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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 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]

The effect of a nutritional-packet was evaluated on time spent ruminating, eating, and chewing (ruminating + eating) by intensively managed beef steers consuming a finishing diet during the final 65 d of feeding prior to slaughter. Furthermore, the influence of behavior on CH4 production was determined. Twentyfour Angus-crossbreed steers were distributed into pens with SmartFeed (C-Lock) technology in which they were treated with: control or nutritional-packet [0.29% DM basis; live yeast (8.7 Log CFU/g); Vitamin C (5.4 g/kg); Vitamin B1 (13.33 g/kg); NaCl (80 g/kg); KCl (80 g/kg)]. An ear tag containing multiple accelerometers (CowManager) was placed on steers, and such device continuously recorded rumination and eating time (min/day). Enteric CH4 emissions were measured for 15 d using the SF6 tracer technique. Feeding behavior data were analyzed as a randomized complete block design using the MIXED procedure of SAS. The model included the fixed effect of treatment and the random effect of block. Steer was considered experimental unit. The GLM procedure of SAS was used for regressing behavior and CH4 production data. There were no differences between treatments for time (within 24 h) spent ruminating, eating, or chewing (P = 0.197). When nutrient intake was taken into account, no differences (P = 0.139) were observed between treatments for time spent ruminating, eating, and chewing per kg of dry matter, organic matter, neutral detergent fiber intake, and acid detergent fiber intakes. The production of CH4 was not affected by time spent ruminating (0.93 g/min; R2 = 0.0003; P = 0.935), eating (3.34 g/min; R2 = 0.03; P = 0.409), or chewing (0.69 g/min; R2 = 0.006; P = 0.728). The feeding behavior of intensively managed beef steers during the final 65-d of feeding was not driven by the nutritional-packet supplied, neither was CH4 production associated with feeding behavior variables measured. [ABSTRACT FROM AUTHOR]

The effects of a nutritional packet on performance and carcass characteristics of feedlot beef steers were evaluated. Thirty Angus-crossbred steers (BW = 542 ± 8.4 kg) were used in a randomized complete block design and allocated into pens with SmartFeed (C-Lock; 15 steers/treatment). Steers were consuming a steamflaked corn-based finishing-diet, ad libitum, for the last 65-d on feed prior to slaughter, in which treatments were: 1) control and 2) a nutritional-packet [0.29% DM basis; 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); KCl (80 g/kg)]. Individual BW was recorded every 14 d and carcass quality data was collected at slaughter. Steer was considered the experimental unit. The MIXED procedure of SAS was used with the fixed effect of treatment and the random effect of block. Total DMI was unaffected (P = 0.610) by treatment from d 0-65; however, control steers had greater (P = 0.030) DMI from d 54-65. The G:F was unaffected (P = 0.830) by treatment from d 0-35; however, it was greater (P ≤ 0.001) for steers fed the nutritional packet from d 0-50, and 0-65. Treatment did not affect (P = 0.920) ADG from d 0-35, however it increased (P ≤ 0.001) ADG from d 0-50 and tended (P = 0.060) to increase ADG from d 0-65. Carcass adjusted final BW tended (P = 0.060) to increase by 28% for treated cattle, whereas the Longissimus dorsi area tended to decrease (P = 0.090). No differences (P = 0.240) were observed for fat thickness, while yield-grade (P = 0.03) increased for treated cattle. The nutritional packet appears to improve performance in the final days of feeding steers under intensive management, and energy partitioning may be altered to fat deposition. [ABSTRACT FROM AUTHOR]

A randomized complete block design was used to evaluate the effects of bismuth subsalicylate (BSS) on in vitro ruminal fermentation with differing concentrations of sulfate. In vitro fermentation consisted of 50 mL of a 4:1 buffer:ruminal fluid inoculum and 0.7 g (pre-dehydrated) of substrate [WW-B Dahl bluestem hay (Bothriochloa bladhii)] incubated for 48 h (39oC). Treatments were arranged as a 3 × 4 factorial with concentration of sulfate (0.2, 2.9, or 5.6 g sulfate/L buffer) and BSS (0.0, 0.165, 0.330, or 0.495% substrate DM) as the main factors. In vitro organic matter digestibility (IVOMD), and CH4, H2S, and total gas production (TGP) were measured. Data were analyzed using the MIXED procedure of SAS with the fixed effects of BSS, sulfate, and their interaction. Incubation day (block) was considered a random effect. The average of 2 bottles within day was considered experimental unit. A BSS × sulfate interaction was observed for TGP (P = 0.040) and H2S production (P < 0.001), where BSS had a larger negative impact on TGP and production of H2S with greater concentrations of sulfate. A linear effect (P < 0.001) of sulfate was observed for CH4 production per gram of incubated OM, where CH4 was decreased as sulfate concentration increased. A quadratic effect of sulfate was observed for IVOMD (P = 0.010) and pH (P = 0.009). Production of H2S linearly decreased (P = 0.001) as BSS concentration increased. The addition of BSS to in vitro incubations did not affect (P > 0.10) any other variables measured. Bismuth subsalicylate does not appear to have negative effects on in vitro fermentation parameters while decreasing H2S production; however, elevated concentrations of sulfate in the buffer appears to have negative impacts on fermentation. Further in vivo research is warranted to support BSS supplementation to cattle with high dietary sulfate. [ABSTRACT FROM AUTHOR]

