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This study evaluated two roughage types (sugarcane and corn silage) and two concentrate feed levels (0 and 25% of the total dry matter) in the cattle diet, in a 2x2 factorial design, and compared passage rate measurements (indicator and rumen evacuation). Four Holstein-Zebu heifers cannulated in the rumen and ileum were evaluated, in a 4x4 Latin square design. Stool samples (8th - 10th day) and rumen fluid (8th day) were collected and the rumen was emptied (14th and 16th day). Treatments were compared by contrast, evaluating the effects of roughage, concentrate feed and interaction between these factors. Dry matter (DM) intake and neutral detergent fiber corrected for ash and protein (apNDF) were highest for animals fed corn silage, and DM and organic matter (OM) intake were highest when fed concentrate. There was no roughage effect on ruminal mass, but concentrate decreased ruminal NDF in the total digesta mass. The coefficients of total digestion of crude protein (CP), apNDF and non-fiber carbohydrates (NFC) were higher for sugarcane than corn silage. Concentrate feed improved the total digestibility of OM and NFC. Passage rates evaluated by the marker technique and rumen evacuation were similar. Corn silage or 25% concentrate in the cattle diet improved consumption, intake rate and nutrient digestibility. The particle passage rate can be estimated by rumen evacuation or by adjusting a nonlinear mathematical model.
