The intake and the total and partial digestibility of nutrients, the microbial efficiency, the nitrogen balance, the passage rates of ruminal digesta, the pH and the ammonia ruminal concentration in beef cattle fed diets containing tifton 85 haylage and sorghum silage in the following proportions: 100:0; 68:32; 34:66 and 0:100, respectively in DM basis. Four crossed animals (H × Z) fistulated in the rumen and abomasum, with average body weight of 364 kg were assigned to a 4 × 4 Latin square. The forage: concentrate ratio was 60:40, in DM basis. The daily intake of DM, OM, CP, total carbohydrates (TC), as well as the total apparent digestibility of CP, EE, NFC and NDF were not influenced by the diets, with mean values of 6.01, 5.69, 0.76, and 4.64kg/day and 67.94, 82.12, 84.43, and 53.57%, respectively. The intake of EE, NFC, NDF and TDN and the total apparent digestibility of DM, OM and TC linearly increased with the increment of sorghum silage in the forage. The ruminal and intestinal digestibility of DM, TC, NFC and NDF were not influenced by the diets. The pH was not influenced by the collection time or by the diets. The ammonia concentration was influenced by the collection times, estimating the maximum value of 13.14 mg/100 mL, at 2.90 hour after feeding. Ruminal digesta passage rates of 4.10, 4.22, 4.27, and 5.30%/hour were respectively estimated for diets containing 0, 32, 66, and 100% of sorghum silage in the forage. The level of sorghum silage in the diet did not influence the microbial efficiency. The use of Tifton 85 haylage associated with sorghum silage has shown to be a great alternative of forage for finishing beef cattle.
ammonia; nitrogen balance; pH; passage rate
