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The effects of a nutritional packet containing a direct-fed microbial combined with vitamins/electrolytes offered to beef steers in a calf-fed system on apparent total tract nutrient digestibility were evaluated. Angus crossbred steer-calves (n = 60; BW = 234 ± 4 kg) were assigned to a randomized complete block design (block = body weight; steer = experimental unit) and stratified into 2 treatments: a) control (no packet, finely-ground corn carrier only); and b) 30 g of DM/animal-daily of a nutritional packet [liveyeast (Saccharomyces cerevisiae; 8.7 Log CFU/g), Vitamin C (5.4 g/kg of Ascorbic acid), Vitamin B1 (13.33 g/kg of Thiamine hydrochloride), and electrolytes of NaCl (80 g/kg) and KCl (80 g/kg)]. Animals were individually offered [electronic feed-bunks (Smart-Feed/C-Lock Inc.)] a steamflaked corn-based finishing diet ad libitum, once daily for 233 d. Treatments were offered during the first (phase-1) and last (phase-2) 60 d on feed. At the conclusion of each phase, feed samples were collected once daily (1400 h), while fecal samples twice daily (0700 and 1700 h) from each steer during 4 consecutive days. Fecal and feed sample composites were dehydrated (55oC), ground (1 mm), and analyzed to assess DM, OM, NDF, ADF, and hemicellulose. The 288-h indigestible NDF was used as dietary internal marker to estimate fecal output and used to calculate nutrient digestibility. Data were analyzed using the GLIMMIX procedure of SAS. Intake of DM, OM, and fiber components during both digestibility trials were not affected (P = 0.56) by treatments. Steers offered the nutritional packet had increased (P < 0.01) apparent total tract digestibility of DM, OM, NDF, ADF, and hemicellulose by at least 2.4, 2.4, 8.3, 10, and 7.5%, respectively, in both digestibility phases. Superior nutrient digestibility without affecting nutrient intake may justify a potential enhanced carcass energy deposition. [ABSTRACT FROM AUTHOR]

The effects of a nutritional packet containing a direct-fed microbial combined with vitamins/electrolytes offered at the beginning and end of the finishing phase to beef steers in a calf-fed system on feeding behavior were evaluated. Angus crossbred steer-calves (n = 18; BW = 234 ± 4 kg) were assigned to a randomized complete block design (block = body weight; steer = experimental unit) and stratified into two treatments: a) control (no packet, finely-ground corn carrier only); and b) 30 g of DM/animal-daily of a nutritional packet [live-yeast (Saccharomyces cerevisiae; 8.7 Log CFU/g), vitamin C (5.4 g/kg of ascorbic acid), vitamin B1 (13.33 g/kg of thiamine hydrochloride), and electrolytes of NaCl (80 g/kg) and KCl (80 g/kg)]. Animals were individually offered [electronic feed-bunks (Smart-Feed/C-Lock Inc.)] a steam-flaked corn-based finishing diet ad libitum once daily for 233 d, while treatments were offered during the first (phase-1) and last 60 d (phase-2) on feed only. Feeding behavior activities were assessed in min/d by using CowManagerTM ear tag sensors. Data were analyzed using the GLIMMIX procedure of SAS. There was no treatment × phase interactions (P ≥ 0.15), except that steers receiving the nutritional packet tended (P = 0.10) to spend more time (6 vs. 9 min/kg) eating digestible DM during phase-2 only. Regardless of phase, steers consuming the nutritional packet spent more time (P = 0.04) eating per kg of hemicellulose. Regardless of treatment, a decreased rumination (P ≤ 0.03) and chewing (P ≤ 0.01) activity-variables were observed for the phase-2 compared to phase-1. Steers receiving the nutritional packet exhibited superior time spent on eating activities, especially during the final 60 d before slaughter, and fiber seems to be the major driver inducing such effect. Towards the end of the finishing phase, cattle reduced rumination and chewing compared to the arrival phase. [ABSTRACT FROM AUTHOR]

