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The objective of this study was to evaluate the effects of calcium magnesium carbonate (CMC) and/or tylosin phosphate (TYL) supplementation on behavior, rumination activity, growth performance and carcass characteristics of yearling beef steers. Treatments were arranged in a 2 × 2 factorial including CMC and TYL. Beef steers (n = 156; 469 ± 18 kg) were randomly assigned to treatment pens (7 to 8 steers/pen) with pen (n = 20 pens total, 10 pens/main effect mean, and 5 pens/simple effect mean) as experimental unit. Cattle were transitioned from a 30% roughage diet to a 7% roughage finishing diet based on dry-rolled corn, dried distillers grains plus solubles, liquid supplement, and oat silage over the initial 20 d period. The CMC was included at 1.5% of the diet (DM basis) in replacement of dryrolled corn and TYL was provided at 90 mg·animal·d-1. Behavior and rumination activity were monitored during a 24 h period on d 42. Data was collected on a pen-basis, every 10 min from 0800 h to 0750 h the next day and included minutes spent drinking (DR), eating (EA), active (AC), ruminating (RU), and resting (RE). Cattle were shipped for harvest on d 105 to a commercial beef abattoir. Growth performance was calculated on a carcass-adjusted basis (HCW/0.625). Data were analyzed as a randomized complete block design with fixed effects of CMC, TYL, or their interaction; block was a random effect. An interaction was observed between CMC and TYL for time spent DR (P = 0.03) and RU (P = 0.01). Control steers ruminated 28% longer compared with CMC/-TYL steers (P = 0.05) and 20% longer than -CMC/TYL steers (P = 0.05). The main effect of CMC tended to increase time spent EA by 19.3% (P = 0.06). Dry matter intake was decreased (P = 0.02) by 4.57% when CMC was fed and increased by 1.96% when TYL was fed. However, no difference (P = 0.26) was observed for G:F or gain efficiency in either treatment. No differences (P = 0.28) were observed in any dietary net energy utilization outcomes in either main effect treatment. Carcass weight tended (P = 0.07) to be lighter with CMC supplementation compared with CON (432 vs 439 kg). Supplementation of TYL resulted in a 11.7% reduction (P = 0.04) in percentage of abscessed livers. No differences (P = 0.12) were observed in DP, marbling, YG, or EBF in either main effect treatments. These results indicate that supplementation of CMC did not result in any appreciable improvements in growth, carcass or dietary net energy utilization performance, but TYL supplementation resulted in a positive effect on liver abscess prevalence. [ABSTRACT FROM AUTHOR]

The objective was to evaluate growth performance and carcass traits following transit of feedlot heifers sourced and finished in different geographical regions in the U.S. Yearling heifers [n = 190; initial body weight (BW) 483 and 425 kg for SD and TX sourced, respectively] were used in a 2×2 factorial arrangement of origin state (SD vs TX) and finishing state (SD vs TX). Heifers were allotted on d -1 into four treatments: sourced from SD and finished in SD (SD-SD), sourced from SD and finished in TX (SD-TX), sourced from TX and finished in SD (TX-SD), and sourced from TX and finished in TX (TX-TX). Heifers were weighed on d -1, 3, 15, 28, 56, 78 (TX-TX and SD-TX) and 90 (SDSD and TX-SD). On d 0, SD-TX and TX-SD heifers were shipped to the finishing location and weighed the following morning (d 1) to determine transportation shrink. To monitor transportation effects, vaginal temperature probes were inserted into all SD-TX and TX-SD heifers and a portion of SD-SD and TX-TX heifers on d -1 and removed on d 3. Clinical attitude scores (CAS) were recorded on d -1, 0, 1, 2 and 3 for indications of bovine respiratory disease symptoms. The GLIMMIX procedure of SAS was used to analyze growth performance and carcass measures with fixed effects of origin and finishing state. The MIXED procedure was used for CAS and temperature data with the same fixed effects and time as a repeated measure. Transported heifers had reduced temperatures (P < 0.05) during transit and post-transit compared with non-transported heifers. Temperatures of transported heifers increased (P < 0.05) during loading and unloading. On d 0, 1 and 3 there was a shift in the distribution of heifers that had a CAS score greater than 0 for TX-TX, SD-TX and TX-SD. Cattle endured high ambient temperatures (temperature humidity index value > 75) 54% and 18% of the feeding period for TX and SD finished heifers, respectively. All cumulative growth performance measures and carcass trait interactions were statistically significant (P < 0.05) besides initial BW, percent shrink of transported heifers, average daily gain, dressing percent, ribeye area and liver abscess severity, which were similar (P > 0.30). There was a shift in the distribution (P < 0.05) towards a greater proportion of Yield Grade 1 and Select carcasses for heifers fed in TX compared with those fed in SD, likely due to fewer days on feed. Overall, heifers transported to higher ambient temperatures had reduced dry matter intake, quality grades (QG) and limited growth recovery (45 kg lighter) compared with non-transported heifers. Heifers transported to lower ambient temperatures recovered growth and had improved QG at the same level of rib fat compared with non-transported heifers. [ABSTRACT FROM AUTHOR]

Charolais × Angus cross steers (n = 80; initial shrunk BW = 505 kg ± 31.6 kg; n = 10 pens; 5 replicate pens/treatment) were used in two 24-hour observations to evaluate animal behavior based on varying degrees of daily feed inclusion over a 28-day period (d 14 and d 42 on feed). Treatments included: 1) A fixed diet inclusion rate for each individual ingredient with a tolerance of 0.454 kg, and 2) Variable inclusion rates (VAR) of diet ingredients that were randomly increased or decreased while maintaining the targeted daily as-fed delivery. Steers were fed twice daily with a slick bunk approach used to manage feed bunks. Diets composition (DM basis) was 48% high moisture corn (HMC), 21% dry-rolled corn (DRC), 5% liquid supplement (LS), 14% dried distillers' grains plus solubles (DDGS), and 12% grass hay (GH). In the VAR treatment inclusions of HMC, DRC, and DDGS varied independently by assigning a random integer with each integer corresponding to a specific deviation from target. Dietary inclusion of LS was fixed. Inclusion of GH was altered so that the targeted as-fed amount was delivered each day. Inclusion rates of ingredients (HMC, DRC, and DDGS) on an as-fed basis varied from the formulated diet by -20, -15, -10, -5, 0, +5, +10, +15, or +20%. Data from the two 24-hour observations were analyzed using the GLIMMIX procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) with pen as the experiment unit. Treatment was analyzed as a fixed effect and block (pen location) was a random effect in the model. Varying ingredient inclusion did not affect cattle activity, time spent drinking, resting, eating, or ruminating, or chewing behaviors (P = 0.24) during the initial d 14 observation. Treatment did affect DMI the week preceding that observation period (P = 0.04). During the second 24-hour observation period activity, resting, ruminating, and chewing behaviors along with DMI were unaffected by variation in inclusion of diet ingredients (P = 0.33). Varying inclusion rates of diet ingredients increased time spent drinking (P = 0.05) by 33.3% and decreased time spent eating behaviors (P = 0.01) by 9.4% at the d 42 observation point. Under the conditions of the present experiment, altering dietary ingredient proportions in a finishing diet may influence time spent drinking and eating after 42 d on feed. [ABSTRACT FROM AUTHOR]

