Objective: Evaluate the effects of the maternal bovine appeasing substance (mBAS) on feedlot performance, health outcomes, hair cortisol concentrations, and carcass characteristics for northern US-origin yearling beef steers. Materials and Methods: Crossbred steers (n = 1,754; initial BW = 424 kg, SD = 25 kg) were received on 7 arrival dates to a commercial Nebraska feedyard, gate sorted into 20 pens, and pens were randomly assigned to receive (1) 10 mL of mBAS (FerAppease, FERA Diagnostics and Biologicals) or (2) 10 mL of mineral oil placebo (CON). Treatments were applied topically to the poll and muzzle (5 mL at each site) at initial processing and reimplant. A subset of 5 steers per pen (n = 100) were randomly selected for hair sampling at arrival and d 14 to assess cortisol. Steers were fed a high-moisture, corn-based finishing diet for 167 d on feed before harvest. Results and Discussion: Dry matter intake and ADG did not differ between treatments. Carcass-adjusted G:F tended to improve for mBAS on a deads-in basis. Hot carcass weight, LM area, and marbling score were similar, though dressing percent tended to be greater with mBAS. Quality grade and yield grade distributions did not differ between treatments. Administering mBAS did not affect treatment frequency for illness, overall mortality rate, or hair cortisol concentrations. Implications and Applications: Topical mBAS application at arrival and reimplant did not influence growth, health, or cortisol, but may modestly improve carcass-adfeed in steers.

Abstract The objectives of this experiment were to evaluate the value of palm oils as ingredients in cattle feed compared to no fat or tallow on beef (steak) quality measures. Steers (n = 430; 472 kg; SD = 22) were allocated to 40 pens in a generalized randomized block design consisting of 3 blocks where steers were blocked by weight. Steers were then assigned to 1 of 5 dietary treatments consisting of different sources of fat supplemented at 3.5% of the diet DM: 1) No oil; negative control containing 0% supplemental fat, 2) Tallow; positive control, 3) Crude palm oil, 4) Refined, bleached, and de-odorized palm olein oil, [RBD olein] and 5) Crude, high oleic, palm oil, [crude HOPO]. Cattle were fed for a total of 160 days, and due to a delay in obtaining the palm oils from Colombia, cattle received treatments for the last 107 days before slaughter. Forty-eight h post-harvest, 3 beef strip loins were collected from each pen, individually vacuum packaged, aged for 14 d, and frozen until analysis. Color of subcutaneous fat was measured in which lightness (L*) and redness (a*) were not different among the treatments (P > 0.68). Yellowness (b*) was significantly higher for the crude palm (12.9) and crude HOPO (14.2) treatments (P ≤ 0.02). After a 72 h thawing period, loins were cut into 2.54 cm strip steaks, which were used for further analysis. Retail display color was measured over a 7 d period and there were no differences observed in any color metrics across treatments (P ≥ 0.55). Furthermore, no differences were observed in lipid oxidation between treatments (P = 0.17). Moisture and total ether extractable lipid of steaks were not different between treatments (P ≥ 0.85). Fatty acid composition of steaks, trimmed of subcutaneous fat, did not differ among treatments, except for arachidonic acid, which was greater in steaks from cattle fed RBD olein (P = 0.02). After cooking each steak to an internal temperature of 71º C, tenderness was assessed using the slice shear force and Warner-Bratzler shear force tests. While steaks from all treatments were considered “very tender”, there was a tendency for tallow and RBD olein to decrease steak tenderness. Steaks from cattle fed tallow and RBD olein had slightly greater Warner-Bratzler shear force values (2.83 and 2.79 kg, respectively) compared with those from cattle fed no supplemental fat (2.54 kg; P = 0.10). Similarly, slice shear force values were greater for tallow (19.2 kg) and RBD olein (18.8 kg) compared with no added fat (16.7 kg; P = 0.15). These data suggest that adding fractions of palm oil at 3.5% of diet DM does not negatively affect meat quality relative to tallow.

