The purpose of the study was to determine fermentation and degradability of eight sorghum cultivars, being 8050-Agromen, 8118-Pioneer, 8419-Pioneer, BR306, BR700, BRS305, BRS701, Saara-Monsanto at different stages of growth, and to determine effects of condensed tannins (CT) in sorghum grain using a bio-assay. Cultivars were planted in 5 m×4.5 m plots in a randomized block design. Whole plants were harvested 30, 60, 90 and 120 days post-sowing, but grains (cobs) were harvested only at 120 days from plants other than those harvested as whole plant. Samples were analyzed for ash, acid detergent fibre and crude protein. In vitro gas production determinations of whole plant samples and grains were completed on oven dried (40 °C for 48 h) samples ground to pass a 1 mm screen. Grain samples assayed for CT, and their interference in gas production, was determined with addition of polyethylene glycol. Differences (P
