Influence of long-term supplementation of a formulated botanical blend on growth performance and carcass traits in feedlot steers.

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.

Evaluation of long-term supplementation of a Bacillus subtilis direct-fed microbial and enzymatically hydrolyzed yeast cell culture product used alone or in combination on Clostridia, Clostridium perfringens, Escherichia coli, and Salmonella prevalence in beef steers.

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 ±â€…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 objective of this research 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. 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 further explain the reasons for little differences. The DFM and YCW used alone or in combination cannot be expected to show productive benefits when animals are relatively unstressed with a low pathogenic bacterial challenge.

Effect of Lighter and Heavier Initial Weight on Growth Performance and Carcass Traits of Single-Source Beef Steers.

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. Charolais×Red Angus steers (n = 70) selected from a larger single-source group were used in a 209-d growing-finishing feedlot experiment. Steers were assigned to two groups based on initial BW (light initial weight, LIW = 273 ± 16.0 kg; heavy initial weight, HIW = 356 ± 14.2 kg) and allotted into 10 pens (n = 7 steers per pen; 5 pens per experimental group) the within pen standard deviation for LIW was from 14.1 kg to 20.9 kg and for HIW was from 13.7 kg to 16.0 kg. Steers were fed a common diet once daily. Experimental data were analyzed as a randomized complete block design with pen as the experimental unit. LIW steers had a greater cumulative HH change (p = 0.04). A treatment × day interaction (p = 0.05) was observed for HH with HIW steers having a greater HH at all time points. Final BW and carcass-adjusted (HCW/0.625) BW were greater for HIW steers by 13.1% and 13.4% respectively (p ≤ 0.01). HIW steers had a greater DMI (p = 0.01) compared to LIW. Cumulative ADG was greater for HIW by 3% (p = 0.04). LIW steers had better feed conversion (p = 0.01). HIW steers had greater (p ≤ 0.05) HCW, marbling scores, and yield grade (YG), with decreased REA/HCW (p = 0.01) compared to LIW. The distribution of USDA Yield Grade was altered by initial BW (p = 0.04). No differences were detected (p ≥ 0.22) for the distribution of Quality grade nor liver abscess prevalence and severity. Regression coefficients did not differ between LIW and HIW for urea space calculations of empty body water, fat, or protein (p ≥ 0.70). A quadratic response was noted for empty body fat (EBF), empty body water (EBH20), and carcass protein (CP). In conclusion, HIW steers had greater growth, but poorer feed efficiency compared to LIW steers. Steers with a HIW produced fatter carcasses with a greater degree of marbling.

Supplemental organic trace minerals and a yeast culture product in newly weaned steers: effects of use and delivery method on growth performance and hepatic trace mineral content.

The objective of this study was to determine if supplementation and delivery method of a "stress pack" composed of organic trace minerals and Saccharomyces cerevisiae yeast culture product influenced growth performance, feed efficiency, and hepatic trace mineral concentration in newly weaned steers. Crossbred steers (n = 192; 256 ±â€…14.0 kg) were used in a 49-day receiving phase experiment. Within 36 hours of weaning, steers were weighed, allotted to 24 pens (n = 8 steers/pen; 8 pens/treatment), and randomly assigned to treatments: 1) a traditional receiving diet (CON), 2) a traditional receiving diet plus the "stress-pack" directly in the diet (FORCE), and 3) a traditional receiving diet plus a low-moisture, cooked molasses block fortified with the "stress-pack" (TUB). The "stress-pack" was offered the first 28 day of the 49-day receiving period. Due to adverse weather conditions forecasted on day 1, biopsy samples were collected from a subsample of steers (n = 14 steers) on day 1 to establish hepatic trace mineral concentration baseline. Steers were selected based on the mean body weight (BW) from allotment (day -1) of the pen for collection of subsequent samples (n = 1 steer/pen) on days 14, 28, and 49 for hepatic trace mineral concentration determination. Cumulative dry matter intake (DMI) (P = 0.01) was greater for FORCE compared to CON and TUB. Final BW and average daily gain (ADG) tended (P ≤ 0.10) to be greater for FORCE compared to TUB and CON by 5.4% and 9.4%, respectively. Feed efficiency did not differ between treatments (P = 0.28). A treatment × day interaction (P ≤ 0.01) for hepatic Cu concentration was noted. The FORCE treatment had greater hepatic Cu compared to TUB and CON for the entire period. The steers that received TUB had greater hepatic Cu compared to CON on days 14 and 28, but similar to CON on day 49. The addition of a "stress-pack" to diets offered to newly weaned cattle enhanced hepatic trace mineral concentration, and delivery method influences DMI and daily gain.