Abstract Distillers grains plus solubles (DGS) is commonly fed to growing and finishing cattle, where it provides both energy and protein. Historically valued as a protein source due to limited quantities, DGS gained prominence in the early 2000s with the expansion of the ethanol industry, shifting its use towards displacing dietary energy, primarily from corn, in feedlot diets. Distillers grains from the traditional process contained 30-33% protein, 33-36% neutral detergent fiber and 12-13% fat. Beginning in 2012, ethanol plants began extracting a portion of oil during processing, reducing its fat content to 8-9%. An analysis was conducted to determine the feeding value of full-fat and de-oiled DGS relative to a corn control and to quantify the impacts on dry matter intake (DMI) and average daily gain (ADG). This dataset included 50 experiments with over 6,100 head of finishing cattle conducted at the University of Nebraska from 1993 to 2023. This analysis was limited to experiments that displaced dry-rolled corn, high-moisture corn or a combination of the two, and containing 15% or more DGS. Data were analyzed using the MIXED procedure of SAS with distillers type (dried, modified, or wet DGS), fat content (full fat or de-oiled), and the interaction between DGS type and fat content included in the model. Distillers grains type had a significant impact on the percentage change in DMI compared to the corn control (P < 0.01), whereas fat content had no effect (P = 0.13). Feeding dried and modified DGS increased DMI by 6.0 and 3.4%, respectively, relative to the control. There was a tendency for an interaction between DGS type and fat content for improvements in ADG (P = 0.09). Feeding full-fat dried and wet DGS resulted in a greater improvement in ADG compared to their de-oiled form. However, for modified DGS the de-oiled form had a greater improvement in ADG compared to its full-fat form, which could be due to a greater increase in DMI when fed in the de-oiled form. Regardless of DGS type or fat content, feeding DGS improved ADG by 8% compared to the corn control. Both DGS type and fat content significantly influenced feeding value (P ≤ 0.03). For dried, modified, and wet DGS, the feeding value was 113.4%, 119.5%, and 129.3% when fed in the full-fat form and 103.4%, 114.7%, and 120.4% when fed in the de-oiled form. On average, partial fat removal, lowered the feeding value of DGS by 8 percentage units from 120.7% to 112.8% across all DGS types. Despite this reduction in the feeding value, de-oiled DGS increased ADG relative to the corn control. The improvement in feeding value for wet and modified DGS illustrates that feeding DGS provides both protein and energy for finishing cattle.

Abstract A finishing study was conducted to evaluate feeding whole (WSB) or roasted (RSB) soybeans at 12 or 16% of diet DM compared to feeding 9% soybean meal (SBM), 16% wet distillers grains (WDGS), or a corn control with urea (CON). Crossbred yearling steers (n = 504; initial BW = 422 kg) were utilized in a generalized randomized block design with 8 pens per treatment and 9 steers per pen. Cattle performance has been reported but feeding roasted soybeans resulted in improved gain and G:F compared to whole soybeans which were better than all other treatments. Dietary fat was 3.0, 2.9, and 3.9% for CON, SBM, and WDGS treatments which increased to 5.4% with 12% of either WSB or RSB and was increased further to 6.2% fat when 16% of either soybean treatment was fed. The objective of this study was to determine the impact of feeding different amounts and sources of fat on diet and fat digestibility. To determine fecal output, 2.5% zeolite clay was fed for 5 days prior to 3 days of pen surface fecal collections. Acid detergent insoluble ash (ADIA) was used as a marker and the zeolity clay was 86.4% ADIA. Dietary ingredients and fecal samples were composited by day and pen, and analyzed for ADIA, OM, and fat. Treatments were evaluated using proc mixed as both an unstructured treatment design using a protected F-test and the 2 × 2 factorial of either 12 or 16% inclusion of either WSB or RSB were tested. Digestibility of DM and fat were impacted by dietary treatment (P < 0.01). Cattle fed CON and WDGS were similar (P = 0.16) in DM digestibility but lower (P < 0.03) than cattle fed any of the soy treatments (SBM, WSB, or RSB). Fat digestibility was similar (P = 0.79) between CON (89.5%) and SBM (89.3%) but lower (P < 0.07) than cattle fed WDGS (92.1%), 12% WSB (91.8%), 16% WSB (92.6%), or 16% RSB (91.4%). Cattle fed 12% RSB were intermediate for fat digestibility (90.4%). For the factorial, no interaction was observed for fat digestibility (P = 0.88). Feeding 12 or 16% whole or roasted soybeans did not impact fat digestion (P = 0.21). Roasting soybeans tended to slightly reduce fat digestibility (P = 0.07) from 92.2% to 90.9%. In this study, feeding more fat in the diets with either whole or roasted soybeans did not decrease fat digestibility, but fat excretion did increase as fat intake increased.