A replicated 3 × 3 Latin square was used to determine the effects of bismuth subsalicylate on ruminal fermentation parameters of beef cattle consuming a feedlot diet. Six ruminally-cannulated Angus-crossbred steers (n = 3; 573 ± 105 kg BW) and heifers (n = 3; 553 ± 77 kg BW) were assigned 1 of 3 treatments: 1) low sulfur (S = 0.27% diet DM; LSUL); 2) high sulfur (S = 0.38% diet DM; HSUL); and 3) HSUL + 0.33% bismuth subsalicylate in diet DM; (BSS). Cattle were adapted to treatments for 14 d followed by 7 d of collections. Ruminal gas cap samples were collected at 0, 4, 8, and 12 h post-feeding on d 14, and ruminal fluid samples were collected on d 15 every 3 h post-feeding for 24 h. Data were analyzed using the MIXED procedure of SAS. Treatment tended (P = 0.099) to affect H2S concentration where BSS and LSUL were 50 and 61% lesser when compared to HSUL, respectively. A tendency (P = 0.061) was also observed for concentration of NH3-N where HSUL and BSS were lesser than CTRL. There was also a tendency for a treatment effect (P = 0.082) where HSUL had a lower pH than LSUL with BSS being intermediate. Furthermore, treatment tended (P = 0.0712) to affect the concentration of acetate where HSUL was lesser than BSS. No effect of treatment (P ≥ 0.124) was observed on total VFA concentration nor concentrations of butyrate, propionate, or valerate (P ≥ 0.138). Treatment tended (P = 0.084) to affect branched chain VFA concentration where BSS decreased concentrations compared to LSUL. Molar proportions of the major VFA were not impacted by treatment (P ≥ 0.100). In conclusion, BSS appears to decrease H2S production in the rumen without having negative effects on the fermentation profile. [ABSTRACT FROM AUTHOR]

The effects of a nutritional packet were evaluated on CH4 emissions and apparent total tract nutrient digestibility of feedlot beef steers. Thirty Angus-crossbred steers (BW = 542 ± 8.4 kg) were used in a randomized complete block design and allocated into pens equipped with SmartFeed (C-Lock; 15 steers/treatment). Steers were consuming a steam-flaked corn-based diet (88% concentrate DM basis) ad libitum for the last 65 d on feed, and received the following treatments: 1) control and 2) a nutritional packet [0.29% DM basis; 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); KCl (80 g/kg)]. Methane emissions and apparent total tract nutrient digestibility were measured during 3 periods with 5-d of collections each. Gas emissions from steers were measured utilizing the SF6 tracer technique. Feed and fecal samples were collected once and twice (0700 h and 1600 h) daily, respectively, to determine digestibility of nutrients using iNDF as an internal marker. Steer was considered the experimental unit. Data were analyzed as repeated measures using the MIXED procedure of SAS with the fixed effects of treatment, period, and their interaction, and the random effect of block. No treatment × period interactions (P ≥ 0.125) were observed for DMI and any of the CH4 production variables (g/day, g/kg BW0.75, g/nutrient intake, and g/nutrient digested). Moreover, treatments did not affect digestibility of DM, OM, or ADF (P ≥ 0.300); however, digestibility of NDF was increased for treated cattle (P = 0.013), which resulted in a tendency (P = 0.098) to decrease CH4 production in g per kg NDF intake and decreased (P = 0.020) grams CH4 per kg NDF digested. The nutritional packet may be altering ruminal fermentation on intensively managed steers and improving fiber digestibility, which can have benefits on CH4 emission intensity. [ABSTRACT FROM AUTHOR]