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