Abstract Exploring how residual methane production (RMP) relates to productivity may reveal opportunities for selecting animals with lower methane emissions without impacting performance. This trial aimed to evaluate differences in average daily gain (ADG), dry matter intake (DMI), feed efficiency, body composition and gaseous exchange in growing beef heifers with divergent phenotypes for RMP. Growing beef heifers (n = 97; initial BW = 264 ± 25 kg) with high genetic variability were assigned randomly to one of two blocks. Both blocks were evaluated during an 84-day feed efficiency test using individual feed bunks (American Calan Inc.), during which time individual DMI and BW were recorded to determine ADG and feed efficiency. Carcass ultrasound data were collected at the end of the study. Each animal also participated in an energy metabolism study, that included four consecutive days of total fecal and urine collections and one day of methane (CH4), carbon dioxide (CO2), and oxygen (O2) exchange measurements using headboxes (HB) through an indirect calorimetry method. All heifers were fed a common diet of 80% corn silage, 15% dried distillers grains, and 5% supplement (DM basis), offered ad libitum. Residual methane production was calculated within block from the regression of CH4 on metabolic body weight (MBW) and DMI measured while heifers were in the HB. Heifers were divided into one of three RMP classes (± 0.5 SD from the mean block RMP). Data were analyzed using a mixed model including RMP classification and block as fixed effects. Low RMP heifers emitted 27.8% less CH4 (g/d; P < 0.001) and 32.3% less CH4 yield (g/kg DMI; P < 0.001). Similarly, compared to high RMP heifers, low RMP heifers produced 10.4% less CO2 (g/d; P = 0.033) and consumed 11.6% less O2 (g/d; P = 0.011). During the feed efficiency test, there were no differences in initial and ending BW, ADG, DMI, gain-to-feed ratio, longissimus muscle area or intramuscular fat (P > 0.399) between heifers with high and low RMP phenotypes. In terms of metabolism traits, there were no differences for MBW, DMI, or dry matter digestibility (P > 0.691) between heifers with divergent RMP phenotypes. Using Pearson’s correlations, DMI during the feed efficiency test was positively associated with ADG (r = 0.55; P < 0.001) and DMI measured in the headbox was positively associated with CH4 production (r = 0.66; P < 0.001), highlighting the role of feed intake in growth and CH4 emissions. Gain (r = 0.16; P = 0.128) and feed efficiency (r = -0.04; P = 0.674) were not associated with RMP; however, low RMP heifers emitted 27.8% less methane (g/d). These results suggest that selecting for reduced RMP could lower methane emissions without impacting productivity.

Abstract The Timmerman Feedyard Management Internship began in 1988 under the direction of Dr. Terry Klopfenstein. It is a nationally renowned feedyard management training program, exclusive to University of Nebraska-Lincoln. The internship trains students through comprehensive feedyard management classes and with real world experiences in high caliber feedyards. The program is designed for students interested in pursuing a career in beef feedyard management or other related agribusiness areas. The purpose of the internship is to train undergraduate students in feedyard management to fill the growing need for trained responsible individuals who can fill management positions in feedyards. The internship is divided into three segments. The pre-internship session occurs on the University of Nebraska-Lincoln campus beginning near the end of May to provide basic knowledge pertaining to the feedyard industry. Students interact with specialists in feedyard management and nutrition, animal health, economics, and personnel management. The second portion of the internship occurs when students go to their host feedyards to experience firsthand how professionals utilize the principles students learned in the pre-session. During the third portion, students return to Nebraska for two weeks to discuss their experiences with each other and the experts they were exposed to during the pre-session. There is no direct cost to the student to participate in the internship, with tuition paid by the Nebraska Cattlemen and from the Timmerman Endowment Fund. The internship is designed students to enter upon or near the completion of their undergraduate degree in Animal Science, Agribusiness, or a related major. The program has trained over 100 interns, many of whom are working in the beef industry today.

Abstract Managing bunks correctly is critical for maximizing feedlot performance. Feedlots primarily use either an ad-libitum system where cattle have the full 24 h to consume feed, or a slick bunk system where a specific feed access time is targeted for cattle to finish their feed prior to the next day’s feeding. A finishing experiment was conducted to evaluate the effects of feed access time on feedlot performance, feeding behavior, ruminal pH and carcass characteristics in yearling heifers. Heifers (n = 234; initial BW = 447 kg, SD = 36 kg) were fed in a randomized complete block design and blocked by body weight into eight pens, each equipped with five electronic feed bunks (Insentec Roughage Intake Control System, Hokofarm Group). Heifers were assigned randomly to one of five feed bunks within each pen, and bunks were assigned randomly to one of five treatments. Treatments were based on access time to feed, either 12, 15, 18, 21, or 24 h of access to feed beginning at 0830 each day. All heifers were fed a common step-up and finishing diet and individual animal dry matter intake and feeding behavior were collected for 104 days. A subset of heifers (n = 16) from the same pen received pH boluses (Moonsyst International) on d 0 (n = 3-4 boluses/treatment). Data were analyzed using a mixed model including treatment and pen as fixed effects. Orthogonal contrasts were used to test linear, quadratic and cubic effects of feed bunk access time. There were no differences in carcass adjusted final BW, ADG, or G:F (P ≥ 0.11). As feed access time increased, dry matter intake increased linearly (P < 0.01). The DMI of heifers allowed 24 h was 4.9% greater than 12 h, but not different compared to 15, 18, or 21 h treatments. The day-to-day variation (CV) of DMI (P = 0.02) and the incidence of liver abscesses (P = 0.03) increased linearly as feed access time increased. As access time to feed increased from 12-h to 24-h, bunk visit duration, and the day-to-day variation of bunk visit duration increased linearly (P < 0.01), and a linear decrease was observed in eating rate as g DMI/min (P < 0.01) with heifers having 12 h access time eating 14% faster compared to heifers having 24 h of feed access. As access time to feed increased, the magnitude of ruminal pH change within a day decreased linearly (P < 0.01), as cattle having less feed access time exhibited a greater intraday pH change. Feed access time greater than or equal to 15 h did not negatively impact DMI, ADG or HCW as cattle modified their behavior based on the feed access time available to them.

