Intake, digestibility of nutrients, daily weight gain, and feed conversion were evaluated in beef cattle receiving diets containing the following ratios of sorghum silage:Tifton 85 haylage: 0:100; 32:68; 66:34; and 100:0. Diets were formulated to be isonitrogenous (12% crude protein) with a forage:concentrate ratio of 60:40, on DM basis. Twenty-four crossbred Holstein x Zebu steers averaging 360 kg of initial body weight were distributed in a completely randomized block design with 15 days for diet adaptation followed by three experimental periods of 28 days each. Indigestible acid detergent fiber (IADF) was used to estimate fecal output. Mean daily intakes of DM, OM, CP, EE, TC, and TDN all were not affected by treatments with mean values of: 9.46, 9.05, 1.20, 0.52, 7.4, and 6.23 kg/day, respectively. Significant quadratic effects were observed for the apparent total tract digestibilities of DM, OM, CP, and EE with estimated minimum digestibilities of 60.33, 61.58, 61.89, and 55.83% for the levels of 44.80, 47.18, 50.95, and 51.21% of sorghum silage in the forage portion of the diet, respectively. Mean daily weight gain and feed conversion also were affected quadratically by increasing the level of sorghum silage in the forage portion of the diet with estimated maximum and minimum values of 1.25 kg/day and 7.66 for the levels of 60.95 and 67.04% of sorghum silage, respectively. Results indicated that varying dietary ratios of Tifton 85 haylage and sorghum silage is a good alternative for feeding forage to finishing beef cattle. Inclusion of approximately 60% of sorghum silage in the total dietary forage resulted in the greatest estimated weight gain.
carcass yield; feed conversion; feedlot; roughage