The objective of this research was to determine the influence manger space restriction had on program fed feedlot heifers during the growing phase. Charolais × Angus heifers [initial body weight (BW) = 329 ± 22.1 kg] were used in a 109-d backgrounding phase study. Heifers were received from a ranch in western South Dakota approximately 60 days before study initiation. Initial processing (53 days before study initiation) included individual BW measurement, application of a unique identification tag, vaccination against viral respiratory pathogens (Bovi-Shield Gold 5, Zoetis, Parsippany, NJ) and clostridial species (Ultrabac/Somubac 7, Zoetis), and administration of doramectin pour-on (Dectomax, Zoetis) for control of internal and external parasites. All heifers were administered 36 mg of zeranol (Ralgro, Merck Animal Health, Madison, NJ) at study initiation. Upon study initiation, heifers were assigned to 1 of 10 pens (n = 5 pens/treatment with 10 heifers/pen) in a randomized complete block design (blocked by location). Each pen was randomly assigned to 1 of 2 treatments: 20.3 cm (8IN) or 40.6 cm (16IN) of linear bunk space/heifer. Heifers were individually weighed on days 1, 14, 35, 63, 84 and 109. Heifers were programmed to gain 1.36 kg daily based on predictive equations for a medium frame steer calf set forth by the California Net Energy System. To calculate predictive values, a final BW of 575 kg was assumed to be the mature BW of the heifers and tabular net energy values of 2.05 NEm and 1.36 NEg from d 1 to 22, 2.00 NEm and 1.35 NEg from d 23 to 82, and 1.97 NEm and 1.32 NEg from d 83 to 109 were used, because of ingredient inventory changes. Data were analyzed using the GLIMMIX procedure of SAS 9.4 with manger space allocation as the fixed effect and block as the random effect. No differences (P > 0.35) were observed between 8IN or 16IN heifers for initial BW, final BW, average daily gain, dry matter intake, feed efficiency, variation in daily BW gain (within pen standard deviation) or applied energetic measures. No differences (P > 0.50) were observed between treatments for morbidity. Although not statistically analyzed, 8IN heifers appeared to have looser stools during the first two weeks compared with the 16IN heifers. These data suggest restricting manger space allocation from 40.6 cm to 20.3 cm did not negatively influence gain efficiency or the efficiency of dietary net energy utilization in heifers programmed fed a concentratebased diet to gain 1.36 kg daily. The use of tabular net energy values and required net energy of maintenance and retained energy equations are an effective means to program cattle to a desired daily rate of gain during the growing phase. [ABSTRACT FROM AUTHOR]

Charolais-Angus cross steers (n = 128; initial shrunk BW = 505 ± 32.1 kg; n = 16 pens; 8 replicate pens/treatment) were used in a 94-day finishing phase experiment to evaluate animal growth performance outcomes, efficiency measures, and carcass characteristics when varying degrees of ingredient inclusion tolerances were imposed. Treatments included: 1) Normal feeding with 0.454 kg tolerance for all ingredients (FXD) and 2) Variable inclusion strategy where each ingredient was randomly increased or decreased but the targeted as-fed quantity for the daily delivery was met (VAR). All steers were fed twice daily with all bunks managed using a slick bunk approach. Ractopamine HCl was fed (300 mg per head daily) for the final 28 d. Individual BW measures were captured at processing approximately every 35 d. Diets consisted of high-moisture corn (HMC), dryrolled corn (DRC), dried distillers grains plus solubles (DDGS), liquid supplement (LS), and grass hay (GH) for the first 40 days of the finishing period. Days 41-94 diets consisted of DRC, LS, DDS, GH, and corn silage (CRNSIL). Ingredient inclusions were randomized by assigning independently a random integer to HMC, GH and DDGS with each integer corresponding to the deviation from targeted inclusions; LS inclusion was held constant. As-fed inclusion rates varied from formulated targets by -20, -15, -10, -5, 0, +5, +10, +15, or +20%. DRC or CRNSIL was adjusted so that the targeted as-fed amount of the diet was delivered each day. Data were analyzed using the GLIMMIX procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) with pen as the experimental unit and block as random effect. VAR steers had increased (P = 0.01) dry matter intake (DMI) and reduced (P = 0.02) kg of gain to kg of feed (G:F). However, no differences (P = 0.75) were detected between treatments for ADG. In addition, net energy for maintenance and gain was decreased (P = 0.01) in VAR. Carcass characteristics for both treatments showed no significance (P = 0.38) in HCW, dressing percentage, rib eye area, rib fat, KPH, yield grade, retail yield, empty body fat, or body weight at 28% estimated EBF. A tendency for increased USDA marbling score (P > 0.08) was noted in VAR. Under the conditions of this experiment, randomly altering ingredient proportions did impact growth performance and efficiency measures. However, despite the difference in growth efficiency carcass characteristics were not impacted. [ABSTRACT FROM AUTHOR]

Changes to the fuel landscape in the United States have resulted in changes in long-held supplemental protein price relationships. The objective of this study was to evaluate substituting oilseed meal for corn processing co-products. Predominately Angus steers [initial shrunk body weight (BW) = 435 ± 23.6 kg] were used in a 118-d experiment using three treatments: modified distillers grains (MDGS)fed at 15% diet DM (MDGS) replaced by either soybean meal and corn (9 and 6% of DM, respectively; SBM), or soybean meal and soyhull pellets (9 and 6% of DM, respectively; SBM-SBH). Steers (n = 240) were individually weighed and allotted to one of 24 pens (n = 10 steers per pen; 8 pens per treatment) at the Southeast Research Farm located near Beresford, SD. Dietary concentrations of crude protein and neutral detergent fiber based on tabular values and weekly batching records were 12.3 and 17.6%, 12.8 and 14.5%, and 12.8 and 17.8% for MDGS, SBM, and SBM-SBH, respectively. Data were analyzed as a randomized complete block design using the GLIMMIX procedure of SAS 9.4 with treatment and block as fixed effects; pen was the experimental unit. Pen conditions were wet and muddy during the final weeks of this experiment; consequently, final BW was calculated by dividing hot carcass weight (HCW) by a common dressing percentage of 62.5. No differences amongst treatments (P = 0.11) were found for carcass-adjusted final BW, dry matter intake (DMI), average daily gain (ADG), or feed efficiency. Dietary treatment had no effect (P = 0.11) on HCW, dressing percentage, ribeye area, rib fat, marbling score, USDA Yield Grade, percent empty body fat (EBF), or final BW adjusted to 28% EBF. Distribution of USDA Quality and Yield grades were unaffected by treatment (P = 0.39). Dietary treatment did not affect liver abscess incidence and severity (P = 11). Net energy values calculated from animal performance agreed closely with tabular estimates with observed to expected ratios for net energy equaling one. In this experiment, feeding supplemental protein sources with enhanced diet conditioning attributes and greater concentrations of ruminally undegradable protein provided no advantage to cattle performance. These results indicate that protein source decisions can be based upon price per unit of delivered crude protein. [ABSTRACT FROM AUTHOR]