Temperature Fluctuations Modulate Molecular Mechanisms in Skeletal Muscle and Influence Growth Potential in Beef Steers.

Our investigation elucidated the effects of severe temperature fluctuations on cellular and physiological responses in beef cattle. Eighteen Red Angus beef steers with an average body weight of 351 ±â€…24.5 kg were divided into three treatment groups: 1) Control (CON), exposed to a temperature-humidity index (THI) of 42 for 6 h without any temperature changes; 2) Transport (TP), subjected to a one-mile trailer trip with a THI of 42 for 6 h; and 3) Temperature swing (TS), exposed to a one-mile trailer trip with a THI shift from 42 to 72-75 for 3 h. Our findings indicate that TS can induce thermal stress in cattle, regardless of whether the overall temperature level is excessively high or not. Behavioral indications of extreme heat stress in the cattle were observed, including extended tongue protrusion, reduced appetite, excessive salivation, and increased respiratory rate. Furthermore, we observed a pronounced overexpression (P < 0.05) of heat shock proteins (HSPs) 20, 27, and 90 in response to the TS treatment in the longissimus muscle (LM). Alterations in signaling pathways associated with skeletal muscle growth were noted, including the upregulation (P < 0.01) of Pax7, Myf5, and myosin heavy chain (MHC) isoforms. In addition, an increase (P < 0.05) in transcription factors associated with adipogenesis was detected (P < 0.05), such as PPARγ, C/EBPα, FAS, and SCD in the TS group, suggesting the potential for adipose tissue accumulation due to temperature fluctuations. Our data illustrated the potential impacts of these temperature fluctuations on the growth of skeletal muscle and adipose tissue in beef cattle.

In this study, we investigated the effects of severe temperature fluctuations on beef cattle and their cellular and physiological responses. Our findings demonstrate that even moderate temperature swings can cause thermal stress in cattle, leading to observable behavioral signs such as extended tongue protrusion, reduced appetite, excessive salivation, and increased respiratory rate. We also observed a significant increase in the expression of heat shock proteins (HSPs), which protect cells from stress, indicating their importance as early responders to temperature fluctuations. Furthermore, we examined the signaling pathways involved in skeletal muscle growth and found that severe temperature fluctuations can stimulate the upregulation of myogenic regulatory factors and myosin heavy chains. These changes suggest an increased demand for muscle contractile properties and hyperplasia during temperature challenges. In addition, our study revealed alterations in transcription factors associated with adipogenesis, such as PPARγ and C/EBPα, indicating the potential for adipose tissue accumulation in response to temperature fluctuations.

Evaluation of a ruminally protected blend of pantothenic acid, pyridoxine, folic acid, biotin, and vitamin B12 on finishing steer growth performance, efficiency of dietary net energy utilization, carcass trait responses, and liver abscess prevalence and severity.

