The objective of this trial was to study intake, apparent total tract digestibility, and production of Nellore steers fed diets containing the following ratios of Brachiaria brizantha and sorghum silages: 100:0, 67:33, 33:67, and 0:100 on dry matter (DM) basis. Twenty-four castrated steers averaging 380 kg at the beginning of the trial and receiving a forage:concentrate ratio of 60:40 (DM basis) were used in a randomized complete block design (six replicates per treatment). The experiment lasted 78 days with three 21-days periods and 15 days for diet adaptation. The average intakes of DM, organic matter (OM), crude protein (CP), ether extract (EE), non-fiber carbohydrates (NFC), and total digestible nutrients (TDN) as well as passage rate all increased linearly with the increment of sorghum silage in the diet. Similarly, average body weight gain increased 0.00313 kg per unit of sorghum silage included in the diet. Apparent total tract digestibilities of DM, OM, CP, and neutral detergent fiber (NDF) also increased linearly when sorghum silage replaced Brachiaria brizantha silage in the diet whereas those of EE and NFC did not change significantly averaging 80.1 and 89.5%, respectively. It can be concluded that a Brachiaria brizantha:sorghum silages ratio of 67:33 can be fed to Nellore steers because it resulted in similar intake and body weight gain compared to the diet containing only sorghum silage.
indigestible acid detergent fiber; feedlot; production