Cereal rye is used to diversify crop rotations in the Northern Great Plains and can be harvested through grazing, processed as forage (hay or silage), or allowed to reach maturity for grain and straw. Although rye has not traditionally been used in growing and finishing cattle diets due to the occurrence of ergot. Recent hybrid germplasms have shown promise with increased yields and decreased ergot incidence. This study aimed to determine the effects of substituting dry-rolled or ground hybrid rye for dry rolled corn (DRC) on dry matter intake (DMI), growth performance and gain:feed (G:F) of growing beef steers. One-hundred-fifty crossbred steers [260 ± 22.3 kg, initial body weight (BW)] were transported to the Carrington Research Extension Center near Carrington, North Dakota, stratified by BW, and assigned to one of fifteen pens (n = 10 steers/pen) and three dietary treatments in a randomized block design. Hybrid rye was substituted on a dry matter basis for DRC as follows: a basal diet formulated 33.8% corn silage, 23.6% forage barley hay, 17.5% modified distillers grains and solubles (MDGS), and 3% supplement and limestone with either 22.1% DRC (CON), 22.1% dry rolled hybrid rye (RRYE), and 22.1% ground hybrid rye (GRYE) on a dry matter basis. Due to extreme cold windchill temperatures, steers were fed for a total of 64 days beginning October 24, 2022. Body weights were taken before feeding on Day 1, 2, 28, 63, and 64 with a 4% pencil shrink applied to the initial and final BW. Performance data including animal BW, average daily gain (ADG), DMI and G:F ratio were calculated. The monthly average of growth performance were analyzed using the repeated measures procedure of PROC MIXED in SAS 9.4 with pen serving as the experimental unit. Pre-planned contrasts (control vs rye; rolled rye vs ground rye, rolled rye vs control, and ground rye vs control) were analyzed. No differences in BW (P = 0.35), ADG (P = 0.19), DMI (P = 0.83), or G:F (P = 0.21) were detected due to the replacement of DRC with hybrid rye throughout the study (Table 1). Steers assigned to GRYE had increased G:F (P = 0.04) and tended (P = 0.05) to have greater ADG compared with RRYE throughout the study. Steers fed hybrid rye tended to have lesser BW (P = 0.06) than those fed DRC after the first 28-day weigh period. During the final 36 days, steer assigned to GRYE had increased ADG (P = 0.03) compared with RRYE and tended (P = 0.05) to have greater ADG than those assigned to CON. Results from the study suggest that steers fed processed hybrid rye grain in a high forage backgrounding diet performed similarly to calves fed DRC. [ABSTRACT FROM AUTHOR]