The objective of this study was to determine the influence that a ruminally-protected B-vitamin (RPBV) blend (containing vitamin B5, B6, B7, B9, and B12) 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 ±â€…25.8 kg) from two different sources, were used in a 126-d RCBD experiment. Within 48 h after arrival, steers were individually weighed and allotted to 1 of 24 pens (n = 8 to 12 steers; 8 pens per treatment) and randomly assigned to 1 of 3 treatments: (1) No RPBV; (2) RPBV1 at 1 g/steer d-1; 3) RPBV2 at 2 g/steer d-1. During the first 14 d, cattle received two transition diets with increasing concentrate. From days 15 to 126, cattle were fed the final diet containing 53% dry-rolled corn; 23% corn silage; 20% MDGS; and 4% suspended supplement. On the first 28 d, steers of RPBV1 had a greater average daily gain (ADG) and better feed conversion (G:F), both by 9% (quadratic effect, P ≤ 0.02). However, cumulatively, no differences (P ≥ 0.13) among treatments were found for dry-matter intake (DMI), live final BW, ADG, or G:F. Carcass-adjusted final BW, ADG, and G:F were not influenced by treatment (P ≥ 0.59). Additionally, carcass weight, dressing percentage, marbling score, kidney-pelvic-heart fat, or BW at 28% empty body fat did not differ among treatments (P ≥ 0.11). Ribeye area (REA) was altered (quadratic effect, P = 0.02) by treatment; steers from RPBV1 had decreased REA compared to others. Additionally, calculated yield grade (YG) and calculated retail yield (RY) were altered (quadratic effect, P ≤ 0.01) by treatment; steers from RPBV1 had increased YG and decreased RY compared to others. Estimated empty body fatness tended (P = 0.06) to be greater from steers-fed RPBV compared to 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 treatment differences in liver abscess incidence or severity were observed (P = 0.13). The use of RPBV altered carcass muscularity and rib fat accumulation affecting the overall YG distribution. However, RPBV did not appreciably influence any cumulative growth performance measures or liver abscess outcome.

Longitudinal Assessment of Prevalence and Incidence of Salmonella and Escherichia coli O157 Resistance to Antimicrobials in Feedlot Cattle Sourced and Finished in Two Different Regions of the United States.

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. After determining fecal Salmonella prevalence, heifers were sorted into one of four treatments: heifers originating from South Dakota (SD) and finished in SD (SD-SD); heifers originating from SD and finished in Texas (SD-TX); heifers originating from TX and finished in SD (TX-SD); and heifers originating from TX and finished in TX (TX-TX). Fecal, pen, and water scum line samples were collected longitudinally throughout the study; hide swab and subiliac lymph node (SLN) samples were collected at study end. 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 day (d) 14 through study end, prevalence was greatest for TX-TX and SD-TX heifers compared with SD-SD and TX-SD heifers. 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 that the region of finishing influences pathogenic bacterial shedding patterns, with the initial 14 d after feedlot arrival being critical for pathogen carriage.

Manger space restriction does not negatively impact growth efficiency of feedlot heifers program fed a concentrate-based diet to gain 1.36 kg daily.

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 study. Heifers were received approximately 60 d prior to study initiation. Initial processing (53 d before study initiation) included individual BW, application of an identification tag, vaccination against viral respiratory pathogens and clostridial species, and administration of doramectin pour-on for control of internal and external parasites. All heifers were administered 36 mg of zeranol at study initiation and 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 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 days 1 to 22, 2.00 NEm and 1.35 NEg from days 23 to 82, and 1.97 NEm and 1.32 NEg from days 83 to 109 were used. 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 weight gain within each pen 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 2 weeks compared to the 16IN heifers. These data suggest restricting manger space allocation from 40.6 to 20.3 cm did not negatively influence gain efficiency or the efficiency of dietary net energy utilization in heifers programmed fed a concentrate-based 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 effective means to program cattle to a desired rate of daily gain during the growing phase.

Evaluation of long-term supplementation of a direct-fed microbial and enzymatically hydrolyzed yeast cell culture product on feedlot growth performance, efficiency of dietary net energy utilization, heat stress measures, and carcass characteristics in beef steers.

