Ribeiro et al., 2001. Rev. Bras. Zootec., 30 (2): 573-580

The intake, total apparent digestibility and ruminal and intestinal apparent digestibilities of diets containing tifton 85 bermudagrass hays (Cynodon spp.) at different regrowth ages were evaluated with cattle. Four rumen and abomasum fistulated steers were allotted in a 4x4 Latin square. All diets consisted in 0 to 40 forage to concentrate ratio. The forage was consisted in Tifton 85 bermudagrass hay of 28, 35, 42 and 56 days of age, and the concentrate contained corn meal and mineral mix. The intakes of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDT) total carbohydrates (CHOS), total digestible nutrients (TDN), digestible organic matter (DOM) and total digestible carbohydrates (TDC) were affected by the hay age in the diet, with maximum estimated values of 5.81; 5.51; 0.71; 3.4; 4.69; 4.17; 4.04 and 3.5 kg/day, respectively, at the ages of 40.6; 40.6; 32.6; 41.5; 42.2; 37.6; 37.7 and 39 days. The apparent digestibilities of NDF and total CHOS decreased 0.33 and 0.21 percent units for each day of hay age, ranged from 68.5 to 59.1 and 76.9 to 71.1%, respectively. The digestibilities of DM, OM, CP and EE were not affected by the hay age, and presented mean values of 70.9; 72.6; 60.0 and 74.4%, respectively. The ruminal and intestinal nutrient digestibilities were not affected by the hay age in the diet.