The objective was to investigate the influence of cattle origin and region of finishing on the prevalence of Salmonella, Escherichia coli O157:H7, and select antimicrobial resistance in E. coli populations. Yearling heifers (n = 190) were utilized in a 2 × 2 factorial arrangement. Heifers (n = 98) in the northern region were sourced from South Dakota (SD) while heifers (n = 92) in the southern region were sourced from Texas (TX). After feedlot arrival in each respective region, fecal Salmonella prevalence was determined, and heifers were sorted into 1 of 4 treatments: heifers sourced from SD and finished in SD (SD-SD); heifers sourced from SD and finished in TX (SD-TX); heifers sourced from TX and finished in SD (TX-SD); heifers sourced from TX and finished in TX (TX-TX). Transport for SD-TX and TX-SD heifers occurred on d 0. Fecal, pen, and water scum line (WSL) samples were collected longitudinally throughout the study; hide and subiliac lymph node (SLN) samples were collected at study end (d 78 for heifers finished in TX and d 90 for heifers finished in SD). A treatment × time interaction was observed (P = 0.01) for fecal Salmonella prevalence, with prevalence being greatest for TX-TX and TX-SD heifers before transport. From d 14 through study end, prevalence was greatest for TX-TX and SD-TX heifers compared with SD-SD and TX-SD heifers. The TX-SD heifers had a 72% decrease in Salmonella prevalence from d 1 to harvest, whereas the SD-TX heifers had a 2,200% increase in Salmonella prevalence from d 1 to harvest. Salmonella prevalence on hides were greater (P = 0.01) for heifers finished in TX compared with SD. Salmonella prevalence in SLN tended (P = 0.06) to be greater in TX-TX and SD-TX heifers compared with TX-SD and SD-SD. Fecal E. coli O157:H7 prevalence had a treatment × time interaction (P = 0.04), with SD-TX prevalence being greater than TX-SD on d 56 and SD-SD and TX-TX being intermediate. A treatment × time interaction was observed for fecal trimethoprim-sulfamethoxazole-resistant and cefotaxime-resistant E. coli O157:H7 prevalence (P ≤ 0.01). Overall, these data suggest region of finishing influences pathogenic bacterial shedding patterns, with the initial 14 d after feedlot arrival being critical for pathogen carriage. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to determine if electrolyte application (glycerol-based electrolyte solution containing potassium chloride, acetic acid, magnesium hydroxide, sodium propionate, and sodium chloride; 5.10% potassium, 1.00% sodium, and 0.87% magnesium; HydraFit--Micronutrients USA LLC, Indianapolis IN) before shipping for harvest increased cold carcass weight in beef steers. Steers (n = 40; 20 steers per treatment; BW = 659 ± 72.9 kg) were weighed 40 h before harvest, blocked by BW (n = 4 BW blocks), and assigned to one of two treatments: no HydraFit (Con) or HydraFit (HF) added to the water at 4% vol/vol (4 pens/treatment, 8 pens total). Feed and water access was not restricted nor was a shrink percentage applied to any BW measures. Thirty-six hours before harvest a 378 L water tank was filled with water from the same source the steers had been consuming since arrival. Water and feed were introduced at 36 h before harvest. Final BW was captured immediately before shipping (12 h prior to harvest). Cattle were transported 98 km to a commercial abattoir. Cattle were held in lairage with ad libitum access to water before harvest the following morning. Water intake pre-shipment was determined after the cattle were removed from the pens and transported to slaughter. Water volume was estimated by measuring water depth remaining in the tank. Depth measurements were calibrated to water volume by metering (DM-P; Assured Automation, Roselle, NJ; ± 1.0%) 0.64 cm of water into each tank and recording the liters of water metered. Hot carcass weight was determined at the time of slaughter and cold carcass data was determined after a 48-hour chill. One steer from Con was condemned at the abattoir for reasons unrelated to treatment, consequently, the contribution of this steer to the pen mean was deleted. Providing HF in the drinking water for approximately 22 hours before shipping for harvest tended to increase final body weight (P = 0.08) by 1% but had no effect (P = 0.88) on hot or cold carcass weight. In conclusion, providing a glycerol-based electrolyte solution to finished beef cattle for approximately 22 hours before shipping for harvest tended to improve final body weight. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine if additional roughage inclusion to feedlot steer finishing diets during the feeding of ractopamine hydrochloride (RH) is an effective method to improve rumen health and control liver abscess severity. Steers [n = 64; initial shrunk body weight (SBW) = 633 kg ± 35.1 kg] were sourced from an unrelated trial and remained in their previous study pens; pens (n = 8) were assigned to dietary treatment in a completely randomized design. All steers on trial were fed a common 7% [dry matter (DM) basis] roughage equivalent (RE) finishing diet composed of dry-rolled corn, dried distillers grains plus solubles, corn silage, and grass hay for the 58 d preceding study initiation. Steers were fitted with rumination tags to track daily rumination. Dietary treatments were CON: no diet change; and 12R: 5% (DM basis) RE addition to diet via grass hay during the feeding of RH. Steers were fed RH (300 mg/steer/d), finished on treatment diets for 28 d, and harvested at a commercial beef processor. Growth performance, efficiency of dietary net energy (NE) utilization, and continuous carcass data were analyzed with pen as the experimental unit (EU) and fixed effect of treatment. Minutes ruminating was analyzed as an analysis of covariance with individual animal as the EU, fixed effects of treatment, days on feed (DOF) and their interaction, and baseline minutes ruminating as a covariate in the model. Liver abscess prevalence, rumen health, and categorical carcass data were analyzed with the Fisher's exact test to determine differences between treatments. No difference (P ≥ 0.19) was observed for final SBW, average daily gain, dry matter intake, feed conversion efficiency, dressing percentage, hot carcass weight, calculated yield grade, marbling score, 12th rib fat thickness, calculated empty body fat, observed dietary NE for maintenance and gain, observed-to-expected dietary NE for maintenance and gain, or distribution of liver abscess prevalence, ruminitis score, or USDA yield grade. Ribeye area tended (P = 0.10) to differ between treatments with 12R steers exhibiting a 3.5% larger ribeye. Distribution of USDA quality grade differed (P = 0.003) between treatments with 12R steers having 25% more carcasses grading USDA average choice or better. A treatment × DOF interaction (P = 0.045) was observed for minutes ruminating per day. Daily minutes ruminating was increased (P ≤ 0.05) for 12R on d 1, 2, and 20 and tended to be increased (P ≤ 0.10) for 12R on days 10, 13, 24, and 25. Inclusion of an additional 5% RE to finishing cattle diets during a 28 d RH feeding period can be a management strategy to decrease risk of digestive upsets without sacrificing growth performance or carcass quality. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the influence that a rumen-protected B-vitamin (RPBV) blend (containing pantothenic acid, pyridoxine, folic acid, biotin, and cyanocobalamin; Vivalto, Trouw Nutrition, Isola Vicentina, Italy) had on growth performance, efficiency of dietary net energy utilization, carcass trait responses, and liver abscess severity and prevalence in beef steers fed a finishing diet. Steers (n = 246; initial shrunk body weight (BW) = 411 ± 25.8 kg) from two sources, were used in a 126-d randomized complete block design experiment. Within 48 h after arrival, steers were individually weighed and allotted to one of 24 pens (n = 10 to 12 steers; 8 pens/treatment) and randomly assigned to 1 of 3 treatments: 1) No RPBV; 2) RPBV1 at 1 g/hd/d; 3) RPBV2 at 2 g·animal-1·d-1/. During the first 14 d cattle received two transition diets. From d 15 to d 126 cattle were fed the final diet containing 53% dry-rolled corn; 23% corn silage; 20% MDGS; and 4% suspended supplement. Data were analyzed using the GLIMMIX procedure of SAS 9.4 with treatment as the fixed effect and block (Pen location) as the random effect; pen was considered the experimental unit. No differences (P ≥ 0.13) were found for dry matter intake, final live BW, average daily gain (ADG), or feed efficiency (G:F) among treatments. Carcass-adjusted final BW, ADG, and G:F were not influenced by treatment (P ≥ 0.59). Hot carcass weight, dressing percentage, marbling score, kidney-pelvicheart fat, or BW at 28% empty body fat did not differ among treatments (P ≥ 0.11). Rib eye area (REA) was altered (quadratic effect, P = 0.02) by treatment; steers from RPBV 1g had decreased REA compared with others. Additionally, calculated yield grade (YG) and calculated retail yield (RY) were altered (quadratic effect, P = 0.01) by treatment; steers from RPBV 1 g had increased YG and decreased RY compared with others. Estimated empty body fatness tended (P = 0.06) to be greater from steers fed RPBV compared with control. Overall USDA YG distribution was altered by dietary treatment (P = 0.01). The proportions of YG1 and YG5 carcasses were unaffected by treatment, but there was a shift in the proportion of carcasses that graded YG2, YG3, and YG4 among treatments. Distribution of USDA Quality Grade was not altered by treatment (P = 0.53). No differences were observed on liver abscesses among treatments. The use of RPBV altered carcass muscularity and rib fat accumulation which impacted the overall YG distribution. However, RPBV did not appreciably influence any cumulative growth performance measures liver abscess incidence or severity. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of CaMg(CO3)2 (MIN-AD, Papillon Agricultural Company, Easton, MD; MA) and/or tylosin phosphate (Tylan, Elanco, Indianapolis, IN; TY) supplementation on growth performance of yearling beef steers during transition to a finishing diet during the first 28 days on feed. Treatments were arranged in a 2 × 2 factorial arrangement including MA and TY. Beef steers (n = 156; initial BW = 469 ± 18.0 kg) were randomly assigned to dietary treatments pens (7 to 8 steers/pen) with pen (n = 20 pens total, 10 pens/main effect mean, and 5 pens/simple effect mean) serving as the experimental unit. Cattle were transitioned from a 30 % roughage receiving diet to a 7 % roughage finishing diet based on dry-rolled corn, dried distillers grains plus solubles, a liquid supplement, and oat silage over the initial 20 d period. Monensin sodium was included in the diet at 30 mg/kg (DM basis). The MA was included at 1.5 % of the diet (DM basis) in replacement of dry-rolled corn and TY was provided at 90 mg/animal·d-1. Data were analyzed according to a randomized complete block design with the fixed effects of MA, TY, or their interaction; block was considered a random effect. No interaction was noted between MA or TY (P ≥ 0.68) for any variables measured. The main effect of TY did not influence d 28 BW, ADG, DMI, or G:F (P ≥ 0.43). The main effect of MA reduced DMI by 1.9 % (P = 0.01), but did not appreciably influence d 28 BW, ADG, or G:F (P ≥ 0.42). MA may decrease DMI while maintaining similar BW gain and efficiency compared with non-supplemented calves. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of orally administered Megasphaera elsdenii NCIMB 41125 (ME) in preconditioned calves abruptly transitioned from a receiving diet with 4% dietary starch [dry matter (DM) basis] to a growing diet with 37% dietary starch (DM basis). Preconditioned steers [n = 192; initial shrunk body weight (SBW) = 309 kg ± 20.6 kg] were assigned to microbial supplement treatment in a randomized complete block design. Treatments were CON: no ME; and LP: orally administered 20 mL of microbial supplement (2 × 1010 colony forming units ME/mL) immediately before diet change. Steers were abruptly changed from a receiving diet based upon soybean hulls and wheatlage with 4% dietary starch (DM basis) to a growing diet based upon high-moisture ear corn, dry-rolled corn, and wheatlage with 37% dietary starch (DM basis). Diets were switched on an equal DM basis to achieve abrupt change and steers were fed treatment diet for 49 d until study completion. Prior to study initiation, steers (n = 72; n = 3/pen) were fitted with wireless rumination tags to track daily activity and rumination time. Growth performance data and efficiency of dietary net energy utilization were analyzed with pen as the experimental unit, fixed effect of treatment, and random effect of block (location in the feedlot). Activity and rumination data were analyzed in a repeated measures analysis of covariance with individual animal as experimental unit, fixed effects of treatment, week, and their interaction, block (location in feedlot) as a random effect, and baseline activity and rumination as a covariate in the model. If no interaction was observed, main effect means of treatment and week were evaluated independently. For all statistical analysis, P ≤ 0.05 was declared significant and P ≤ 0.10 was declared a tendency. No difference (P ≥ 0.20) was observed between treatments for final SBW, average daily gain, dry matter intake, feed efficiency, calculated net energy (NE) for maintenance and gain or observed-to-expected ratio of NE for maintenance and gain. Additionally, no treatment × day differences (P ≥ 0.27) were observed for activity or rumination measures. Treatment effects (P < 0.01) were observed for both activity and rumination where LP steers had a 2% increase and 2% decrease in minutes per day active and ruminating respectively. Additionally, a positive linear effect (P < 0.01) of week was observed for minutes ruminating and quadratic effects (P < 0.01) of week were observed for minutes active and ruminating. Oral administration of ME had no effects on growth performance or efficiency of dietary net energy utilization in steers transitioned from a receiving diet containing 4% starch (DM basis) to a growing diet containing 37% starch (DM basis). [ABSTRACT FROM AUTHOR]