The effects of a nutritional packet containing a direct-fed microbial combined with vitamins/electrolytes offered to beef steers in a calf-fed system on growth performance and carcass characteristics were evaluated. Angus crossbred steer-calves (n = 60; BW = 234 ± 4 kg) were assigned to a randomized complete block design (block = body weight; steer = experimental unit) and stratified into two treatments: a) control (no packet, finely-ground corn carrier only); and b) 30 g of DM/animal-daily of a nutritional packet [live-yeast (Saccharomyces cerevisiae; 8.7 Log CFU/g), Vitamin C (5.4 g/kg of Ascorbic acid), Vitamin B1 (13.33 g/kg of Thiamine hydrochloride), and electrolytes of sodium chloride (80 g/kg) and potassium chloride (80 g/kg)]. Animals were individually offered [electronic feed-bunks (Smart-Feed/C-Lock Inc.)] a steam-flaked corn-based finishing diet ad libitum, once daily for 233 d. Treatments were offered during the first (phase-1) and last (phase-2) 60 d on feed. Body weight measurements were taken every 30 d before feeding. Data were analyzed using the GLIMMIX procedure of SAS. Steers offered the nutritional packet had 14% less (P < 0.01) intake and 18% greater gain efficiency during the initial 30-d on feed, while such advantage did not (P = 0.26) persist when accounting for the initial 60 d for either variable. Overall intake (d0 to d233) was 6% greater (P = 0.02), while carcass-adjusted ADG (1.61 vs. 1.56), and carcass-adjusted gain efficiency (0.198 vs. 0.204) were unaffected (P = 0.44) compared with control, respectively. Dressing percent of steers offered the packet was 1 percentage-unit greater (P = 0.02), while other carcass variables were unaffected (P = 0.33). Calffed steers seem to benefit from such nutritional packet during the initial 30 d after feedlot arrival, while both superior intake and dressing percentage appears to last until cattle harvest. [ABSTRACT FROM AUTHOR]

The effects of dietary inclusion of live bacteria on feedlot beef cattle apparent total tract nutrient digestibility were evaluated. Crossbred-Angus yearling steers (n = 192; initial BW = 409 kg ± 8 kg) were blocked by body weight (BW) and randomly assigned into 48 pens (4 steers/pen; 16 pens/treatment) following a randomized complete block design. A steam-flaked corn-based fishing diet was offered ad libitum once daily containing the following treatments: 1) Control, in which no direct fed microbial (DFM) was offered (lactose as carrier only); 2 and 3) Probiotic mixtures at distinct concentrations [Mixture A and B, at 2g/animal-daily (lactose used as carrier)]. Orts DM were quantified (if any) daily and subtracted from total dietary DM offered to calculate DM intake. Fecal samples were collected twice daily (0700 and 1700 h) for 5 consecutive days (d 68 to 72) from at least 3 steers per pen, while feed samples were collected daily. Samples were composited within period, dehydrated (55°C), and ground (1mm) for further analyses. Total fecal output was estimated with a dietary internal marker (288-h indigestible NDF) and used to calculate nutrient digestibility. Data were analyzed using the GLIMMIX procedure of SAS and pen was considered the experimental unit. Intakes of DM, OM, NDF, and ADF during the digestibility assessment were not affected (P = 0.13) by treatments. Steers offered DFM mixture-A tended to increase digestibility of DM (P = 0.07; 79.3 vs. 77.1%), NDF (P = 0.10; 56.9 vs. 51.6%), and hemicellulose (P = 0.08; 59.4 vs. 53.9%) compared with control, while digestibility of ADF was not affected (P = 0.24) by treatment. The DFM mixture-A seemed to positively affect apparent digestibility of nutrients in steers consuming a steam-flaked corn-based finishing diet, in which improvements in the fiber fraction digestion seemed to be a meaningful contributor. [ABSTRACT FROM AUTHOR]

