Effects of displacing modified distillers grains with dry-rolled corn in a totally mixed ration on performance of growing beef steers consuming cornstalk residue from different harvest methods

Abstract

Objective

The objective was to determine the effects of displacing modified distillers grains with dry-rolled corn in a TMR for steers consuming corn residue from 2 baling methods on growth of beef steers.

Materials and Methods

Crossbred beef steers (n = 120; initial BW = 281; SD = 15 kg) were assigned in a randomized complete block design with a 4 × 3 factorial treatment arrangement (10 steer/treatment). Factors included proportion of modified distillers grains with solubles (MDGS) and dry-rolled corn (DRC; 100:0, 80:20, 60:40, and 40:60 respectively) in the concentrate, and 3 forages; either high quality (70% brome hay and 30% sorghum silage; HQ) or corn residue from 2 baling methods. Corn residue was baled as a conventional rake and bale system (RB), or by disengaging the spreader on the combine and baling the tailings (DS). Steers were fed diets as a TMR (60:40 roughage:concentrate) individually for 84 d making steer the experimental unit.

Results and Discussion

A significant interaction was observed for DMI. At each proportion of MDGS in the concentrate, DMI for HQ (8.7, 9.2, 9.4, 8.5 kg/d) was greater than for RB (6.0, 5.5, 5.2, 5.6 kg/d) and DS (5.5, 5.0, 5.5, and 4.8 kg/d), which were not different. The interaction was due to the magnitude of the difference between intakes at the 40% MDGS level. Steers fed HQ had greater ending BW (393 kg) and ADG (1.31 kg/d) than those in RB (350 kg; 0.81 kg/d) and DS (346 kg; 0.76 kg/d). The G:F was not different for HQ, RB, and DS (0.148, 0.146, 0.149, respectively). As MDGS:DRC ratio decreased, ending BW (369, 365, 362, 356 kg), ADG (1.03,0.98, 0.96, 0.87 kg/d), and G:F (0.153, 0.153, 0.145, 0.139) decreased linearly.

Implications and Applications

Disengaging the spreader on the combine could result in similar animal performance as raking and baling for producers feeding crop residues. Decreasing the ratio of MDGS to DRC fed to growing steers fed a forage-based TMR reduced ending BW and ADG suggesting the energy supplied by MDGS cannot be replaced with DRC.