Objective: The objective of this experiment was to examine the long-term effects of distillers grain supplementation and nitrogen (N) fertilization on animal performance to determine whether cattle supplemented with dry distillers grains plus solubles (DDGS) can be stocked at the same rate as nonsupplemented cattle on N-fertilized smooth bromegrass pastures. Materials and Methods: Each year, 45 steer calves weighing 321 +/- 27 kg were assigned to 1 of 3 treatments. Treatments consisted of (1) steers grazing nonfertilized smooth bromegrass pastures supplemented with DDGS at 0.6% of BW (DM basis; SUPP); (2) steers grazing smooth bromegrass pastures fertilized with 90 kg of N/ha (FERT); or (3) steers grazing unfertilized smooth bromegrass pastures without DDGS supplementation (CONT). Pasture was the experimental unit, with 3 replications per treatment each year, and pastures were rotationally grazed during the grazing season. The CONT treatment pastures were 30% larger than the SUPP and FERT pastures, based on previous research indicating that nonfertilized pastures produced similar to 70% as much forage as fertilized pastures. Results and Discussion: Across the 17 yr, cattle on the SUPP treatment had greater ADG (1.03 kg) than those on CONT (0.73 kg) and FERT treatments (0.73 kg), which were similar to one another. Similar ADG between the CONT and FERT demonstrate that forage availability was the same and appropriate pasture sizes were used. Body weight gain per hectare was greatest for the SUPP treatment (378 kg/ha), intermediate for the FERT treatment (271 kg/ha), and least for the CONT treatment (186 kg/ha). Implications and Applications: Pasture use efficiency is increased through DDGS supplementation or fertilization of pastures, with the SUPP treatment being the most productive per hectare. Responses vary across years due to precipitation and pasture performance.

Abstract A feedlot finishing experiment was conducted to evaluate the impact of feeding Lubabegron (LUB; Experior; Elanco Animal Health; Greenfield, IN) or Ractopamine Hydrochloride (RAC; Optaflexx; Elanco Animal Health; Greenfield, IN) on feedlot performance, carcass characteristics, and meat quality attributes. Crossbred steers (n = 621; initial BW = 308 kg; SD = 16.1 kg) were utilized in a generalized randomized block design. Treatments included (1) feeding RAC at 300 mg/steer daily for 34-d (plus 2-d withdrawal prior to harvest) or (2) feeding LUB at 36 mg/steer daily for 42-d (plus 4-d withdrawal). Steers were blocked by arrival date at feedlot entry and a health monitoring treatment, and pens were assigned randomly to the two treatments within block. Cattle were weighed on the day that block one received LUB (on d 133), with a 4% shrink applied, and no initial weight differences were observed between treatments (P = 0.89). Performance data represent the entire feeding period. Steers fed LUB exhibited greater average daily gain, a 5% improvement in feed efficiency, and 10 kg heavier carcass weight (P < 0.01). Steers fed LUB had larger ribeye area (P < 0.01), similar 12th rib fat thickness (P = 0.73), and lower marbling score (P < 0.01) compared to steers fed RAC. Quality grade distribution differed (P = 0.02), with RAC-fed steers producing a greater proportion of Prime and upper two-thirds Choice carcasses and fewer low Choice or select carcasses compared with LUB. A subset of 160 USDA Choice strip loins (four per pen) were collected to evaluate meat quality. Steers fed RAC were more tender, particularly at 7-d postmortem (P < 0.01), with a significant treatment x aging interaction (P < 0.01). Cooking loss did not differ between treatments or aging period (7 vs. 21 d). Lightness (L*) was unaffected by treatment, however, RAC-fed steers produced steaks with greater redness (a*; P < 0.01) and yellowness (b*; P = 0.03). Overall, feeding LUB to beef steers increased carcass weight but reduced marbling and slightly reduced tenderness compared to RAC.