The objective of the study was to determine the influence that initial BW has on growth performance responses, efficiency of dietary net energy (NE) utilization, and carcass traits in feedlot steers. Crossbred Charolais steers from a single source, (n = 70; initial BW = 329 ± 72.6 kg) were used in feedlot experiment at the Ruminant Nutrition Center, in Brookings, SD, during a 209-day growing-finishing period. These steers represented the lightest and heaviest proportions of steers taken from a larger group of 265 steer calves. On d 0 and d 1 BW and hip height (HH) measurements were collected for allotment proposes, and the initial experimental BW was the average between d 0 and d 1 BW. Steers were allocated to 1 of 2 treatments: 1) lighter (276 ± 16 kg; LIW) or 2) heavier (356 ± 16 kg; HIW) initial BW and allotted to 10 pens (n = 7 steers/pen; 5 pens/treatment). Steers were fed a diet containing 16% roughage once daily. Data were analyzed as a randomized complete block design with pen as the experimental unit. Treatment was included as a fixed effect and block (location) was considered a random effect in the statistical model. The LIW steers had a greater cumulative HH change compared with HIW. Final BW and carcass-adjusted (HCW/0.625) BW were greater for HIW steers by 13.1% and 13.4% respectively (P = 0.01). The HIW steers had a 14.4% greater DMI (P = 0.01) compared with LIW. Cumulative ADG was greater for HIW by 3% (P = 0.04). LIW steers had improved feed conversion (P = 0.01) by 11.3% compared with HIW. The HIW steers had greater (P < 0.05) HCW (15.5%), marbling scores (6.8%), and Yield grade (16.0%), and decreased REA/HCW (P = 0.01) by 5.9% compared with LIW. Steers from HIW tended to have greater rib fat (P = 0.09) by 15% compared with LIW. The distribution of USDA Yield grade was altered by initial BW (P = 0.04) with a shift in proportions of steers with greater numerical Yield grades for steers in HIW compared with LIW. No differences were detected (P = 0.22) for the distribution of Quality grade or liver abscess prevalence and severity. In conclusion, HIW steers had greater growth, but poorer feed efficiency compared with LIW steers. Steers with a HIW produced fatter carcasses with a greater amount of marbling. [ABSTRACT FROM AUTHOR]

Predominantly Angus steers were used in a 147-day randomized complete block design experiment (RCBD) to evaluate the effects of rye processing method on growth performance, feed efficiency, and carcass characteristics. Steers [n = 192, initial body weight (BW) = 410 ± 20.9 kg] were individually weighed and allotted to 1 of 24 pens (n = 8 steers/pen; 6 pens/treatment). Four treatments were used where hybrid rye grain (total ergot alkaloid concentration = 1,007 ppb, DM basis) was processed using three different methods [unprocessed (UP); dry-rolled (DR); or hammer-milled (HM)] fed at 17% of diet DM along with 43% dry-rolled corn (DRC) compared with a control diet containing 60% DRC on a DM basis (CON). Data were analyzed as an RCBD using the GLIMMIX procedure of SAS with treatment as the fixed effect and block (Pen location) as the random effect; pen was the experimental unit. No differences (P = 0.44) were observed among treatments for live final BW or average daily gain (ADG). Dry matter intake (DMI) was greater for HM (12.27 kg) compared with CON and DR (11.84 and 11.48 kg, respectively) with DR having 4.9% less DMI compared with UP (P = 0.01; SEM = 0.200). UP and HM treatments tended to have 4.8% poorer G:F compared with CON and DR (P = 0.07). Dietary treatments did not affect carcass traits, percent empty body fatness (EBF), or final BW at 28% EBF (P = 0.23). Distributions of USDA Quality or Yield grades were unaffected by treatment (P = 0.23), nor was the incidence or severity of liver abscesses (P = 0.25). Estimated NEm and NEg values of the diet for UP (1.90 and 1.26 Mcal/kg, respectively) were reduced compared with CON and DR (1.98 and 1.32 Mcal/kg, respectively), with HM intermediate (P = 0.05, SEM = 0.033 and 0.029 for NEm and NEg, respectively). Net energy values for UP and HM rye were within 7% of current feeding standards when calculated using the substitution method. Rolling increased apparent ingredient NEg for rye by 30.1% compared with UP or HM rye. Processing rye grain by dry-rolling increased dietary net energy values and tended to improve gain efficiency compared with not processing or using a hammer mill. Rye grain can be partially substituted for DRC with negligible impact on growth performance or carcass measures. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of kernel processing of corn silage on apparent total tract digestibility (ATTD) of steers fed corn silage included at 65% of the diet (DM basis). Steers (n = 184; initial shrunk BW = 338 ± 22.3 kg) were assigned to 1 of 24 pens (8 steers/pen). Pens were randomly assigned to one of two dietary treatments (12 pens/treatment): non-kernel processed corn silage included at 65% diet DM (CON) or kernel processed corn silage included at 65% diet DM (KPCS) in a randomized complete block design with pen as experimental unit. Steers from replicates 1 to 8 spent 47-d on test and steers from replicates 9 to 12 were fed for 46-d on test. On the final day of the study, apparent total tract digestibility of diet dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), N, and starch was determined using an internal marker ratio technique using the undigested NDF residue following a 240 h in-situ incubation in ruminal fluid (uNDF240). Diet samples were collected twice daily (morning and afternoon) starting two days prior to fecal collections. Fecal collections were taken via rectal palpation on the final day of the study. Data were analyzed as a RCBD with fixed effects of KPCS diet and random effect of block (location within feedyard). Kernel processing increased DMI by 6% (P = 0.01) during the collection period and cumulative DMI throughout the study was increased by 2% for KPCS treatment (P = 0.04). Kernel processing did not enhance the ATTD of DM, OM, or starch (P = 0.71), but did decrease ATTD of NDF by approximately 6% (P = 0.04) compared with corn silage that was not kernel processed. Furthermore, kernel processing was determined to increase ATTD of N by 5% (P = 0.05). These results indicate that kernel processed corn silage may decrease apparent total tract digestibility of neutral detergent fiber due to greater intake but does not appreciably influence starch digestibility. [ABSTRACT FROM AUTHOR]

