Evaluation of Dried and Wet Distillers Grains Included at Two Concentrations in the Diets of Lactating Dairy Cows
Abstract
The purpose of this study was to determine the lactation performance of dairy cows fed dried or wet distillers grains (DG) with solubles (DOGS or WDGS) at two dietary concentrations. Using 15 cows, a lactation trial was designed as a replicated 5 x 5 Latin square. Periods were 4 wk each, with samples and data collection during wk 3 and 4. Diets, on a OM basis, were: control (C), 10% DOGS, 20% DOGS, 10% WDGS, and 20% WDGS. All diets contained 25% corn silage, 25% hay, and 50% of the respective concentrate mixes. Diets were balanced, using corn and soybean meal, for 17% crude protein. Dry matter intake (DMI) tended (P < 0. 1) to be greater for cows fed C than 0G (23.4, 22.8, 22.5, 23.0, 21.9 kg/d for C, 10% DOGS, 20% DOGS, 10% WOGS, 20% WOGS). Milk yield (39.8, 40.9, 42.5, 42.5, 43.5 kg/d) was greater (P < 0.05) for cows fed DG than C. Milk fat percentage (3.23, 3.16, 3.28, 3.55, 3.40) was similar for cows fed C and DG, but greater (P < 0.05) for cows fed WDGS than DOGS. Milk fat yield (1.28, 1.32, 1.39, 1.44, 1.43 kg/d) was greater (P < 0.05) for cows fed DG than C, and tended (P < 0.1) to be greater for cows fed WDGS than DOGS. Milk protein percentage (3.05, 3.01, 3.02, 3.11, and 3.06) was similar for cows fed C and DG, but greater (P < 0.05) for cows fed WDGS than DOGS. Milk protein yield (1.20, 1.22, 1.29, 1.29, 1.33 kg/d) was greater (P < 0.05) for cows fed DG than C, tended (P < 0.1) to be greater for cows fed WDGS than DOGS, and tended (P < 0.1) to be greater for cows fed 20% DG than 10% DG. Milk urea nitrogen (13.3, 12.6, 12.4, 12.9, 14.l mg/dL) was similar for cows fed C and DG, but greater (P < 0.05) for cows fed WDGS than DOGS, and tended (P < 0.1) to be higher for cows fed 200/o DG than I 00/o DG. Ruminal ammonia (NH3) concentrations (4.81, 3.75, 3.10, 3.91, 5.04 mg/dL) were greater (P < 0.05) for cows fed WDGS than DOGS. Overall, feeding DG improved performance by decreasing DMI, and increasing yields of milk, protein, and fat. This led to greater (P < 0.05) feed efficiency, as determined by energy-corrected milk (ECM) divided by DMI, in the DG fed cows compare to C fed cows (I. 70, 1. 79, 1.87, 1.84, 1.92 ). Responses were simi tar for 10% or 20% DG; however, feeding WDGS instead of DOGS increased milk fat and protein percentages. A supplemental in situ study showed that SBM had a greater (P < 0.05) ruminal degradability of OM and CP compared to DG, WDGS had a higher degradability of NDF and CP than compared to DOGS.
Key words: Distillers grains, Dairy cows