The effects of dietary inclusion of live bacteria mixtures on feedlot beef cattle feeding behavior were evaluated. Crossbred-Angus yearling steers (n = 192; initial BW = 409 kg ± 8 kg) were blocked by body weight (BW) and randomly assigned into 48 pens (4 steers/pen; 16 pens/treatment) following a randomized complete block design. A steam-flaked corn-based fishing diet was offered ad libitum once daily containing the following treatments: 1) Control, in which no direct fed microbial (DFM) was offered (lactose as carrier only); 2 and 3) Probiotic mixtures at distinct concentrations [Mixture A and B, at 2g/animal-daily (lactose used as carrier)]. Orts DM were quantified daily and subtracted from total dietary DM offered to calculate DM intake. Feeding behavior activities (continuous 24 h) were visually assessed (d 106 and 113) by trained personnel, where time spent on each activity was recorded every 5 min. Data were analyzed using the GLIMMIX procedures of SAS and pen was considered the experimental unit. No treatment × period interactions (P ≥ 0.21) were observed. Main feeding behavior variables consisting of time spent ruminating, chewing, eating, and drinking in minutes per day were not affected (P ≥ 0.17) by treatments, while steers in general ruminated, ate, chewed, and were more active (P ≤ 0.01) during the second behavioral assessment, regardless of treatments. Rates of intake in minutes per kg of DM, OM, fiber and digestible DM, OM, and fiber were not affected (P ≥ 0.12) by treatments; however more time spent (P < 0.01) ruminating, eating, and chewing in minutes per kg were observed on d113 compared to d106 regardless of treatments. Drinking time (min/d) and drinking rates (min/kg) were not affected (P ≥ 0.81) by period. The DFM mixtures did not negatively affect feeding behavior of yearling steers consuming steam-flaked corn-based finishing diets. [ABSTRACT FROM AUTHOR]

The effects of the dietary inclusion of live bacteria mixtures on feedlot beef cattle ruminal papillae morphology were evaluated. Crossbred-Angus yearling steers (n = 192; initial BW = 409 kg ± 8 kg) were blocked by body weight (BW) and randomly assigned into 48 pens (4 steers/pen; 16 pens/treatment) following a randomized complete block design. A steam-flaked corn-based fishing diet was offered ad libitum once daily during 153 d containing the following treatments: 1) Control, in which no direct-fed microbial (DFM) was offered (lactose as carrier only); 2 and 3) Probiotic mixtures at distinct concentrations [Mixture A and B, at 2g/animal-daily (lactose used as carrier)]. Upon harvest at a federally inspected slaughter facility, epithelium samples were collected from the cranial sac of the rumen, immersed in a 70% alcohol, and preserved under refrigeration (5°C). Ruminal tissue fragments were trimmed (1cm2), in which papillae were completely counted within the fragment, followed by the removal of 12 random individual papillae for further area measurement using electronic scanning (ImageJ). Data were analyzed using the GLIMMIX procedure of SAS and pen was considered the experimental unit with the fixed effect of treatment and the random effect of block. Regardless of treatments, average papillae area in cm2 (P = 0.39; control: 0.38, DFM mixture-A: 0.40, DFM mixture-B: 0.37), papillae number within fragment (P = 0.70; control: 47, DFM mixture-A: 52, DFM mixture-B: 49), absorptive surface area in cm2/fragment cm2 (P = 0.87; control: 37, DFM mixture-A: 39, DFM mixture-B: 38), and ruminal absorptive surface area (P = 0.74; control: 97%, DFM mixture-A: 97%, DFM mixture-B: 97%) were not affected compared with control. The addition of DFM mixtures did not seem to affect ruminal papillae physical aspect, although the long-term effects of dietary inclusion of live bacteria on ruminal morphology needs to be further evaluated. [ABSTRACT FROM AUTHOR]