Angus heifers (n = 60; initial shrunk BW = 460 ± 26.2kg in n = 10 pens; 5 replicate pens/treatment) were used in a 112-d feedlot finishing experiment to evaluate animal growth performance outcomes, efficiency measures, and carcass characteristics when varying degrees of ingredient inclusion tolerances were imposed. Treatments included: 1) Normal feeding with 1lb tolerance for all ingredients (FIXED). 2) Variable inclusion strategy where each ingredient was randomly increased or decreased but the targeted as-fed quantity for the daily delivery was met (VAR). All heifers were fed once daily with all bunks managed using a slick bunk approach. Monensin sodium was fed at 33mg/kg and ractopamine HCl was fed (300mg per head daily) the final 28d. Individual BW measures were captured at processing and every 21d. Diets consisted of earlage, dried distiller's grains, and a liquid supplement. Ingredient inclusions were randomized by assigning independently a random integer to DDGS and LS with each integer corresponding to the deviation from targeted inclusions. Earlage inclusion was adjusted so that the targeted as-fed amount of the diet was delivered. As-fed inclusion rates varied from formulated targets by -20, -15, -10, -5, 0, +5, +10, +15, or +20%. Actual DM inclusion was within 5% of expectations 72% of the time in FIXED (13periods/18periods) and only 27% of the time in VAR (5periods/18periods). Ingredient inclusion accuracy did not affect ADG, DMI, or feed conversion efficiency in this experiment (P ≥ 0.15). DMI and liquid inclusion rates showed an inverse relationship. There were no differences (P ³ 0.35) detected between treatments for carcass characteristics. No differences were noted between dietary treatments for liver abscess prevalence or severity. Under the conditions of this experiment, randomly altering ingredient proportions did not affect live animal performance, efficiency measures, or carcass characteristics. [ABSTRACT FROM AUTHOR]

For years, researchers have quantified and appraised feed additives, steroidal implants, and various management strategies, such as grain processing, limit feeding, or slick-bunk management, on the sole basis of responses in rate and efficiency of gain. Until recently, cattle were mainly sold on live basis; however, many cattle fed today are marketed on a carcass value basis. Cattle uniformity at slaughter is important economically for cattle producers, particularly for those trying to meet grid standards and minimize carcass discounts. Management factors to control rate of growth from 50 to 65% of final shrunk body weight, program feeding a high-concentrate diet to achieve targeted rates of gain, or by offering ad libitum access to forage-based diets can be used to delay fattening. Delaying fattening allows cattle to achieve heavier weights at similar final fat content. Management factors to control intake early in the feeding period to reduce weight gain variation, or using terminal sorting, allows for increased uniformity of cattle loads at harvest. Sensor-based sorting technologies can allow for cattle to be placed in similar contemporary groups to minimize discounts at the lot level when pens of cattle are marketed. Pharmaceutical technologies such as steroidal implants delay fattening and allow for increased harvest weight of cattle. Betaadrenergic agonist application during the final weeks prior to harvest enhances muscle growth at the expense of fat deposition, allowing for improved feed efficiency during the late feeding period and increased days on feed. Complementary breeding systems that capitalize on terminal sires mated to maternal lines adapted to specific environments would generate cattle optimized for growth potential and carcass weight. This presentation will review factors impacting carcass end goals and future research needs to improve understanding of how management and technology influence growth composition, attainment of carcass end goals, and economic returns. [ABSTRACT FROM AUTHOR]

The objective was to determine if delivery method of organic trace minerals and Saccharomyces cerevisiae yeast culture product influence growth performance, feed efficiency, and hepatic trace mineral measures in newly-weaned steers. Crossbred steers (n = 192; 256 ± 14 kg) were used in a 49-d receiving experiment. Within 36h of weaning, steers were weighed, allotted to 24 pens (n = 8 steers/pen; 8 pens/treatment) and randomly assigned to treatments: traditional receiving diet (Con); traditional receiving diet plus the "stress-pack" directly in the diet (Force); traditional receiving diet plus a low-moisture, cooked molasses block fortified with the "stress-pack" (Tub). "Stress-pack" was offered the first 28 d of the 49-d. Biopsy samples were collected from a subsample of steers (n = 14 steers) on the day of weaning and subsequent samples were collected from the same steer (n = 1 steer/pen) on d 14, 28 and 49 for hepatic trace mineral concentration determination. A treatment × day interaction (P=0.01) for hepatic Cu concentration was noted. Force had greater hepatic Cu (P=0.05) compared to Tub and Con for the entire period. Tub had greater hepatic Cu compared to Con on d 14 and 28 (P < 0.05), but was similar to Con on d 49 (P>0.10). Force tended (P=0.08) to have greater DMI compared to Tub from d 1 to 14. From d 15 to 28, steers offered "stresspack" had greater DMI (P=0.01) and tended (P=0.07) to have greater ADG compared to Con by 12.5%. From d 29 to 49, "stress-pack" steers had greater DMI (P=0.01) and Force consumed 6.9% more DM compared to Tub (P=0.01). Cumulative DMI (P=0.01) and ADG (P=0.05) was greater for Force compared to Tub by 5.4% and 9.4%, respectively. Application of "stresspack" in diets offered to newly-weaned cattle enhanced production responses, but delivery method influences DMI and daily gain. [ABSTRACT FROM AUTHOR]

The objective of this research was to evaluate health, growth performance, and antibody titers to IBR, BVD 1 and 2, PI3, and BRSV for calves administered a respiratory and clostridia vaccine compared with no vaccination upon arrival. Single-sourced, newly weaned steers (n = 70; initial body weight (BW) = 254±5.9 kg) were allotted to 10 pens (n = 5 pens/treatment with 7 steers/pen). Steers were blocked by BW in a RCBD of VAC (vaccinated for IBR, BVD 1 and 2, PI3, and BRSV and clostridial upon arrival) or NOVAC (not vaccinated upon arrival). Steers were individually weighed on d 0 (arrival), 1, 21, and 42 for growth performance measures. Whole blood samples were collected (n = 3 steers/pen closest to the pen mean BW) on d 1, 21, and 42 via jugular venipuncture for antibody titer responses. Depression scores of 0 (normal) to 4 (moribund) were recorded for each individual steer for 21 d. Body weight gain and feed efficiency were not influenced (P = 0.10) by treatment. However, dry matter intake tended (P < 0.07) to increase as a percentage of BW by 3.5% for NOVAC compared with VAC. No treatment by day interactions (P > 0.05) were observed for depression scores or BVD 1 and 2 or PI3 titers. However, a treatment by day interaction (P < 0.03) was observed for IBR and BRSV titers. VAC steers had decreased (P < 0.05) titers for both IBR and BRSV on d 1 compared with d 21 but were similar (P > 0.05) to d 42, which were also similar (P > 0.05) to d 21 titers. Additionally, VAC steers had a 27% increase (P < 0.03) in PI3 titers compared with NOVAC steers. Collectively, growth performance was unaffected by vaccination, and vaccinated calves had increased antibody titer responses, as expected. [ABSTRACT FROM AUTHOR]