Abstract The objective of this experiment was to evaluate the value of palm oil as an ingredient in cattle feed compared to no fat or tallow on performance and carcass characteristics. Steers (n = 430; 472 kg; SD = 22) were allocated to 40 pens in a generalized randomized block design consisting of 3 blocks where steers were blocked by weight and assigned randomly to pens. Pens were assigned randomly to 1 of 5 dietary treatments consisting of different sources of fat supplemented at 3.5% of the diet DM: 1) No oil; negative control containing 0% supplemental fat, 2) Tallow; positive control, 3) Crude palm oil, 4) Refined, bleached, and de-odorized palm olein oil, [RBD olein] and 5) Crude, high oleic, palm oil, [crude HOPO]. Cattle were fed for a total of 160 days, and due to a delay in obtaining the palm oils from Colombia, cattle received treatments for the last 107 days before slaughter. Performance is calculated using the last 107 days of the feeding period. Dry matter intake of cattle was not different among any of the treatments (P = 0.51). All diets containing supplemental fat had numerically greater ADG and final body weights; however, there were no significant differences among any of the treatments (P > 0.39). Due to numerical changes in both intake and gain, differences in G:F due to dietary treatment were observed (P = 0.01). Cattle fed diets containing supplemental fat had greater G:F than those fed no supplemental fat (P = 0.01). Feeding cattle crude palm resulted in greater G:F (0.169) than cattle fed RBD olein (0.164; P = 0.06), while steers fed tallow (0.167) and crude HOPO (0.165) were intermediate (P > 0.15). There were no differences in carcass weight, marbling score, or ribeye area due to treatment (P > 0.30). The results of this study indicate that feeding palm oil products as a source of supplemental fat in finishing diets is comparable to feeding tallow, as cattle fed diets containing supplemental fat experienced improvements in feed efficiency. Feeding crude palm oil resulted in the greatest percent improvement in feed efficiency over the control diet (7.0%) while RBD olein had the lowest percent improvement (3.8%), with crude HOPO (4.4%) and tallow (5.7%) being intermediate. While palm oil sources may differ slightly in their dietary energy content, all palm oil treatments improved feed efficiency over the negative control and are comparable to tallow.

Abstract A receiving study was conducted to evaluate the effectiveness of a remote sensing ear tag (HerdDogg, Seward, NE) on the detection of morbidity, receiving calf performance, and finishing performance. Crossbred steers (n = 638; initial BW = 270 kg; SD = 18.6) were utilized in a generalized randomized block design. Steers were weighed on arrival to establish initial BW. Steers were assigned to one of two treatments based on their arrival date. Two experimental treatment strategies were used to determine steer morbidity: 1) pen-riders evaluated the cattle and made the decision on when to treat (PR) compared to the remote sensing tag that solely identified and flagged cattle in need of treatment (RST). Steers were weighed on arrival to establish initial BW. Steers were assigned to one of two treatments based on their arrival date. The receiving trial lasted 35 days with 6 days of limit feeding followed by 2 consecutive d weights to determine the ending BW. No differences were observed between PR or RST for ending BW, average daily gain (ADG), dry matter intake (DMI), or feed efficiency (P > 0.53) during receiving. A greater proportion of steers assigned to RST were treated compared to PR (42.2% vs. 31.7%, respectively; P = 0.01). Similarly, a greater percentage of RST steers were treated two or more times compared to PR (10.1% vs. 4.5%, respectively; P = 0.01), and tended to have more treated three times (P = 0.10). The average temperature at the first treatment was similar across treatments (P = 0.95), suggesting treated cattle were sick. Following the receiving phase, steers were finished by feeding 180 d. No differences were observed in final BW, DMI, ADG, feed efficiency, 12th rib fat thickness, and hot carcass weight (P > 0.36). The proportion of steers treated two or more times (18.8% vs. 9.4%; P < 0.01) and three or more times (13.4% vs. 2.8%; P < 0.01) was greater for the RST treatment compared to the PR treatment, while the proportion treated at least once (P = 0.18) and the average temperature at the first treatment did not differ (P = 0.59). These results indicate that the remote sensing ear tag increased the rate at which cattle were pulled for treatment but did not influence overall performance or carcass characteristics.

