In situ rumen dry matter, neutral detergent fiber, and crude protein degradability in dairy cows and in vitro intestinal digestibility of dried distillers grains with solubles with varying fat concentrations

ABSTRACT Objective Our objective was to evaluate the effects of fat concentration on the rumen degradability and intestinal digestibility of dried corn distillers grains with solubles (DDGS) from different ethanol biorefineries that produce DDGS with varying fat concentrations. Materials and Methods Three rumen-cannulated primiparous Holstein cows were used to evaluate the in situ ruminal DM, alpha amylase–treated NDF, and CP degradability of DDGS. The 6 DDGS samples were placed in nylon bags with a 50 ± 10 μm pore size and incubated in the cows for 0, 2, 4, 8, 16, 24, 48, 72, and 120 h. The 16-h rumen residues were used in determination of in vitro intestinal and total digestible protein. Results and Discussion Fat concentration affected in situ rumen degradability and in vitro intestinal digestibility. High fat and low fat DDGS had 51.5 and 58.0% rumen degradable DM, respectively (P = 0.03). Intestinal digestible protein and total digestible protein were greater for low fat than high fat DDGS samples (67.6 vs. 54.6%; 85.8 vs. 77.1%, respectively). Implications and Applications Low fat DDGS were more rumen degradable and more intestinally digestible, which will affect the feeding value of DDGS. When feeding DDGS, determining the digestibility and understanding the biorefinery’s processing method will aide in understanding the nutritional value of DDGS.