The objective of this research was to determine the influence of long-term supplementation (258 d) of a direct-fed microbial (DFM) and yeast cell wall (YCW) product used alone or in combination on growth performance, dietary net energy utilization, and carcass characteristics in beef steers finished under climatic conditions in the Northern Plains (NP). Single-sourced Charolais × Red Angus steers [n = 256; body weight = 246 ± 1.68 kg] were blocked by pen location in a 2 × 2 factorial arrangement of DFM and YCW. Steers were administered a series of diets common to the NP and administered ractopamine hydrochloride (RH; 300 mg/kg) during the last 28 d of the finishing phase. Steers were vaccinated and poured at processing and individually weighed on days 1, 14, 42, 77, 105, 133, 161, 182, 230, and 258. Temperature-humidity index (THI) was calculated during RH supplementation. For 98% of the experiment, the THI was lower than 72 and thus cattle were not under high-ambient temperature. On days 1, 2, 21, and 22 of RH supplementation, respiration rates (RR), and panting scores (PS) were determined before and after AM and PM feedings (0700 h, 1100 h, 1400 h, and 1700 h). A DFM + YCW interaction was noted for the proportion of steers categorized as PS 2.0 at 1100 h on day 21 (P = 0.03) and RR on day 21 at 1400 h (P = 0.02). Control steers had a greater proportion of PS 2.0 compared to DFM or YCW steers (P ≤ 0.05), while DFM + YCW steers did not differ from others (P ≥ 0.05); DFM + YCW steers had greater (P < 0.05) RR compared to DFM steers, while control and YCW steers did not differ from others (P ≥ 0.05). No DFM + YCW interactions or main effects (P ≥ 0.05) were observed for cumulative growth performance measures. However, YCW steers had 2% lower (P = 0.04) dry matter intakes compared to steers not fed YCW. No DFM + YCW interactions or main effects (P ≥ 0.05) were observed for carcass traits or liver abscess severity. However, a DFM + YCW interaction (P < 0.05) was noted for the distribution of USDA yield grade (YG) 1 and Prime carcasses. Control steers had a greater proportion (P < 0.05) of YG 1 carcasses compared to other treatments. DFM+YCW steers had a greater proportion (P < 0.05) of USDA Prime carcasses compared to DFM or YCW but were similar to control steers, which were also similar to DFM or YCW. Overall, the use of DFM and YCW alone or in combination had minimal effects on growth performance, carcass traits, and heat stress measures in steers finished in NP climatic conditions.

Evaluation of the effects of corn silage maturity and kernel processing on steer growth performance and carcass traits.

Two experiments were conducted to investigate the effects of feeding kernel processed corn silage to growing calves at 65% inclusion (dry matter [DM] basis; Exp. 1] and finishing beef steers at 20% inclusion (DM basis; Exp. 2). In Exp. 1, steers (n = 184; initial shrunk body weight [BW] = 388 ± 22.3 kg) were used to evaluate the influence that kernel processing of corn silage has on production responses when fed at 65% diet inclusion (DM basis) during a 46-d growing period. Steers were allotted to 1 of 24 pens (12 replicate pens/treatment). Treatments were based upon corn silage that was either kernel processed or not. In Exp. 2, steers (n = 192; initial shrunk BW = 446 ± 28.3 kg) were used in a 112-d finishing experiment. Treatments were grouped in a 2 × 2 factorial arrangement (24 pens total; 8 steers/pen) to evaluate corn silage harvest maturity (1/2 to 2/3 milk line or black layer) and kernel processing (processed or not) at time of corn silage harvest on finishing steer growth performance and carcass traits when corn silage is fed at a dietary DM inclusion of 20%. Both experiments were analyzed as a randomized completed block design with pen as experimental unit. In Exp. 1, final BW tended (P = 0.07) to be increased by 3 kg in kernel processed corn silage. Daily weight gain and DM intake were increased (P ≤ 0.04) by 6% and 2%, respectively, in steers fed kernel processed corn silage compared to controls; however, gain efficiency was not appreciably influenced by treatment (P = 0.15). In Exp. 2, there were no harvest maturity × kernel processing interactions (P ≥ 0.26) for any growth performance measures or any parameters related to efficiency of dietary NE utilization. No harvest maturity × kernel processing interactions (P ≥ 0.08) were observed for any carcass traits except for the distribution of USDA Prime carcasses (P = 0.04). Steers fed 2/3 milk line and unprocessed corn silage had a lower (P = 0.05) proportion of carcasses grade USDA Prime (0.0%) compared to all other treatments (12.0%). Harvest time (P ≥ 0.07) and kernel processing (P ≥ 0.07) of corn silage had no appreciable influence on any other carcass trait measures. These data indicate that kernel processed corn silage fed to growing calves at 65% diet inclusion (DM basis) enhances intake and daily gain, while kernel processed corn silage fed to finishing steers at 20% diet inclusion (DM basis) does not appreciably influence daily gain, efficiency of gain, or carcass parameters.