Abstract Inconsistencies in distillers grains deliveries have complicated cattle feeding for feedlot producers and have required diet adjustments during the feeding period. The objective of this study was to determine how the frequency of changing inclusions of modified distillers grains plus solubles (MDGS) throughout the feeding period impacts feedlot cattle performance, carcass characteristics, feeding behavior, and ruminal pH. Steers (n = 229; initial BW = 426 ± 22 kg) were blocked by body weight into one of eight pens, each equipped with five electronic feed bunks (RIC2Discover system; Hokofarm). Treatments for this study included 1) a corn control, 2) 25% MDGS kept at a constant inclusion, and 25% MDGS varying from 15 to 35% on a 3) daily, 4) weekly, or 5) monthly basis. Individual animal dry matter intake (DMI) and feeding behavior data were collected for 131 days during the finishing period. Ruminal pH was evaluated on a subset of steers in one pen (n = 16) for the control, constant, and daily treatments. Data were analyzed using the MIXED procedure of SAS, with treatment and block as fixed effects. Significance was set at P ≤ 0.10. The inclusion of MDGS improved average daily gain (ADG; P ≤ 0.02) and hot carcass weight (HCW; P ≤ 0.06) compared to the control. Cattle fed MDGS constantly had greater ADG compared to weekly variation in MDGS. The HCW for control, constant, daily, weekly, and monthly were 412, 426, 422, 419 and 420 kg, respectively. There was no difference between treatments for DMI (P = 0.42). Cattle fed the control had the lowest G:F and cattle fed constant MDGS had the greatest G:F (P ≤ 0.05), with cattle fed the variable treatments being intermediate. There were no differences between treatments for carcass characteristics (P ≥ 0.12). Dietary treatment impacted the incidence of liver abscesses (P = 0.07), with cattle fed the corn control having the greatest and cattle fed any of the MDGS treatments having lower incidences. For feeding behavior, there were no differences between treatments in number of bunk visits or time spent at the bunk each day (P ≥ 0.19). The day-to-day variation in DMI differed between treatments (P = 0.02), with the control and daily cattle having the highest variation in DMI across days. For the control, constant and daily treatments ruminal pH was 5.87, 6.10 and 6.08, respectively, with the corn control having the lowest pH (P < 0.07) compared to constant and daily. Results suggest that varying MDGS had little impact on cattle performance and feeding behavior, and varying weekly had the largest impact on feedlot cattle when compared to daily or monthly variation. However, including MDGS in the diet was beneficial to just feeding corn.

Abstract The primary reason livers are condemned is due to abscesses, which are visible lesions detected on the liver during routine harvest of the animal. Condemned livers are deemed not fit for human consumption, and result in over $15M in lost income to the U.S. beef industry each year. Liver scoring is a 4-level measurement of abscess severity: 0 (no abscesses), A- (mild: 1-2 small abscesses), A (moderate: 2-4 active abscesses) and A+ (severe: 1 or more large, active abscesses). We quantified the degree to which known sources of variation, including genomic differences among animals, contribute to the incidence of liver abscesses in 1747 feedlot cattle fed a range of diets. Diets were grouped based on corn type (dry-rolled corn (DRC), high-moisture corn (HMC), DRC/HMC or steam-flaked Corn (SFC)) and byproduct (none, modified distillers grains plus solubles (MDGS), and Sweet Bran fed at 20%, 35% or 40%). A common set of SNP (n= 44,666) from the Illumina BovineSNP50 v2 and GGP Bovine 100K were used for genomic analyses. The posterior mean (posterior standard deviation) heritability estimate of liver score was 0.10 (0.05). Within-diet heritability estimates were not significantly different from zero but ranged from 0.02 (0.02) (MDGS) to 0.29 (0.32) (Sweet Bran fed at 35%). A BayesB Genome Wide Association Study with showed that liver score is a very polygenic trait with no large QTL segregating in this population. The genetic and phenotypic correlations of liver score with hot carcass weight, 12th rib fat, longissimus muscle area, or marbling score were not significantly different from zero. Results from the current study show that genomic selection for reduced liver score could be a useful tool to reduce the occurrence of liver abscesses in feedlot cattle, alongside current mitigation strategies; however, more data is needed to gain a better understanding of the genetic basis of liver score, as well as the relationship between liver score and other economically relevant traits, and potential genetic x diet interactions.

Solbran (ICM, Colwich, KS) is new corn byproduct of ethanol production composed of fiber plus condensed distillers solubles and can be fed dry (Dry Solbran; NDF= 41.1%; CP= 21.84%; Ether extract= 8.4%), or wet (Wet Solbran; NDF= 49.7%; CP= 22.67%; Ether extract= 8.5%). The objective of this study was to evaluate the effect of inclusion of distillers grains types on performance, methane, and carbon dioxide production of feedlot cattle, compared to feeding corn to finishing cattle. The treatments included a control (CON) with no distillers grains compared to the inclusion of 40% of dry distillers grains plus solubles (DDGS), wet distillers grains plus solubles (WDGS), Dry Solbran and Wet Solbran. To evaluate CO2 and CH4 production, four paired replicates (4 control and 4 paired pen distillers treatments) were monitored for 16 consecutive weeks using the pen scale emissions barn. Data were analyzed using the MIXED procedure of SAS, the pen was considered as the experimental unit and the block was considered as a fixed effect. Additionally, interactions among moisture (dry and wet) and processing method (Solbran or traditional) were evaluated as a 2 × 2 factorial without CON. For enteric methane data, the control treatment was used as a covariate, and data were analyzed as a 2×2 factorial, where the factors were processing method (Solbran or Traditional), moisture (dry and wet). There was an increase in DMI by adding DDGS, Dry Solbran, and Wet Solbran (P < 0.01) compared to WDGS and CON. There was an increase in ADG by adding DDGS, Dry Solbran, Wet Solbran and WDGS (P < 0.01) compared to CON. These changes in DMI and ADG resulted in increased G:F when WDGS was fed (P < 0.01), a decrease when Dry Solbran (P < 0.01) or DDGS (P < 0.07) were fed, but no difference when Wet Solbran (P = 0.78) were fed compared to the CON. For 2 × 2 factorial, there were no interactions (P > 0.18) except for LM area. The inclusion of wet byproduct increased G:F (P < 0.01) compared to dry, and the traditional processing method had greater G:F (P < 0.01) compared to traditional. There was an increase of 19,6% (P < 0.01) in methane production per steer as g/d and g/kg of DMI for steers fed fractionated distillers grains (Dry and Wet SOLBRAN) compared to steers fed the corn control diet. Steers fed conventional DDGS and WDGS produced similar amounts of methane as the corn control and to one another in g/d and g/kg of DMI (P > 0.26). There was no difference in CO2 production in g/d or g/lb of DMI (P > 0.48). Feeding cattle fractionated distillers grains increased CH4 production but did not affect CO2 production.

