Effects of Fat Content and Type on the Value of Distillers Grains Plus Solubles for Finishing Cattle

Abstract Distillers grains plus solubles (DGS) is commonly fed to growing and finishing cattle, where it provides both energy and protein. Historically valued as a protein source due to limited quantities, DGS gained prominence in the early 2000s with the expansion of the ethanol industry, shifting its use towards displacing dietary energy, primarily from corn, in feedlot diets. Distillers grains from the traditional process contained 30-33% protein, 33-36% neutral detergent fiber and 12-13% fat. Beginning in 2012, ethanol plants began extracting a portion of oil during processing, reducing its fat content to 8-9%. An analysis was conducted to determine the feeding value of full-fat and de-oiled DGS relative to a corn control and to quantify the impacts on dry matter intake (DMI) and average daily gain (ADG). This dataset included 50 experiments with over 6,100 head of finishing cattle conducted at the University of Nebraska from 1993 to 2023. This analysis was limited to experiments that displaced dry-rolled corn, high-moisture corn or a combination of the two, and containing 15% or more DGS. Data were analyzed using the MIXED procedure of SAS with distillers type (dried, modified, or wet DGS), fat content (full fat or de-oiled), and the interaction between DGS type and fat content included in the model. Distillers grains type had a significant impact on the percentage change in DMI compared to the corn control (P 0.01), whereas fat content had no effect (P = 0.13). Feeding dried and modified DGS increased DMI by 6.0 and 3.4%, respectively, relative to the control. There was a tendency for an interaction between DGS type and fat content for improvements in ADG (P = 0.09). Feeding full-fat dried and wet DGS resulted in a greater improvement in ADG compared to their de-oiled form. However, for modified DGS the de-oiled form had a greater improvement in ADG compared to its full-fat form, which could be due to a greater increase in DMI when fed in the de-oiled form. Regardless of DGS type or fat content, feeding DGS improved ADG by 8% compared to the corn control. Both DGS type and fat content significantly influenced feeding value (P ≤ 0.03). For dried, modified, and wet DGS, the feeding value was 113.4%, 119.5%, and 129.3% when fed in the full-fat form and 103.4%, 114.7%, and 120.4% when fed in the de-oiled form. On average, partial fat removal, lowered the feeding value of DGS by 8 percentage units from 120.7% to 112.8% across all DGS types. Despite this reduction in the feeding value, de-oiled DGS increased ADG relative to the corn control. The improvement in feeding value for wet and modified DGS illustrates that feeding DGS provides both protein and energy for finishing cattle.