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An experiment was conducted to evaluate the feed intake, nutrient digestibility and selected rumen parameters in feedlot bulls fed diets containing different feed additives. Six rumen-cannulated Nellore bulls (age = 8 ± 1.0 months; initial BW = 225 ± 13.2 kg) were distributed in a 6 × 6 Latin square design. Six experimental diets based on 30% corn silage and 70% concentrate on a dry matter (DM) basis were evaluated. Diets differed in feed additive on a DM basis, as follows: 1.4% bicarbonate and magnesium oxide in 3:1 ratio (BOX); 36 ppm lasalocid sodium (LAS); 30 ppm monensin sodium (MON); 25 ppm virginiamycin (VIR); 30 ppm monensin sodium plus 25 ppm virginiamycin (MV); and 3.15% commercial mineral supplement containing D-limonene and exogenous α-amylase (EOA). The experiment lasted 144 d, with six periods of 24 d. Each period consisted of 14 d for dietary adaptation, 3 d for feces and urine collection, and 7 d for omasal and ruminal digesta collection. Bulls fed the BOX diet showed greater (P < 0.05) intake of DM, organic matter (OM), neutral detergent fiber (apNDF), crude protein (CP), and starch compared to the other diets. Diets with LAS, MON, VIR, MV, or EOA did not influence (P > 0.05) the DM, OM, apNDF, CP, or starch intake of feedlot bulls. Bulls fed the EOA diet showed greater (trend; P = 0.09) ruminal digestibility of starch compared to the other diets. The feed additives did not affect (P > 0.05) the intestinal or total tract digestibility of starch, rumen pH, microbial efficiency, total rumen fluid, dilution rate, rate of intake, rate of degradation, or passage rate of the DM, OM, apNDF, and starch. In conclusion, LAS, MON, VIR, MV, and EOA diets reduced nutrient intake compared to BOX. Although all feed additives presented similar effects on rumen pH, temperature, and kinetics the presence of exogenous α-amylase in the EOA diet may increase ruminal starch digestibility and apparent total tract digestibility of DM and OM.

This study aimed to evaluate ruminal in situ degradation of diets containing different levels of dried distillers grains (DDG) replacing soybean meal, urea and corn and the effect of these diets on in situ ruminal degradation of DDG, and to propose alternative methods to estimate in vivo digestibility of diets. Four rumen-cannulated Nellore bulls were used in a 4 × 4 Latin square design, for both in situ incubation and in vivo digestibility. We evaluated the following treatments: diet without DDG (D0) or containing 150 (D150), 300 (D300), or 450 g/kg (D450) of inclusion. For in situ evaluation, DDG was incubated in all animals, and diets only in those fed with the same diet that would be incubated. To estimate in vivo digestibility, three days of total feces collection were performed in each period. Data was analysed in PROC MIXED, PROC NLIN and PROC REG of SAS (version 9.4, SAS Institute Inc., Cary, NC, USA). There was no effect of diet on the in situ degradation parameters of the DDG (P > 0.05). However, for the diets, the readily soluble fraction (parameter "a") (P

This study aims to (1) verify the influence of flint corn processing methods on intake; rumen digestion kinetics; microbial efficiency; rumen pH; and ruminal, intestinal, and total tract digestibilities in Nellore bulls; and (2) determine whether snaplage (SNAP) plus a mineral–protein supplement could be used successfully to supply energy, fiber, and protein in a finishing diet without causing ruminal acidosis. Five rumen-cannulated Nellore bulls (265 ± 18.2 kg, 8 ± 1.0 mo old) were distributed in a 5 × 5 Latin square design. Five different diets were evaluated. Three experimental diets [dry matter (DM) basis] comprised 600 g/kg dry ground corn grain (DCG), high–moisture corn (HMC), or reconstituted corn grain silage (RCG) plus 300 g/kg whole-plant corn silage and 100 g/kg mineral–protein supplement. SNAP was included in two experimental diets, namely 900 g/kg SNAP (SNAP-90) or 800 g/kg SNAP +100 g/kg stalklage (SNAP-80) plus 100 g/kg mineral–protein supplement. The experiment lasted 115 d, with five periods of 23 d. These periods were divided into two subperiods of 14 d for dietary adaptation and 9 d for ruminal emptying, omasal, urinary, and fecal sample collection. Statistical analyses were performed using the MIXED procedure in SAS 9.4. DCG-based diet tended (P = 0.07) to increase DM and organic matter (OM) intake. Diets based on HMC, RCG, SNAP-80, and SNAP-90 increased (P