A feedlot study was conducted to evaluate the effects of using whole (WSB) or roasted (RSB) soybeans at two inclusion rates (12% and 16% of diet dry matter), soybean meal (SBM), distillers grains (WDGS), or a dry-rolled corn with 1% urea control (CON) in finishing cattle diets on performance and carcass characteristics. Crossbred steers (n=504, initial BW = 423kg ±1.3kg) were utilized in a generalized, randomized block design with 9 steers per pen and 8 replications per treatment, with 7 treatment diets. Cattle were stepped onto their respective finishing diets together utilizing a 21-day step-up period. Cattle were fed treatment diets for 119 d (heavy block) or 160 d (light and medium blocks). Performance and carcass data were analyzed using the MIXED procedure of SAS and analyzed with pen as the experimental unit and block as a fixed effect. A 2x2 factorial analysis using the PROC MIXED procedure in SAS evaluated soybean roasting and inclusion level with potential interactions. Liver abscesses were analyzed as a binomial distribution using the PROC GLIMMIX procedure of SAS. Cattle fed SBM, WDGS, and both RSB diets had greater DMI (P < 0.01) than the 16% WSB, which was not different than the control and 12% WSB diets. Cattle fed the 16% RSB diet had the greatest ADG at 1.90 kg/d, which was greater than (P < 0.01) the CON, SBM, WDGS, and 16% WSB diets. Steers fed the CON and WDGS diets had greater (P < 0.01) G:F compared to the 16% RSB inclusion. Feeding the 16% inclusion of RSB resulted in a greater HCW (P < 0.01) and 12th rib fat thickness (P = 0.01) compared to the CON, WDGS, and 16% WSB diets. For the factorial arrangement of treatments evaluating roasting and inclusion levels effects of soybeans, interactions were observed for DMI and G:F (P < 0.05) suggesting that roasting impacts the performance of cattle and this response is dependent on dietary inclusion. Steers fed 16% WSB had numerically greater G:F compared to 12% inclusion whereas steers fed RSB had also a numerically improved G:F (P = 0.32) by 6.5% when fed 16% compared to 12%. Cattle fed RSB had greater HCW, carcass-adjusted final BW, and ADG (P < 0.01) compared to steers fed WSB. The interaction for HCW and final BW tended to be significant (P = 0.07) as weight tended to increase with inclusion of RSB but tended to decrease when the inclusion of WSB increased. These results suggest soybeans may be used in finishing feedlot diets without reducing cattle performance.

The primary reason livers are condemned is due to abscesses, which are visible lesions detected on the liver during routine harvest of the animal. Condemned livers are deemed not fit for human consumption, and result in over $15M in lost income to the U.S. beef industry each year. Liver scoring is a 4-level measurement of abscess severity: 0 (no abscesses), A- (mild: 1 to 2 small abscesses), A (moderate: 2 to 4 active abscesses), and A+ (severe: 1 or more large, active abscesses). We quantified the degree to which known sources of variation, including genomic differences among animals, contribute to the incidence of liver abscesses in 1,747 feedlot cattle fed a range of diets. Diets were grouped based on corn type (dry-rolled corn [DRC], high-moisture corn [HMC], DRC/HMC or steam-flaked corn [SFC]) and byproduct (none, modified distillers grains plus solubles [MDGS], and Sweet Bran fed at 20%, 35%, or 40%). A common set of SNP (n = 44,666) from the Illumina BovineSNP50 v2 and GGP Bovine 100K were used for genomic analyses. The posterior mean (posterior standard deviation) heritability estimate of liver score was 0.10 (0.05). Within-diet heritability estimates were not significantly different from zero but ranged from 0.02 (0.02) (MDGS) to 0.29 (0.32) (Sweet Bran fed at 35%). A BayesB Genome-Wide Association Study (GWAS) with showed that liver score is a very polygenic trait with no large effect quantitative trait loci (QTL) segregating in this population. The genetic and phenotypic correlations of liver score with hot carcass weight, 12th rib fat, longissimus muscle area, or marbling score were not significantly different from zero. Results from the current study show that genomic selection for reduced liver score could be a useful tool to reduce the occurrence of liver abscesses in feedlot cattle, alongside current mitigation strategies; however, more data are needed to gain a better understanding of the genetic basis of liver score, as well as the relationship between liver score and other economically relevant traits, and potential genetic × diet interactions.

