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An experiment was conducted to evaluate impacts of RAMP (Cargill Corn Milling, Blair, NE) on methane (CH4) and carbon dioxide (CO2) emissions, performance, and carcass characteristics of beef cattle during the grain adaptation phase and finishing phase. Crossbred steers [n = 64; initial body weight (BW) = 347 ±7 kg] were utilized in two treatments; RAMP, fed 100% RAMP during step one and then stepped up to a common finisher diet consisting of 65.5% steam-flaked corn (SFC), 22.5% Sweet Bran (SB), 8% wheat straw, and 4% supplement. The second treatment was control (CON) fed 30.5% SFC, 22.5% SB, 8% wheat straw 35% alfalfa hay, and 4% supplement during step one and then stepped up to the common finisher diet. There were 8 steers per pen and 4 paired replications. Replications were stepped up together and rotated through a twochamber emissions barn in 5-day cycles to measure CH4 and CO2 emissions at three time points: step one of step-up phase, early feeding phase (one week after starting the finishing diet), and later finishing phase (13 weeks after starting the finishing diet). Performance data were analyzed using the MIXED procedure of SAS with treatment and BW block as fixed effects and emissions data analyzed with BW block and treatment as fixed effects and barn chamber as a covariate. Feeding RAMP during step one of the step-up phase led to a decrease in CH4, as g/d (P = 0.03) and a decrease in the CH4:CO2 ratio (P = 0.02). However, CH4 as g/kg of dry matter intake (DMI) was not affected by treatment (P = 0.25). Control steers had a decrease in CO2 as g/day (P = 0.03), but not as CO2 g/kg of DMI (P = 0.31). There were no differences in DMI (P = 1.00) during the step-up phase, averaging 10.3 kg/d for both treatments. For measures taken while all cattle were on the common finishing diet, RAMP did not reduce CH4, as g/d or g/kg DMI (P = 0.27), CO2 as g/d or g/kg DMI (P = 0.37), or CH4:CO2 (P = 0.12). There were no significant differences in DMI (P = 0.49) whole cattle were in the emissions barn during the feeding phase. There were no significant differences for interim (d 66) cattle performance including BW (mean 504 kg; P = 0.84), DMI (mean 9.7 kg; P = 0.27), ADG (mean 2.33 kg/d; P = 0.88), or G: F (mean 0.246; P = 0.30). Feeding RAMP to cattle during the grain adaptation phase resulted in a 12% decrease in methane emissions on a g per day basis without affecting cattle performance. This reduction in emissions didn't carry over into the finishing phase when a common diet was fed. [ABSTRACT FROM AUTHOR]

A metabolism experiment was conducted to evaluate the effects of daily feeding of encapsulated Megasphaera elsdenii (M. elsdenii) NCIMB 41125 along with a one-time dose of Lactipro NXT (MS Biotec) on dry matter intake (DMI), rumen pH, in vitro lactate disappearance, volatile fatty acid (VFA) concentration, and lactate concentration. Ruminally cannulated crossbred steers (n = 40, initial BW 437 ± 98 kg) were individually fed a finisher diet consisting of 70% steam-flaked corn, 18% modified distillers grain plus soluble, and 7% alfalfa hay. Treatments were control (Con) steers which were given no M. elsdenii and four treatments that received LactiproNXT on day 1 and were given 0 (Drench), 1×106 (Low), 1×107 (Medium), or 1×108 (High) CFU of encapsulated M. elsdenii daily throughout the experiment fed as a top-dress. Adaptation to the finishing diet was accomplished in 19 days for Con steers and 9 days for steers in the Drench, Low, Medium, and High treatments. The experiment included five continuous periods: step-up (d 1-19); finishing (d 20-88); feed restriction (d 89, 24-h full feed restriction); challenge (d 90, cattle were fed at 150% of max DMI from finishing period); and recovery (d 91-94). Data were analyzed using the MIXED procedure of SAS with linear and quadratic effects of dose with drench as the intercept. There were no significant differences for DMI in the step-up, finishing, or challenge period. In the recovery period, DMI was greater for Low, Med, and High compared with Drench (P = 0.07) and there was a tendency for a linear increase in DMI with increasing the dose of M. elsdenii (P = 0.11). Recovery period DMI, expressed as a percentage of pre-challenge intake, was greater (P = 0.05) in steers fed M. elsdenii daily compared with Drench steers, and increased linearly (P = 0.06) as dose of M. elsdenii increased. Rumen pH in steers fed M. elsdenii daily was greater (P < 0.01) during the feeding period and tended to be greater during the challenge (P = 0.14) and recovery (P = 0.11) periods when compared with the Drench treatment. In vitro lactate disappearance tended to be greater (P = 0.13) in steers given M. elsdenii daily when compared with Con and Drench on d 88. For days 90, 91, and 92 combined, a treatment effect was observed for in vitro lactate disappearance with steers in the Low, Med, and High treatments having greater (P < 0.05) disappearance than Con steers, and Med steers having greater (P < 0.05) disappearance than all other treatments. An accelerated step up is possible with the drench and daily feeding of M. elsdenii. Daily feeding of M. elsdenii has a positive effect on cattle during and after an acidosis challenge event. [ABSTRACT FROM AUTHOR]