Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/1998
Publication Date: N/A
Interpretive Summary: Previous research has clearly demonstrated that Tifton 85 is higher yielding and more nutritious than Coastal bermudagrass. Tifton 85 also has higher fiber (cell wall) concentrations than Coastal. Three sequential experiments were conducted to directly compare the yield and forage quality of these important hybrid bermudagrasses. Plot harvested material ranging in age from 3- to 8-week and 2- to 7-week was evaluated for chemical composition and digestibility. Individually penned steers were fed 3-, 5-, or 7-week old Coastal or Tifton 85 hay to determine intake and digestion. All experiments confirmed the superiority of Tifton 85 in yield and nutritional value. In spite of consistently greater fiber concentrations, Tifton 85 was voluntarily consumed in amounts equal to Coastal. Digestibility of dry matter and all fiber fractions measured was always greater for Tifton 85. Increasing maturity increased fiber concentration and decreased digestibility to a similar extent with both bermudagrasses. In areas where both of these bermudagrasses is adapted, Tifton 85 can be expected to produce higher yields of more nutritious forage than Coastal.
Technical Abstract: A study was undertaken to determine effects of bermudagrass cultivar and maturity on DM and digestible DM yield in vitro and in situ digestion, cell wall composition, and intake and digestion by steers. In Exp.1, Tifton 85 bermudagrass (T85) and Coastal bermudagrass (CBG) were harvested at 3-8 wk. Tifton 85 bermudagrass had a 7.1% greater DM yield, 18.2% higher (P<.05) digestible DM yield and 7.1% greater (P<.05) IVDMD than CBG. IVDMD decreased (P<.05) after 5 wk. In Exp.2, T85 and CBG were harvested at 2-7 wk. Although T85 had higher concentrations of NDF and ADF than CBG, T85 had 34.1% higher DM yield, 47.9% higher digestible DM yield, greater P<.05) IVDMD, in vitro NDF and ADF disappearances and higher (P<.05) in situ DM and NDF digestion. Coastal had higher lignin concentrations and lower (P<.05) total neutral sugars, arabinose, glucose and xylose concentrations than T85. Digestibilities of DM, NDF and ADF in vitro decreased while concentrations of ADF and lignin increased after 5 wk. In Exp.3, T85 and CBG forages were harvested as hay at 3, 5, or 7 wk and fed ad libitum to 36 individually penned steers (initial BW = 243.8 kg). Although T85 had greater concentrations of NDF, ADF, hemicellulose and cellulose than CBG, steers fed T85 had higher (P<.05) digestion of DM, OM, NDF, ADF, hemicellulose and cellulose than steers fed CBG. T85 was higher yielding and more digestible in vitro, in situ and in vivo than CBG.