The effects of a nutritional packet containing a direct-fed microbial combined with vitamins/electrolytes offered to beef steers in a calf-fed system on ruminal papillae morphology and volatile fatty acid (VFA) profile were evaluated. Angus crossbred steercalves (n = 60; BW = 234 ± 4 kg) were assigned to a randomized complete block design (block = body weight; steer = experimental unit) and stratified into two treatments: a) control (no packet, finely-ground corn carrier only); and b) 30 g of DM/animal-daily of a nutritional packet [live-yeast (Saccharomyces cerevisiae; 8.7 Log CFU/g), Vitamin C (5.4 g/kg of Ascorbic acid), Vitamin B1 (13.33 g/kg of Thiamine hydrochloride), and electrolytes of NaCl (80 g/kg) and KCl (80 g/kg)]. Animals were individually offered [electronic feed-bunks (Smart-Feed/C-Lock Inc.)] a steamflaked corn-based finishing diet ad libitum once daily for 233 d, while treatments were offered during the first and last 60 days on feed only. Upon harvest (federally inspected facility), individual samples of ruminal cranial sac epithelium and rumen content (quickly frozen) were collected. Preserved (70% alcohol at 5oC) ruminal tissue fragments were trimmed (1 cm2), in which papillae were counted, followed by a random removal of 12 individual papillae for further area measurement using electronic scanning (ImageJ). Data were analyzed using the GLIMMIX procedure of SAS. Steers offered to nutritional packet had a 30% increased (P = 0.02) average papillae area, which induced a tendency (P = 0.14) to improve ruminal absorptive surface area (89 vs. 93%), while not affecting ruminal papillae number (P = 0.39). Molar proportions of acetate, butyrate, and propionate were not affected (P ≥ 0.51) by treatments, while total VFA (mM) tended (P = 0.09) to increase by 8% for animals consuming the nutritional packet. The nutritional packet seemed to improve ruminal fermentation products while positively affecting ruminal papillae morphology. [ABSTRACT FROM AUTHOR]

The effects of dietary inclusion of live bacteria on feedlot beef cattle growth performance and carcass characteristics were evaluated. Crossbred-Angus yearling steers (n = 192; initial BW = 409 kg ± 8 kg) were blocked by body weight (BW) and randomly assigned into 48 pens (4 steers/pen; 16 pens/treatment) following a randomized complete block design. A steam-flaked corn-based fishing diet was offered ad libitum once daily containing the following treatments: 1) Control, in which no direct fed microbial (DFM) was offered (lactose as carrier only); 2 and 3) Probiotic mixtures at distinct concentrations [Mixture A and B, at 2g/animal-daily (lactose used as carrier)]. Orts DM were quantified daily and subtracted from total dietary DM offered to calculate DM intake. Two-day consecutive unshrunk BW were recorded before feeding on d 0, 30, 60, 90, 121, and 153 (prior to shipment to a federally inspected slaughter facility). Data were analyzed using the GLIMMIX procedure of SAS and pen was considered the experimental unit, in which F-test protected pre-planned contrasts comparing control versus DFM mixture-A and control versus DFM mixture-B were used. Steers offered mixture-A increased carcass-adjusted ADG (P = 0.03) by 6.7%, gain efficiency (P < 0.01) by 6%, tended to increase carcass-adjusted final BW (P = 0.07) by 15kg and hot carcass weight (P = 0.07) by 10kg. The overall (d 0 to end) DM intake (P = 0.36) was not affected by treatment; however, a subtle (1.2%) decrease (P < 0.01) during the initial 30 days for steers offered DFM mixture-B was observed. Carcass variables (dressing percentage, 12th rib fat, longissimus muscle area, marbling, yield grade, and liver scores) were not affected (P = 0.13) by treatments. Growth performance was improved with DFM mixture-A which seemed to positively affect carcass weight without inducing deleterious effects on other carcass characteristics. [ABSTRACT FROM AUTHOR]

