The effects ofdiet adaptation protocol by steers and of feeding four dietary urea levels (0,0.65, 1.3, and 1.95%, dry matter - DM basis) on intake and total apparent digestibilityof DM, organic matter (OM), crude protein (CP), ether extract (EE), total carbohydrates(CHO), neutral detergent fiber (NDF), nonfiber carbohydrates (NFC) and totaldigestible nutrients intake (TDN) for Holstein, ½ Holstein-Guzera, ½Holstein-Gir and Zebu steers were evaluated in this trial. The animals wereassigned to four 4x4 latin squares (genetic groups): four animals, four experimentalperiods and four treatments (diets). The animals were fed diets (12% CP, withincreasing urea levels) with 50% tifton-85 bermudagrass hay and concentrate.The first experimental period lasted 19 days, 13 days for adaptation and 6 daysfor feces collection. The possibility of reducing diet adaptation in the subsequentperiods was investigated by evaluating daily DM intake in the adaptation period.The indigestible acid detergent fiber (FDAi) was used as marker of fecal drymatter flow. The adaptation to diets of the subsequent experimental periodswas reduced by 10 days, because DM intake means, for each urea level, from 1stto 12th day of adaptation did not differ from the standard mean (13thday). The intake, expressed as kg/day, was higher for Holstein animals, followedby the crossbreds and Zebu. Total DM digestibility was affected nor by the geneticgroups, neither by the dietary urea levels.