Kernel processing of corn silage has yielded inconsistent results on diet digestibility and growth performance in beef cattle. These are likely a function of a variety of factors such as differing dry matter concentration of corn silage at harvest, diet inclusion levels, and length of cut. Two experiments were conducted to determine the effect that kernel processing of corn silage has on production responses in growing (65% dietary dry matter inclusion) and finishing beef steers (20% dietary dry matter inclusion). Data from the growing steer experiment when corn silage was included in the diet at 65% (dry matter basis) indicate that kernel processing of corn silage enhances dry matter intake and daily weight gain of beef steers with no appreciable influence on DM conversion efficiency. Data from the finishing steer experiment indicate that harvest maturity and kernel processing of corn silage have minimal effects on animal growth performance and carcass traits in finishing steers when corn silage is fed at 20% inclusion (dry matter basis). Variable responses could be related to differences in inclusion level, differences in effective roughage level fed, and a variety of other factors. Overall, these results suggest that corn silage fed to growing calves should be kernel processed to enhance dry matter intake and daily weight gain, while kernel processed corn silage fed to finishing steers does not appreciably influence daily gain, efficiency of gain, or carcass parameters.

Evaluation of similar dietary roughage equivalency fed to beef steers during the growing and finishing phase.

The objective of this experiment was to determine the influence that similar dietary roughage equivalency offered in a single or two-diet system during a 210-d growing-finishing period has on growth performance, the efficiency of dietary net energy (NE) utilization, and carcass traits in beef steers. Beef steers (n = 46; initial shrunk [4%]; body weight [BW] = 281 ± 40.4 kg) were fed once daily, and bunks were managed according to a slick bunk management system across all 10 pens. Treatments included the following: 1) A single diet program that was formulated to provide 16% (dry matter [DM] basis) dietary roughage equivalency; SD) or 2) multiple diet programs (formulated to provide a dietary roughage equivalency (DM basis) of 25% for 98 d, 16% for 14 d, and 7% for 98 d; MD). Day 1 to 112 was considered the growing period, and day 113 to 210 (the day of harvest) was considered the finishing period, all steers were implanted on day 1 with a 100 mg trenbolone acetate (TBA) and 14 mg estradiol benzoate (EB) implant and implanted with a 200 mg TBA and 28 mg EB implant on day 112. Average daily gain tended (P = 0.06) to be 9.5% greater for SD compared to MD during the growing portion, and average daily gain (ADG) was greater by 11.3% (P = 0.01) for MD compared to SD during the finishing phase of the experiment. Cumulative ADG did not differ (P ≥ 0.86) between treatments (1.61 vs. 1.62 ± 0.046 kg) for SD and MD, respectively. Cumulative dietary NEm and NEg calculated based on performance did not differ (P ≥ 0.96) between treatments. There were no differences (P ≥ 0.18) detected between treatments for hot carcass weight, dressing percent, longissimus muscle area, rib fat, United States Department of Agriculture (USDA) marbling score, kidney, pelvic, heart fat, yield grade, retail yield, empty body fat, or body weight at 28% estimated empty body fat. These data indicate that feedlot producers can feed a single growing-finishing diet to beef steers with minimal effects on overall growth performance or carcass traits.

