Evaluation of RAMP Instead of Forage during Grain Adaptation and Different Sorghum Varieties on Enteric Methane Production from Cattle

Authors

Jack T. Fort, University of Nebraska-LincolnFollow

First Advisor

Galen E. Erickson

Committee Members

Jim MacDonald, Jessica Sperber, Keara O'Reilly

Date of this Version

12-2025

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Animal Science

Under the supervision of Professor Galen E. Erickson

Lincoln. Nebraska, December 2025

Comments

Copyright 2025, Jack T. Fort. Used by permission

Abstract

Two experiments were conducted to evaluate the use of RAMP (Cargill Corn Milling, Blair, Nebraska) compared with traditional forage-based adaptations on methane (CH₄) and carbon dioxide (CO₂) emissions, performance, and carcass characteristics. Experiment 1, 64 yearling British × Continental steers (initial BW = 423 ± 6 kg) were adapted using 100% RAMP (RAMP) or a traditional forage diet (CON; 43% forage) before transitioning 22 d to a common finishing diet containing 65.6% steam-flaked corn. Emissions were measured in paired replications using a two-chamber indirect calorimetry barn. During adaptation RAMP did not affect CH₄ production (g/d; P = 0.66), CH₄:CO₂ (P = 0.71), CO₂ (P = 0.92), or DMI (P = 0.77). However, on the common finishing diet, RAMP-adapted steers tended to produce 8% less CH₄ (g/d; P = 0.10) and reduced CH₄:CO₂ (P = 0.03). RAMP steers had lighter HCW (450 vs. 456 kg; P = 0.06) and tendencies for reduced ADG (P = 0.06) and G:F (P = 0.11).

Experiment 2 utilized 64 similar steers (initial BW = 517 ± 0.9 kg) adapted with RAMP or forage to diets containing 51% or 71% steam-flaked corn. During adaptation, CH₄ (g/d) did not differ (P = 0.37), although CH₄:CO₂ was reduced for RAMP (P = 0.05). No differences occurred in CO₂ (P = 0.18) or DMI (P = 0.26). During the finishing period, CH₄ (g/d; g/kg DMI) and CH₄:CO₂ did not differ between treatments (P ≥ 0.25). RAMP-adapted steers had lighter HCW (462 vs. 467 kg; P = 0.02) and reduced final BW (P = 0.02).

A 169-d finishing experiment evaluated five dry-rolled sorghum grain varieties (X54346, AG1203, SP68M57, G38, and 341X120) compared with a dry-rolled corn control using indirect calorimetry. CH₄ g/kg DMI did not differ among varieties, although variety 5 produced 22% less CH₄ (g/d) than variety 2. CH₄:CO₂ ratios were similar, but variety 4 was numerically lowest. Feeding sorghum for the first 100 d increased DMI (P = 0.02) without affecting ADG or G:F (P ≥ 0.25).

Advisor: Galen E. Erickson