In the southern United States, bermudagrass (Cynodon dactylon) is the predominantly used warm season forage. Eastern gamagrass (Tripsacum dactyloides L.) is being evaluated as an alternative to bermudagrass. The objective of this study was to determine intake and digestibility of bermudagrass or eastern gamagrass hay supplemented with increasing levels of dried distillers grains with solubles (DDGS) by sheep. In Experiment 1 (Exp. 1), bermudagrass hay (BG) was supplemented with 0, 10, 20, and 30% DDGS, and in Experiment 2 (Exp. 2), eastern gamagrass hay (EG) was also supplemented with the same levels of DDGS. In each experiment, a total of 4 crossbred wether sheep (Katahdin × Dorper; one year old, 33.2 ± 1.7 kg, BW) were used. The sheep were individually housed in pens and randomly assigned to each of the 4 diets. Each treatment consisted of 4 periods of 14 d/period (10 d adjustment and 4 d sample collection). Animals received hay ad libitum after the supplement was completely consumed. At the end of each period, a 7-mL blood sample was collected from each animal and analyzed for PUN, glucose, and NEFA concentrations and rumen fluid samples were also collected and analyzed for ruminal ammonia nitrogen (NH₃-N) and volatile fatty acids (VFA) concentrations. Nutrient digestibility was estimated using the total fecal (bag) collection method. Data from each experiment were analyzed as a separate Latin square design using SAS. DDGS supplementation did not (P > 0.05) affect BG hay DMI but increased (P < 0.05) EG hay DMI. In both experiments, DM, OM, ash, NDF and ADF digestibilities were not affected (P > 0.05) but CP and EE digestibilities increased (P < 0.05) with DDGS supplementation. Although DDGS supplementation did not affect total VFA concentrations in Exp. 1, it tended (P = 0.09) to decrease in Exp. 2. Plasma urea nitrogen (PUN) concentrations increased with DDGS supplementation in both experiments. Plasma glucose, NEFA, or rumen NH3-N, pH concentrations were not affected (P > 0.05) by DDGS in both experiments.