We aimed to determine the influence of feeding a dietary roughage equivalency in a single or multiple diet system during a 210-d growing-finishing period on growth performance and carcass traits of beef steers. Cumulative average daily gain did not differ between treatments. Also, there were no differences detected between treatments for any carcass traits. Feedlot producers can feed a single "grow-finish" diet to weaned beef steers with minimal effects on overall growth performance or carcass traits. Feeding a single diet during both the growing and finishing phases could be used as a strategy to simplify management by reducing the number of diets fed, or as a way to use ensiled roughages more rapidly to reduce feed-out losses during summer months.

Influence of Maternal Carbohydrate Source (Concentrate-Based vs. Forage-Based) on Growth Performance, Carcass Characteristics, and Meat Quality of Progeny.

The objective of this research was to investigate the influence of maternal prepartum dietary carbohydrate source on growth performance, carcass characteristics, and meat quality of offspring. Angus-based cows were assigned to either a concentrate-based diet or forage-based diet during mid- and late-gestation. A subset of calves was selected for evaluation of progeny performance. Dry matter intake (DMI), body weight (BW), average daily gain (ADG), gain to feed (G:F), and ultrasound measurements (muscle depth, back fat thickness, and intramuscular fat) were assessed during the feeding period. Carcass measurements were recorded, and striploins were collected for Warner-Bratzler shear force (WBSF), trained sensory panel, crude fat determination and fatty acid profile. Maternal dietary treatment did not influence (p > 0.05) offspring BW, DMI, ultrasound measurements, percent moisture, crude fat, WBSF, or consumer sensory responses. The forage treatment tended to have decreased (p = 0.06) 12th rib backfat compared to the concentrate treatment and tended to have lower (p = 0.08) yield grades. The concentrate treatment had increased (p < 0.05) a* and b* values compared to the forage treatment. These data suggest variation in maternal diets applied in this study during mid- and late-gestation has limited influence on progeny performance.

Evaluation of Bacillus subtilis PB6 on feedlot phase growth performance, efficiency of dietary net energy utilization, and fecal and subiliac lymph node Salmonella prevalence in spring placement yearling beef steers fed in southeastern South Dakota,.

Yearling crossbred beef steers [N = 238; initial shrunk body weight (BW) = 402 ± 31.2 kg] were used to investigate the influence of a Bacillus subtilis probiotic on animal growth performance, efficiency of dietary net energy (NE) utilization, carcass characteristics, and fecal and subiliac lymph node Salmonella prevalence during a 140-d finishing period at the Southeast Research Farm in Beresford, SD. Steers were allotted to 1 of 24 pens (N = 9-10 steers/pen) and assigned to 1 of 2 dietary treatments (12 pens/treatment): no probiotic (CON) or 0.5 g/steer/d of a B. subtilis PB6 probiotic (CLOSTAT500, Kemin Industries, Des Moines, IA; CLO). Bunks were managed according to a slick bunk management approach. Fecal samples were collected on study days 1, 28, 56, 112, and 140 from a subsample of steers from each pen (N = 5 steers/pen) via rectal palpation and composited by pen for the determination of Salmonella prevalence using selective enrichment and culture media. Upon harvest, subiliac lymph nodes were obtained from an equal number of steers from each treatment (collected from every other steer) following evisceration and hide removal. Data were analyzed as a randomized complete block design and pen served as the experimental unit; an α of 0.05 determined significance. Live-basis final BW and average daily gain tended (P ≤ 0.06) to be reduced for CLO. No differences were detected (P ≥ 0.11) between treatments for dry matter intake or gain efficiency. Treatment neither altered the efficiency of dietary NE utilization nor calculated dietary NE content based upon observed performance (P ≥ 0.46). No differences were detected between treatments for any carcass traits (P ≥ 0.15). No Salmonella was recovered in any fecal samples collected on study days 1, 28, or 56. On day 112, steers from CLO had a numerically lower (P = 0.17; 25.0 vs. 8.3%) incidence of fecal Salmonella compared to CON. On study day 140, fecal Salmonella incidence did not differ between treatments (P = 0.34; 0.0 vs. 8.3%) for CON and CLO, respectively. Upon harvest, no Salmonella was recovered in any subiliac lymph nodes. These data indicate that B. subtilis PB6 did not influence feedlot phase growth performance or fecal Salmonella prevalence. Additionally, Salmonella was not observed in the subiliac lymph nodes of any steers upon harvest.

