Effects of adding urea on fermentation quality ofpruned persimmon branch silage and its digestibility,preference, nitrogen balance and rumen fermentationin beef cattle

摘要

Four cattle were used in a 4 × 4 Latin square design experiment to study digestibility, ruminal fermentation, nitrogenretention and preference of ensiling pruned persimmon branch (PPB) chips treated with urea. After 60 days of ensiling,urea-treated PPB showed higher (P < 0.05) pH, acetic acid and ammonia-N levels than no-urea PPB. Both urea-treated PPBand rice straw diets showed higher (P < 0.05) apparent digestibility and digestible nutrient content in cattle than no-ureaPPB diet. Neither mold nor yeast was detected in any urea-treated PPB. Urinary and fecal excretion as well as nitrogenretention in cattle fed urea-treated PPB were higher (P < 0.05) than in those fed no-urea PPB and rice straw. With theexception that ruminal ammonia-N levels in cattle fed urea-treated PPB were higher (P < 0.05) than in those given no-ureaPPB and rice straw, ruminal pH, volatile fatty acid concentrations, and the acetic : propionic acid ratio of rumen contentwere unaffected by diets. The rank order of preference was rice straw > low-urea > no-urea > high-urea. The resultssuggested that urea treatment of PPB inhibited growth of mold and yeast during silage storage, enhanced its digestibilityand had nutritive value almost equivalent to that of rice straw.