Continental × British beef heifers were used in a randomized complete block design experiment to evaluate the effects of replacing dry-rolled corn with unprocessed rye on growth performance, efficiency of dietary net energy (NE) utilization, and carcass trait responses in finishing heifers. Heifers (n = 56; 433 ± 34.0 kg) were transported 241 km from a regional sale barn to the Ruminant Nutrition Center in Brookings, SD. Heifers were blocked by weight grouping and then allotted to pens (n = 7 heifers/pen and 4 pens/treatment). Treatments included a finishing diet that contained 60% grain (DM basis) as dry-rolled corn (DRC) or unprocessed rye grain (RYE). On d 14, heifers were consuming the final diet and were implanted with 200 mg of trenbolone acetate and 28 mg of estradiol benzoate (Synovex-Plus, Zoetis, Parsippany, NJ). RYE heifers had decreased (P ≤ 0.01) final body weight, average daily gain, and gain efficiency; but tended (P = 0.08) to have a greater dry matter intake compared to DRC. RYE had decreased (P ≤ 0.01) observed dietary NE and decreased (P ≤ 0.01) observed-to-expected dietary NE ratio for maintenance and gain compared to DRC. Dressing percentage, 12th rib fat thickness, ribeye area, and the distribution of USDA yield and quality grades were not altered (P ≥ 0.12) by diet. Hot carcass weight, yield grade, estimated empty body fat (EBF), and body weight at 28% EBF decreased (P ≤ 0.02) and retail yield increased (P= 0.01) in RYE compared to DRC. These data indicate that unprocessed rye is a palatable feed ingredient for inclusion in finishing diets for beef cattle and that rye inclusion only minimally influences carcass quality. The feeding value of unprocessed rye is considerably less (21.4%) than that of dry-rolled corn using current standards and approximately 91% of the NE value of processed rye. [ABSTRACT FROM AUTHOR]

The experiment objective was to evaluate the impact of assisted reproductive technologies on post weaning calf performance. Calves born following various reproductive treatments (synchronized natural service and synchronized AI) in 10 herds over 2 years were fed to reach a target backfat (BF) of 1.27 cm, sent to harvest, and carcass data collected. Calves were classified into calving groups as natural service born early (NS-Early, n = 189), natural service born late (NS-Late, n = 203), or AI sired born early (AI-Early, n = 116). Data were analyzed using the MIXED procedure in SAS with calving group, year and calf gender in the model. Weaning weights were similar between AI-Early and NS-Early; however, earlier born calves (AI-Early and NS-Early) were heavier (P < 0.0001) than NS-Late. AI-Early calves had heavier finished bodyweight (622.2 kg: P = 0.0024) compared to NS-Early (601.4 kg) and heavier HCW compared to both NS-Early and NS-Late (P < 0.01). NS-Early calves reached 1.27 cm BF in fewer days than AI-Early (261 d and 275 d, respectively; P < 0.01) with NS-late requiring the most days on feed to reach the same endpoint (296 d, P < 0.01). No differences in Quality Grade, Yield Grade, REA, marbling, or BF were detected between AI-Early, NS-Early, and NS-Late, or between early- and late-born calves (P > 0.38). Late-born calves required 29 more days on feed (P < 0.001) to reach 1.27 cm BF resulting in greater final bodyweight compared to early-born calves (625.5 kg and 612.8 kg, respectively; P = 0.04); however, hot carcass weights were similar between early- and late-born calves. Reproductive technologies that increase the number of calves born early in the calving season increased weaning weight and post weaning growth performance, but compared to high quality natural service sires, AI did not improve carcass characteristics. [ABSTRACT FROM AUTHOR]

Yearling beef steers (n = 238; initial BW=402 ± 31.2 kg) were used to evaluate a Bacillus subtilis probiotic on growth performance, dietary net energy (NE) utilization, carcass characteristics, and fecal and subiliac lymph node Salmonella prevalence during a 140-d finishing period. Steers were allotted to 24 pens (n = 9 to 10 steers/pen) and assigned to one of two treatments (12 pens/treatment): no probiotic (CON) or 0.50 g·steer-1·d-1 of a Bacillus subtilis PB6 probiotic (CLOSTAT® 500, Kemin Industries, Des Moines, IA; CLO). Steers were transitioned to a 90% concentrate diet (DM basis) over 14-d. Steers were fed once daily at 0700 h; bunks were managed according to a slick bunk management. Fecal samples were collected on d 1, 28, 56, 112, and 140 from each pen (n = 5 steers/pen) via rectal palpation and composited by pen for determination of Salmonella prevalence. Upon harvest, subiliac lymph nodes were obtained from 60 steers in CON and 57 steers in CLO. Data were analyzed as a randomized complete block design; pen was the experimental unit; α of 0.05 determined significance. No differences were detected (P ≥ 0.25) between treatments for live or carcass-adjusted average daily gain, dry matter intake, gain efficiency, dietary NE utilization, nor calculated dietary NE content based upon performance. No differences were detected between treatments for any carcass traits (P ≥ 0.15). Salmonella was not recovered in any fecal samples except on d 112, where steers from CLO had a numerically lower (P = 0.17; 8.3 vs. 25.0%) incidence of fecal Salmonella compared to CON and on d 140 fecal, where Salmonella incidence did not differ (P = 0.34; 0.0 vs. 8.3%) for CON and CLO, respectively. Salmonella was not recovered in any subiliac lymph nodes. These data indicate that CLO did not influence growth performance or Salmonella prevalence. [ABSTRACT FROM AUTHOR]

A single corn hybrid was used to evaluate harvest maturity (Mat) and/or kernel processing (KP) effects on corn silage processing score (CSPS) and particle size (PS). Treatments were arranged in a 2 × 2 factorial of 1) Mat (early and late) and 2) KP (no or yes). A single corn field was planted on April 27, 2020. There were 12 loads (experimental unit) per simple effect treatment mean. Data were analyzed as a completely randomized design. Early harvest occurred on August 28, 2020 [yield (as is) = 39.1 Mg/hectare; DM = 43.1%; CP, NDF, and starch = 6.5, 46.0, and 32.9%, respectively (DM basis)]. Late harvest occurred on September 9, 2020 [yield = 37.8 Mg/hectare (as is); DM = 49.2%; CP, NDF, and starch = 6.6, 49.8, and 37.5%, respectively (DM basis)]. The same equipment was used for both Mat with KP achieved by narrowing processing rollers. The CSPS was determined as the proportion of starch retained below a 4.75-mm sieve. Grain content (DM basis) of the corn silage was calculated from starch/0.72. Particle size was assessed using the Penn State Particle Separator. A Mat × KP interaction (P = 0.05) was detected for CSPS. Early/no and late/no had decreased (P ≤ 0.05) CSPS compared to early/yes and late/yes had the greatest CSPS (P ≤ 0.05) compared to others. Grain content was 13.9% greater in late compared to early (P = 0.01). A Mat × KP interaction (P = 0.03) was detected for PS. Early/no had the greatest (P ≤ 0.05) PS, early/yes and late/no were intermediate, and late/yes had decreased PS compared to others (P ≤ 0.05). These data indicate that Mat and KP influence CSPS synergistically. Producers should consider KP when corn silage is harvested at a later maturity to enhance CSPS. [ABSTRACT FROM AUTHOR]

