LAUSR

An in vitro experiment was performed to evaluate the effect of quality and supplementation (CON-control, no supplement, DDG-dried distillers grains, 29.32% CP, LFD-liquid feed, 56.45% CP) on IVDMD, NDF disappearance (NDFD) and ruminal fermentation parameters of Tifton 85 Bermudagrass (Cynodon dactylon). Forage was harvested at 2, 4, 6, 8, and 10 wk over three growing seasons to simulate various forage management practices. Samples were analyzed by Near-infrared spectroscopy and stratified by relative forage quality (RFQ). Samples were selected to represent high (120), medium (100) and low (80) RFQ. The LFD was added at 5.4% of DMI, equivalent to 0.91 kg (as fed) per head per day. The DDG was included at equivalent of 16.99%, 14.36%, and 12.23% of total DM for the high, medium, and low low RFQ forages, respectively, to make the treatments isonitrogenous to the LFD treatments. Fermentations were carried out for 48 h on 3 d. The experiment was analyzed as a 3 x 3 factorial; arrangement with RFQ and type of supplement as factors. The IVDMD (46.9, 54.6, and 62.8%) and NDFD (41.7, 53.8, and 56.1%) increased (P < 0.001) as RFQ increased. Supplementation increased (P < 0.009) NDFD (39.7, 49.5, and 59.5%) but only the LFD increased IVDMD (52.7, 55.4 and 56.2%). An RFQ x supplement interaction was observed for IVDMD (P < 0.001) and NDFD (P < 0.007). No effects of supplementation were observed for high RFQ. For medium RFQ forage quality only LDF increased IVDMD and DDG was not different from CON or LDF; and no effect of supplementation was observed for NDFD. Supplementation increased IVDMD and NDFD for low RFQ forage. There was no effect of supplementation on total gas production or total VFA concentrations. Supplementation with LFD and DDG improves IVDMD and NDFD in low RFQ Bermudagrass, and LFD supplementation can enhance IVDMD in medium RFQ forage quality