Browsing by Author "Johnson, Bradley J."
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Item A Meta-analysis of the association of Lactobacillus acidophilus NP51 administration with Escherichia coli O157 in feces and on hides of feedlot cattle.(2013-05) Ison, Joshua; Loneragan, Guy H.; Johnson, Bradley J.; Brashears, Mindy M.; Nightingale, Kendra K.Inclusion of the direct-fed microbial (DFM) Lactobacillus acidophilus NP51 (L. acidophilus NP51), in feedlot rations has been associated with decreased burden of Escherichia coli O157:H7 (E. coli O157) in feces and on hides of cattle. The objectives of this meta-analysis were to a) assemble available data from studies that have evaluated an association of L. acidophilus NP51 with E. coli O157; b) reanalyze the data using harmonized statistical models; and c) perform a meta-analysis to produce a summary effect measure and evaluate between study variance. Pen-level fecal and hide prevalence data were gathered from 15 trials that administered L. acidophilus NP51 at 109 CFU/animal/day, 107 CFU/ animal/day, or both. Fecal and hide data were available for 15 and 8 studies, respectively. Data were analyzed to produce study-level relative risk estimates (and their 95% confidence intervals) using generalized linear mixed models. The inverse of study-level variance was used to weight each observation and study-to-study variance was assessed. Outcomes of interest include post-exposure measure of effect, terminal measure of effect, and a dose response. Summary measures of effect from the meta-analysis revealed that E. coli O157 was 42 and 33% less likely to be recovered from feces and hides, respectively, of harvest-ready cattle receiving L. acidophilus NP51 at 109 CFU/animal/day compared to control animals. Fecal E. coli O157 prevalence averaged over time was reduced by 42 and 45% among cohorts receiving high and low doses, respectively. Furthermore, supplementation of L. acidophilus NP51 was associated with a 1.1 log10 CFU/g and 0.26 log10 CFU/g reduction of E. coli O157 concentration in positive fecal samples from cattle receiving high and low doses, respectively.Item A multiple case study analysis of student-athlete academic and social successes in rural-serving Texas community colleges(2015-05) Stewart, Josh S.; Jones, Stephanie J.; Jackson Smith, Dimitra L.; Johnson, Bradley J.; Adams, Gretchen A.There is an increasing gender gap in the success levels of students in higher education. This gap can be seen in both academic and social settings at both the two and four-year level. Institutions of higher education are exploring ways to help increase student success, which commonly are defined by GPA’s, graduation rates and transfer rates. In the social realm, this success is being measured in terms of student engagement role conflict and perceptions of diversity within their immediate environments. The purpose of this study was to explore gender differences in perceptions of the collegiate environment of student-athletes at rural-serving Texas community colleges. Specific attention was given to their perceptions on student success in athletic and social realms. It was necessary to explore the views of the participants and to specifically investigate how each of them defined success in their academic and social environments as community college student-athletes and coaches. Using a qualitative research approach, a multiple case study design allowed the participants to share their thoughts within their natural environment and provide personal insight into their experiences as community college student-athletes and coaches. Kegan’s Orders of Consciousness (1994) provided the theoretical framework for the study. Participants for the study included six student-athletes from rural-serving community colleges, three males and three females, as well as two coaching participants from the same institutions as the student-athletes. The coaching participants consisted of one from a male sport and one from a female sport. Data was collected from the participants using semi-structured interviews, observations, field notes and documents. The analysis process included open and axial coding of the data in order to produce relevant themes of their experiences. Trustworthiness was also addressed in the study by using methods that included triangulation of data, member checking and peer review. The findings of this study presented both similarities and differences in the experiences, perceptions, and approaches of female and male community college student-athletes. Female student-athletes from the study were found to place more importance on the social aspects of their college environment such as new relationships with faculty and friends, non-athletic extra-curricular activities, and time management skills. Additionally, female student-athletes demonstrated a concerted effort to create and maintain a positive outlook for both their academic and athletic environments more so than did male student-athletes. Differences also existed between the two genders’ approaches in academic and social environments. Specifically, female student-athletes placed more emphasis on their academic preparation and academic structure as well as viewing social success as an individual concept rather than a group concept, than did male student-athletes. Similarities existed in the way female and male student athletes perceived success in their academic environment specifically expressing it as an individual living up to their personal capabilities. The results of this study have presented several implications and recommendations for higher education practice. Community colleges have long maintained a goal of providing a holistic learning environment for all students. In this study, both female and male student-athletes demonstrated an