One hundred ninety-two Continental × British steers (initial BW 420 kg [SD 24.7]) were used in a randomized complete block design finishing study to evaluate the effects of feeding two types of silage germplasm at two inclusion rates. A 2 × 2 factorial arrangement of treatments was used with either a conventional (CON) or increased expression of alpha-amylase (Enogen, Syngenta Seeds, LLC, ENO) hybrid fed at either 12% (12SIL) or 24% (24SIL) of diet DM. Steers were blocked (n = 5) and assigned randomly within block to treatments, resulting in five pens and 48 steers per treatment. Steers were harvested after 126 (12SIL) or 140 (24SIL) days on feed. There were no silage source by inclusion rate interactions detected for live growth performance. Silage source did not affect live based average daily gain (ADG), gain to feed ratio (G:F), or final BW (FBW; P = 0.35). Feeding 24% silage reduced ADG (P = 0.04) and G:F (P = 0.01) but increased FBW (P = 0.02) compared to 12SIL. A source by inclusion rate interaction was detected (P = 0.04) for calculated yield grade (YG) with steers fed 24% silage having increased YG within CON but not ENO. Hot carcass weight and ribfat were unaffected by silage source (P = 0.81), but were increased by feeding 24% silage (P = 0.03 and P = 0.02, respectively). Feeding increased amounts of silage increased beef produced per hectare (P = 0.05). Conventional silage produced more beef per hectare (P < 0.01) due to differences in silage yield, but source of silage did not affect feedlot performance independent of silage yield. Feeding increased amounts of silage reduced DM efficiency on a live animal basis but increased beef produced per hectare which is of major value to cattle feeders who produce the majority of their own feedstuffs. [ABSTRACT FROM AUTHOR]

Producers are turning to mobile and Web-based decision-making tools in increasing numbers to better manage their businesses. To assist livestock producers in evaluating feed options, a "Feed Cost Calculator" was developed as an app for iOS, Android, and Web-based platforms. Mobile applications are a viable alternative to spreadsheet tools to address the needs of Extension clientele; however, there are certain inherent limitations to using mobile technology that must be considered. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to evaluate the effects of orally administered Megasphaera elsdenii NCIMB 41125 as a microbial supplement in steers abruptly transitioned from a receiving diet with 4% dietary starch (dry matter [DM] basis) to a growing diet with 38% dietary starch (DM basis). Steers ( n  = 192; initial shrunk body weight [SBW] = 309 ± 20.6 kg) were assigned to microbial supplement treatment in a randomized complete block design. Treatments were control (CON): no microbial supplement prior to diet transition, and (DFM): microbial supplement orally administered prior to diet transition (20 mL of microbial supplement [Lactipro NXT, Axiota Animal Health, Fort Collins, CO] containing 1 × 10 10 colony forming units Megasphaera elsdenii NCIMB 41125). Steers were sourced from a previously conducted 49 d feedlot receiving period experiment and abruptly transitioned from a receiving diet including soybean hulls and wheatlage containing 4% dietary starch (DM basis) to a growing diet including high-moisture ear corn, dry-rolled corn, and wheatlage containing 38% dietary starch (DM basis). Diets were switched on an equal DM intake basis to achieve the abrupt change and steers were fed the 38% starch diet for 49 d until experiment completion. Prior to experiment initiation, steers ( n  = 72; n  = 3/pen) were fitted with wireless rumination tags to track daily activity and rumination time. No differences ( P  ≥ 0.20) were observed between treatments for final SBW, average daily gain, DM intake, feed efficiency, calculated net energy (NE) for maintenance and gain, or observed-to-expected ratio of NE for maintenance and gain. Additionally, no treatment × day or treatment differences ( P  ≥ 0.12) were observed for activity or rumination measures. Minutes ruminating and active both differed ( P  < 0.01) for the main effect of day. Compared to non-supplemented steers, oral administration of Megasphaera elsdenii NCIMB 41125 did not improve growth performance or efficiency of dietary NE utilization in steers transitioned from a receiving diet containing 4% starch (DM basis) to a growing diet containing 38% starch (DM basis)., Competing Interests: No potential conflict of interest is reported by F.L.F. or W.C.R. other than the fact that Axiota Animal Health (Fort Collins, CO, USA 80528) provided the Lactipro NXT product in-kind. Z.K.S. has provided consulting services for Axiota Animal Health., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Objective: The objective of this study was to determine if a formulated blend of capsicum oleoresin, clove essential oil, and garlic essential oil (Fytera® Advance - Selko® USA, Indianapolis IN; CCG) influences measures of cattle growth, efficiency, or carcass traits, during the finishing phase in steers fed a concentrate-based diet., Methods: Charolais × Angus steers (n = 96; initial shrunk BW = 391± 34.0 kg) were used in a 144-d (16 February 2023 to 9 July 2023) finishing feedlot experiment in Brookings, SD. Steers were individually weighed and allotted to one of 14 pens (6 to 7 steers; 7 pens/treatment) in a randomized complete block design and randomly assigned to 1 of 2 treatments: control diet without the test product (CON) or a diet including CCG at 500 mg/steer daily (CCG). Steers were fed twice daily, and bunks were managed according to a slick bunk system., Results: There were no differences (P ≥ 0.10) in any growth performance outcomes from d 1 to 35, 36 to 70, or 71 to 98. From d 99 to 144 steers from CCG tended to have 5% greater ADG (P = 0.09) and 8% improved G:F (P = 0.01). No differences (P ≥ 0.15) were noted for cumulative growth performance measures. No differences were noted for any carcass measurements or categorical carcass outcomes, nor lung or liver health outcomes (P ≥ 0.15)., Conclusion: The use of CCG had no influence on cumulative growth performance responses. However, the use of CCG improved G:F during the late feeding period.

The objective was to determine the influence of long-term supplementation (258 d) of a direct-fed microbial (DFM) and/or yeast cell wall (YCW) product on bacterial populations in beef steers. Single-sourced Charolais × Red Angus steers (n = 256; body weight = 246 ± 1.68 kg) were used in a randomized complete block design and blocked by location into one of four treatments: 1) fed no DFM and no YCW (Control); 2) fed only the DFM (DFM; Certillus CP B1801 Dry, 28 g/steer d-1 ); 3) fed only the YCW (YCW; Celmanax; 18 g/steer d-1 ); and 4) fed the DFM and the YCW (DFM+YCW). Steers were vaccinated for respiratory and clostridial diseases and treated for internal and external parasites at processing and individually weighed on days 1, 14, 42, 77, 105, 133, 161, 182, 230, and 258. To determine bacterial prevalence, fecal samples were collected on days 1, 14, 77, 133, 182, and 230 and environmental (pen area, feed, and water) samples were collected at the beginning of the week when cattle were weighed. No treatment × day interactions or treatment effects (P > 0.05) were observed between treatment groups at any sampling days for the bacterial populations. Samples on days 1, 133, and 182 had greater (P < 0.05) Clostridia levels compared to the other sampling points but were not different from each other. Clostridia levels were also greater (P < 0.05) on day 77 compared to days 14 and 230. Samples on days 77 and 230 had greater (P < 0.05) Clostridium perfringens levels compared to the other sampling points but were not different (P > 0.05) from each other. Samples on days 1 and 14 had lower (P < 0.05) total Escherichia coli levels compared to the other sampling points but were not different (P > 0.05) from each other. Escherichia coli levels on day 77 were higher (P < 0.05) compared to days 133, 182, and 230. Little Salmonella prevalence (1.5%) was observed throughout the study. This study had greater levels of Clostridia compared to small and large commercial feedlots in the Church and Dwight research database, but C. perfringens, total and pathogenic E. coli, and Salmonella prevalence were notably lower. Collectively, there were no appreciable treatment influences on bacterial populations. These data further indicate a low pathogenic bacterial challenge at the trial site, which could partially explain the lack of differences with DFM or YCW supplementation. The DFM and YCW used alone or in combination cannot be expected to show additional benefits when animals are relatively unstressed with a low pathogenic bacterial challenge., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)