Effect of Complete Replacement of Dry-Rolled Corn with Unprocessed Rye on Growth Performance, Efficiency of Dietary Net Energy Use, and Carcass Traits of Finishing Heifers.

Continental crossbred beef heifers were used in a randomized complete block design experiment to evaluate the effects of replacement of dry-rolled corn with unprocessed rye on the finishing-phase growth performance and efficiency of dietary net energy (NE) use. Fifty-six heifers (433 ± 34.0 kg) were transported 241 km from a sale barn in North Central South Dakota to the Ruminant Nutrition Center in Brookings, SD. Heifers were blocked by weight grouping and allotted to treatment pens (n = 7 heifers/pen and 4 pens/treatment). Treatments included a finishing diet that contained 60% grain (diet dry matter basis) as dry-rolled corn (DRC) or unprocessed rye grain (RYE). On study day 14, all 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, USA). The RYE heifers had decreased (p ≤ 0.01) final body weight, average daily gain, and gain efficiency; however, they tended (p = 0.08) to have a greater dry matter intake compared to DRC heifers. RYE heifers 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 heifers. The dressing percentage, 12th rib fat thickness, ribeye area, and the distribution of yield and quality grades were not altered (p ≥ 0.12) by dietary treatment. The hot carcass weight, calculated 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 heifers. 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 the carcass quality grade. 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 (processing index = 78.8%). Rye grain fed as processed or unprocessed grain has an NE value that is less than 90% of that of dry-rolled corn.

Evaluation of hybrid rye on growth performance, carcass traits, and efficiency of net energy utilization in finishing steers.

Crossbred beef steers with a high percentage of Angus ancestry [n = 240, initial shrunk body weight (BW), 404 ± 18.5 kg] were used in a 117-d feedlot experiment to evaluate the effect of hybrid rye (Rye; KWS Cereals USA, LLC, Champaign, IL) as a replacement for dry-rolled corn (DRC) on growth performance, carcass traits, and comparative net energy (NE) value in diets fed to finishing steers. Rye from a single hybrid (KWS Bono) with an ergot alkaloid concentration of 392 ppb was processed with a roller mill to a processing index (PI) of 78.8 ± 2.29. Four treatments were used in a completely randomized design (n = 6 pens/treatment; 10 steers/pen), where DRC (PI = 86.9 ± 4.19) was replaced by varying proportions of Rye [DRC:Rye, dry matter (DM) basis (60:0), (40:20), (20:40), and (0:60)]. Liver abscess scores and carcass characteristics were collected at the abattoir. Carcass-adjusted performance was calculated from hot carcass weight (HCW)/0.625. Performance-adjusted NE was calculated using carcass-adjusted average daily gain (ADG), DM intake (DMI), and mean equivalent shrunk BW with the comparative NE values for rye calculated using the replacement technique. Data were analyzed using the GLIMMIX procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) with pen as the experimental unit. Treatment effects were tested using linear and quadratic contrasts, as well as between diets with and without Rye. Replacing DRC with Rye linearly decreased (P ≤ 0.01) carcass-adjusted final BW, ADG, DMI, and gain:feed (G:F). Feeding rye linearly decreased HCW and longissimus muscle area (P ≤ 0.04). Distributions of liver scores and USDA grades for quality and yield were unaffected by treatment (P ≥ 0.09). Estimated replacement NE for maintenance (NEm) and gain (NEg) values for rye, when included at 60% of diet DM, were 1.90 and 1.25 Mcal/kg, respectively. Rye can be a suitable feed ingredient in finishing diets for feedlot steers. Estimated replacement values of Rye when fed at 60% of diet DM closely agreed with current tabular standards but, when included at 20% of diet DM, estimated NEm and NEg values of Rye were increased 9.5% and 12.8%, respectively. Net energy value of Rye for gain is approximately 84% compared to DRC; thus, the complete replacement of DRC with Rye depressed DMI, ADG, G:F, and carcass weight.

