) steers grazing nonfertilized smooth bromegrass pastures supplemented with DDGS at 0.6% of BW (DM basis; SUPP); (2) steers grazing smooth bromegrass pastures fertilized with 90 kg of N/ha (FERT); or (3) steers grazing unfertilized smooth bromegrass pastures without DDGS supplementation (CONT). Pasture was the experimental unit, with 3 replications per treatment each year, and pastures were rotationally grazed during the grazing season. The CONT treatment pastures were 30% larger than the SUPP and FERT pastures, based on previous research indicating that nonfertilized pastures produced ~70% as much forage as fertilized pastures. Results and Discussion: Across the 17 yr, cattle on the SUPP treatment had greater ADG (1.03 kg) than those on CONT (0.73 kg) and FERT treatments (0.73 kg), which were similar to one another. Similar ADG between the CONT and FERT demonstrate that forage availability was the same and appropriate pasture sizes were used. Body weight gain per hectare was greatest for the SUPP treatment (378 kg/ha), intermediate for the FERT treatment (271 kg/ha), and least for the CONT treatment (186 kg/ha). Implications and Applications: Pasture use efficiency is increased through DDGS supplementation or fertilization of pastures, with the SUPP treatment being the most productive per hectare. Responses vary across years due to precipitation and pasture performance.