In vitro gas production including methane from bermudagrasses supplemented with dried distillers grains with solubles *

Abstract

Objective: The objective of this study was to document the simulated effect of dried distillers grains with solubles (DDGS) supplementation of Coastal bermudagrass (COS; Cynodon dactylon [L.] Pers.) and Tifton 85 bermudagrass (TIF; C. dactylon [L.] Pers. × Cynodon nlemfuënsis Vanderyst) forage on in vitro gas production, in vitro true digestibility (IVTD), in vitro NDF digestibility (IVNDFD), and methane production. Materials and Methods: Forage and DDGS were combined to represent 3 levels of supplemental DDGS (0, 0.25, or 1% BW), which resulted in ratios of forage:DDGS of 100:0, 87.5:12.5, and 50:50. Samples were incubated using the in vitro gas production technique, and headspace was sampled for quantification of methane concentration. The residue was rinsed in neutral detergent solution for determination of IVTD and IVNDFD. Results and Discussion: Discrete lag times of both the exponential and logistic equations decreased linearly (P < 0.01) with an increasing proportion of DDGS across TIF and COS. The IVTD of TIF (78% DM) was greater (P < 0.01) than for COS (71% DM), as was IVNDFD (66 vs. 54% NDF). Similarly, IVTD increased (P < 0.01) by 5% with 87.5:12.5 and by 19% with 50:50 across both COS and TIF. Methane production (g/kg of digestible DM and g/kg of digestible OM) decreased linearly (P ≤ 0.02) with an increasing proportion of DDGS for both COS and TIF. Implications and Applications: Results indicated that DDGS might be supplemented to cattle for increased diet digestibility with an additional potential benefit of reduced methane production. Efficacy of DDGS was dependent on forage nutritive value.