South Dakota State University Beef 2020 increases participant knowledge of the beef industry.

South Dakota State University has developed a hands-on program that addresses the preharvest management factors that influence beef carcass value to aid producers in their management and marketing decisions. The 3-d program includes live cattle and carcass evaluation, beef carcass fabrication, a harvest demonstration, sensory panel, and presentations on topics including live market cattle evaluation, health, and disposition in relation to carcass quality, feeding and management, and value-added beef cuts. To evaluate program effectiveness, data were collected from all programs held between 2013 and 2019. Participants were asked to evaluate their perceived value for each program component, as well as their knowledge of the industry prior to and after completing the program. Upon completion of the 2018 Beef 2020, a focus group of program alumni was assembled to better understand participant experiences, application of the material, and guide future programming. The recommendations of the focus group were implemented during the 2019 program. Component value scores are reported in a box and whisker plot and participant knowledge was evaluated using a paired t-test with significance determined at P < 0.05. Special attention was given to the results of 2019 compared to previous years to determine the efficacy of the program changes. Overall, the average value scores for the sessions all ranked above 8 on a scale of 1-10, indicating a relatively large value to participants. Knowledge of carcass traits, carcass value, and management factors that influence those traits increased after participation in the Beef 2020 program (5.18 vs. 7.67 ± 0.16; P < 0.0001). The use of a focus group was concluded to be an effective means of assessing program value, strengths, and weaknesses. The Beef 2020 program can be used as a model for other Extension professionals to create programs intended to link livestock producers to their end products.

Effect of inclusion rate of silage with or without alpha-amylase trait on finishing steer growth performance, carcass characteristics, and agronomic efficiency measures.

One hundred ninety-two Continental × British steers [initial body weight (BW) = 420 kg (standard deviation = 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 hybrid (Golden Harvest G07B39-311A, Syngenta Seeds LLC, Minnetonka, MN; CON) or a hybrid with increased expression of alpha-amylase (Syngenta Enogen Feed corn, Golden Harvest E107B3-3011A-EVT5, Syngenta Seeds, LLC; ENO) fed at either 12% (12SIL) or 24% (24SIL) of diet dry matter. Steers were blocked by source and location (source 1: first three pen replicates, n = 10 steers per pen with a fourth pen replicate of six steers per pen; source 2: one pen replicate, n = 12 steers per pen) 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 (DOF). There were no silage hybrid by inclusion rate interactions detected for live growth performance (P ≥ 0.15). Silage hybrid did not affect 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 increased G:F (P = 0.01) but increased FBW (P = 0.02) because of greater DOF compared with 12SIL. A hybrid by inclusion rate interaction was detected (P = 0.04) for calculated yield grade (YG) with steers fed 24SIL having increased YG within CON but not ENO. Hot carcass weight and rib fat were unaffected by silage hybrid (P ≥ 0.81) but were increased by feeding 24SIL (P = 0.03 and P = 0.02, respectively). Feeding increased amounts of silage increased beef produced per hectare (P = 0.05). Source of silage did not affect feedlot growth performance of cattle but, because of slight differences in estimated silage yield, conventional silage produced more kilograms of beef per hectare (P < 0.01). Feeding increased amounts of silage reduced G:F on both a live and carcass-adjusted basis but increased kilograms of beef produced per unit of land, which is paramount to cattle feeders who grow their own feedstuffs.