Direct fed microbials (DFM) dietary mixture effects on beef cattle ruminal variables, intake, and apparent total tract digestibility were evaluated. Six ruminally cannulated beef steers (BW = 520 ± 30 kg) were used in a duplicated 3 × 3 Latin square design and offered a steam-flaked corn-based finishing diet ad libitum for three 28-d periods (21-d adaptation and 7-d collection). Treatments assigned were: 1) Control (no DFM mixture; lactose only); 2 and 3) DFM mixtures at distinct concentrations [Mixture A and B, at 2 g/animal-daily (lactose used as carrier)]. Ruminal pH and temperature were measured every 6 min (wireless probes). Ruminal samples were collected at 0, 2, 4, 8, 16, and 23 h post-feeding on d28. Feed and fecal samples (collected once and twice daily, respectively) were composited by period and analyzed. Fecal output was estimated with a dietary internal marker (288-h indigestible-NDF). Data were analyzed using the GLIMMIX procedure of SAS. No treatment × time interactions (P = 0.20) were observed. Steers offered mixture-A experienced 300 min/d less (P = 0.04) time under the ruminal pH 5.6, tended (P = 0.13) for a lesser area under the curve of ruminal pH 5.6, while showing a greater (P = 0.04) ruminal pH average (5.67 vs. 5.50), and tended (P = 0.06) for a lesser ruminal temperature (39.2 vs. 39.4°C) compared to control. The ruminal concentration of NH3-N was greater (P = 0.02) for mixture-A compared with control (10.78 vs. 4.35 mg/dL), while animals offered mixture-B tended (P = 0.07) to be greater (9.11 mg/dL) than control. Steers offered DFM mixture-A increased (P = 0.04) ADF digestibility compared with control (39.8 vs. 54.0%), while not affecting DM intake (P = 0.61). The DFM mixture-A induced a safer ruminal pH environment and encouraging fiber degradation and NH3-N release, while not affecting animal intake. [ABSTRACT FROM AUTHOR]

The effects of a nutritional packet fed to beef steers during the feedlot finishing phase (final 64 d) on feeding behavior were evaluated. Crossbred-Angus steers (n = 120; initial BW = 544 ± 52 kg) were assigned to 30 pens (4 steers/pen; 15 pens/treatment; pen = experimental unit) in a randomized complete block design. Steers were fed, ad libitum, a steam-flaked corn-based finishing diet and treatments were applied as follows: 1) control and 2) 30 g/steer-daily (DM-basis) of a nutritional packet (containing live yeast [Saccharomyces cerevisiae; 8.7 Log CFU/g], vitamin C [5.4 g/kg], vitamin B1 [13.33 g/kg], NaCl [80 g/kg], and KCl [80 g/kg]). The nutritional packet used ground corn as a carrier and was included at 1% of diet DM. Orts were subtracted from the total dietary DM offered to calculate DM intake. Feeding behavior activities were visually assessed by trained personnel twice (d 27 and d 63) for 24 h, when time spent on each activity was recorded every 5 min. Data were analyzed using the GLIMMIX procedure of SAS. Treatment × period interactions (P ≤ 0.03) were observed for eating time (min/d) and eating rates (min/kg of consumed DM, OM, fiber, and digestible DM, OM, and fiber), in which steers fed the nutritional packet spent less time in such activities on d 27 and more time during the assessment on d 63, compared with control. Regardless of period, steers fed the nutritional packet tended (P = 0.07) to spend less time chewing per kg of digestible ADF. Rumination (P ≥ 0.28), drinking (P ≥ 0.40), active (P ≥ 0.92), and resting (P ≥ 0.53) times were not affected by treatment. The nutritional packet affected eating behavior more intensively during the first 27 d of treatment, and digestible ADF seems to be the main feed-fraction inducing such effect. [ABSTRACT FROM AUTHOR]

The effects of a nutritional packet fed to beef steers during the final 64 d of the feedlot finishing phase on growth performance and carcass characteristics were evaluated. Crossbred-Angus steers (n = 120; initial BW = 544 ± 52 kg) were assigned to 30 pens (4 steers/pen; 15 pens/treatment) in a randomized complete block design where pen represented the experimental unit. A steam-flaked corn-based finishing diet was fed ad libitum, and treatments were applied as follows: 1) control and 2) 30 g/steer-daily (DM-basis) of the nutritional packet (containing live yeast [8.7 Log CFU of Saccharomyces cerevisiae], vitamin C [5.4 g/kg of Ascorbic acid], vitamin B1 [13.33 g/kg of Thiamine hydrochloride], sodium chloride [80 g/kg] and potassium chloride [80 g/kg]). The nutritional packet used ground corn as a carrier and was included at 1 % of diet DM. Orts were quantified daily (if any) and subtracted from the total dietary DM offered to calculate DM intake. Unshrunk BW were collected on d 0, 21, 42 and 64 before daily feeding at 0630 h. Data were analyzed using the GLIMMIX procedure of SAS. Average daily gain (P = 0.89), dry matter intake (P = 0.57) and, gain:feed (P = 0.66) were not affected by the inclusion of the nutritional packet. The 12th rib fat deposition was increased (P ≤ 0.02) for cattle fed the nutritional packet compared with control (15.70 vs. 13.36 mm, respectively). Consequently, calculated yield grade was also increased (P ≤ 0.03) for cattle consuming the nutritional packet (3.32 vs. 3.02). An improved carcass fatdeposition without any deleterious effects on growth performance potentially warrant less days on feed when cattle receive such nutritional packet. [ABSTRACT FROM AUTHOR]