Objectives: The objective of this study was to evaluate the effects of urea and wet distillers grains with solubles (WDGS) inclusion on heifer growth performance and carcass characteristics. Materials and Methods: Crossbred heifers (n = 96) were used to study the effects of 2 inclusion levels of both WDGS and urea in a finishing diet based on dry-rolled corn on performance and carcass characteristics. Heifers were individually fed using a Calan gate system with a 2 x 2 factorial arrangement of treatments. Factors were inclusion of WDGS at either 10% or 20% of diet DM and dietary urea at a concentration of either 0.2% or 1.2% DM basis. Cattle were stratified by BW and assigned randomly to treatment. Blood samples were collected at 3 time points during the feeding period and analyzed for plasma urea nitrogen content. The statistical model included urea and WDGS inclusions and their interactions as fixed effects. Results and Discussion: There were no interactions between WDGS and urea inclusion for any performance or carcass characteristics, so only main effects are discussed. There were no differences for final BW, ADG, and G:F on a live or carcass-adjusted basis for either urea or WDGS inclusion in the diet. Dry matter intake was less with increased urea inclusion; however, WDGS inclusion did not influence DMI. No differences were observed for any carcass characteristics because of urea or WDGS inclusion. Plasma urea nitrogen was greater for cattle as either urea or WDGS inclusion increased. Implications and Applications: These data would suggest that when feeding diets based on dry-rolled corn, adding urea beyond that of the 0.2% treatment is not necessary when at least 10% WDGS is included in the diet

Rising costs and fluctuating availability of supplemental fats has led to increased interest in alternative fat sources, including palm oil products, for use in feedlot diets. The objectives of this experiment were to evaluate the impact of refined, bleached, and deodorized (RBD) palm oil products on beef fat color and quality and shelf-life of ground beef. During the finishing phase, 320 steers (initial BW = 380 ± 14.5 kg) were allocated to 40 pens in a randomized block design and assigned to 1 of 5 dietary treatments, consisting of either no supplemental fat (No Oil), or supplemental corn oil (Corn Oil), whole palm oil (Whole Palm), stearin palm oil (Stearin), or olein palm oil (Olein). Supplemental oils were included at 4% of diet (DM basis) and replaced equal proportions of dry-rolled and high-moisture corn. Forty-eight h post-harvest, briskets were collected from three carcasses per pen, vacuum packaged, aged for 14 d, and frozen until analysis. Data were analyzed using the MIXED procedure of SAS, with pen as the experimental unit, and treatment and initial BW block as fixed effects. Subcutaneous fat from cattle fed Corn Oil was more yellow (b*) compared to cattle fed No Oil, Olein, Stearin, or Whole Palm (P < 0.05). However, there was no effect of treatment on lightness (L*) or redness (a*) of subcutaneous fat (P > 0.69). Ground beef was formulated to a consistent fat content and, as expected, moisture, protein, and fat content was not significantly different among treatments (P > 0.77). However, there was a tendency for ground beef from cattle fed palm oils to have increased collagen content compared to No Oil and Corn Oil treatments (P = 0.10). Beef from cattle fed Corn Oil, Stearin and Whole Palm had increased proportions of linoleic acid (C18:2n-6) compared to No Oil (P < 0.05). The proportions of C14:0, C14:1n-5, C16:0, C16:1n-7, C18:0, C18:1n-9, and C18:3n-3 were not impacted by treatment (P > 0.29). During simulated retail display, ground beef a* decreased from day 0 to day 7 for all treatments and there was an interaction (P < 0.01), where cattle fed Stearin and Whole palm had lower a* values on day 5 compared to No Oil, Corn Oil, and Olein. There was no diet × day interaction for ground beef L* or b* (P > 0.26). There was no diet × day interaction for thiobarbituric acid reactive substances (TBARS; P = 0.59) and there were no treatment effects (P = 0.18). From day 0 to day 7, however, TBARS increased (P < 0.01) for all dietary treatments. This experiment determined that RBD palm oil products have limited impacts on meat quality at this level of inclusion in feedlot diets.