The effects of a nutritional packet fed to beef steers during the final 64 d of the feedlot finishing phase on apparent total tract nutrient digestibility were evaluated. Angus-crossbred steers (n =120; initial BW = 544 ± 52 kg) were assigned to 30 pens (4 steers/pen; 15 pens/treatment; pen = experimental unit) in a randomized complete block design. A steam-flaked corn-based finishing diet was fed ad libitum and treatments applied as follows: 1) control and 2) 30 g/steerdaily (DM-basis) of the nutritional packet [containing live yeast (Saccharomyces cerevisiae; 8.7 Log CFU/g), vitamin C (5.4 g/kg), vitamin B1 (13.33 g/kg), NaCl (80 g/kg) and KCl (80 g/kg)]. The nutritional packet used ground corn as a carrier and was included at 1% of diet DM. Orts were quantified daily (if any) and subtracted from the total dietary DM offered to calculate DM intake. Fecal samples were collected twice daily (0700 and 1700 h) for 5 consecutive days (d 47 to 51) from at least 3 steers within pen. Feed samples were collected daily at time of feeding (0630 h). Fecal and feed samples were composited to represent the collection period, dried (55oC), ground (1 mm), and analyzed to assess DM, OM, NDF, ADF, and hemicellulose. In situ (288 h) iNDF was used as an internal marker to measure apparent total tract nutrient digestibility. Data were analyzed using the GLIMMIX procedure of SAS. Intake of DM, OM, and fiber components during the digestibility period was not affected (P ≥ 0.44) by treatment. Steers fed the nutritional packet had increased apparent total tract digestibility of OM (P = 0.02), DM (P = 0.01), NDF (P = 0.02), ADF (P = 0.01), and hemicellulose (P = 0.08; tendency). Improved nutrient digestibility without affecting nutrient intake may warrant an enhanced energy deposition in the carcass. [ABSTRACT FROM AUTHOR]

The effects of live yeast (Saccharomyces cerevisiae) and ruminal environment on in vitro true digestibility of dry matter, organic matter, and fiber components were evaluated. Ruminally-cannulated beef steers (n = 4; BW = 520 ± 30 kg) were used in a cross-over design to serve as donors of ruminal content. In vitro substrates (6 grower and 6 finisher diets) and individual ingredients (steam-flaked corn, wet corn gluten feed, and old-world bluestem hay) were dehydrated (55o C), ground (1 mm), and incubated using a 2 × 2 factorial arrangement of treatments: a) the presence or not of yeast (8×109 CFU/animal-daily adjusted to a 70 L ruminal content volume), and b) two ruminal inoculums collected from donors fed a grower (50:50) or a finisher (92:08) diet (concentrate:forage). Four incubation batches (experimental unit) were performed, in which the initial two batches were performed followed by another two after animals switched diets and were adapted again during 21d. A Daisy in vitro incubation system was used, and samples incubated for 48h (39°C). The GLIMMIX procedure of SAS was used for the statistical analysis. No 3-way interactions (P ≥ 0.71) or 2-way interactions with substrate were observed (P ≥ 0.25). The in vitro true digestibility of DM, OM, NDF, and hemicellulose increased when yeast was added to the incubator containing a 50:50 ruminal content (Rumen × Yeast; P ≤ 0.02). The ADF digestibility increased (P = 0.02) with yeast addition regardless of ruminal content type (50:50 or 92:08). As expected, finisher substrate diets were more (P < 0.01) digestible than grower diets. The combination of live yeast and a specific ruminal environment seemed to be more important than substrate type, in which live yeast improved in vitro digestion within a 50:50 ruminal inoculum more evidently. [ABSTRACT FROM AUTHOR]