adequate understanding of what it means to be academically successful. However, improvements that should be looked at are to continue and improve the increased efforts to provide adequate personal counseling programs through the department of student services. These programs should cover various topics but specifically address the needs to properly navigate time management issues as they relate to the proper balance between personal, social, academic and athletic challenges. The findings have also lead to the need for future research in the areas of student-athlete approaches to the college experience, specifically with large-scale studies in multiple Texas community colleges. These studies should include an examination of student service support programs in the areas of time management, academic planning, social behavior and professional considerations.Item Additive effects of a steroidal implant and zilpaterol hydrochloride on feedlot performance, carcass characteristics, and skeletal muscle messenger ribonucleic acid abundance in finishing steers(2010) Baxa, T.J.; Hutcheson, J.P.; Miller, M.F.; Brooks, J.C.; Nichols, W.T.; Streeter, M.N.; Yates, D.A.; Johnson, Bradley J.This experiment investigated the effects of zilpaterol hydrochloride (ZH) and the steroidal implant Revalor-S (RS; 120 mg of trenbolone acetate and 24 mg of estradiol-17β) on finishing steer performance and the mRNA concentration of β-adrenergic receptors (β-AR) types I and II, and types I, IIA, and IIX myosin heavy chain (MHC) isoforms. A total of 2,279 feedlot steers weighing 426 ± 6.4 kg were administered no implant or RS on d 0, and fed 0 or 8.3 mg of ZH/kg of diet DM during the last 30 d with a 3-d withdrawal. Treatments were randomly assigned to 24 pens (n = 6 pens/treatment). At slaughter, semimembranosus muscle tissue was excised for RNA isolation from 4 carcasses per pen. No interactions were detected for any of the variables measured in the experiment. Administration of ZH during the last 30 d of the feeding period increased (P < 0.01) ADG, G:F, HCW, and LM area; decreased (P < 0.01) 12th-rib fat depth and marbling; and improved (P < 0.01) yield grade. Treatment had no effect on β1-AR mRNA levels, but there was an increase (P = 0.01) in β2-AR mRNA levels due to ZH inclusion. Myosin heavy chain-I (MHC-I) mRNA levels were unaffected by treatment. For MHC-IIA mRNA concentrations, administration of RS tended (P = 0.08) to increase mRNA levels, whereas ZH feeding the last 30 d tended (P = 0.08) to decrease mRNA levels for this isoform of myosin. Feeding ZH the last 30 d before slaughter increased (P < 0.01) mRNA concentrations of MHC-IIX in semimembranosus muscle of steers. These data indicate the combined use of ZH and RS additively contributes to BW and carcass gain in finishing feedlot steers and decreases marbling scores and USDA quality grades. The LM area increased and fat thickness decreased. In addition, ZH feeding changes the mRNA levels of MHC isoforms to a faster, more glycolytic fiber type in bovine skeletal muscle. These changes in mRNA concentrations of MHC isoforms, due to ZH feeding, could be affecting skeletal muscle hypertrophy.Item AMPKα, C/EBPβ, CPT1β, GPR43, PPARγ, and SCD Gene Expression in Single- and Co-cultured Bovine Satellite Cells and Intramuscular Preadipocytes Treated with Palmitic, Stearic, Oleic, and Linoleic Acid(2015) Choi, S.H.; Park, S.K.; Johnson, Bradley J.; Chung, K.Y.; Choi, C.W.; Kim, K.H.; Kim, W.Y.; Smith, B.We previously demonstrated that bovine subcutaneous preadipocytes promote adipogenic gene expression in muscle satellite cells in a co-culture system. Herein we hypothesize that saturated fatty acids would promote adipogenic/lipogenic gene expression, whereas mono- and polyunsaturated fatty acids would have the opposite effect. Bovine semimembranosus satellite cells (BSC) and intramuscular preadipocytes (IPA) were isolated from crossbred steers and cultured with 10% fetal bovine serum (FBS)/Dulbecco’s Modified Eagle Medium (DMEM) and 1% antibiotics during the 3-d proliferation period. After proliferation, cells were treated for 3 d with 3% horse serum/DMEM (BSC) or 5% FBS/DMEM (IPA) with antibiotics. Media also contained 10 μg/mL insulin and 10 μg/mL pioglitazone. Subsequently, differentiating BSC and IPA were cultured in their respective media with 40 μM palmitic, stearic, oleic, or linoleic acid for 4 d. Finally, BSC and IPA were single- or co-cultured for an additional 2 h. All fatty acid treatments increased (p = 0.001) carnitine palmitoyltransferase-1 beta (CPT1β) gene expression, but the increase in CPT1β gene expression was especially pronounced in IPA incubated with palmitic and stearic acid (6- to 17- fold increases). Oleic and linoleic acid decreased (p = 0.001) stearoyl-CoA desaturase (SCD) gene expression over 80% in both BSC and IPA. Conversely, palmitic and stearic acid increased SCD gene expression three fold in co-cultured in IPA, and stearic acid increased AMPKα gene expression in single- and co-cultured BSC and IPA. Consistent with our hypothesis, saturated fatty acids, especially stearic acid, promoted adipogenic and lipogenic gene expression, whereas unsaturated fatty acids decreased expression of those genes associated with fatty acid metabolism.Item Antimicrobial supplementation alters digestibility and ruminal fermentation in a continuous culture model(2021) Thompson, Alex J.; Smith, Zachary K.; Sarturi, Jhones O.; Johnson, Bradley J.A dual-flow continuous culture system was used to evaluate the effects of laidlomycin propionate and bacitracin zinc on fermentation, nutrient digestibility, and microbial efficiency. Factors were laidlomycin propionate (LP; 2 mg/L of culture volume) and bacitracin zinc (BAC; 1.4 mg/L), and treatments were as follows: (1) no BAC or LP (CON), (2) LP without BAC (LP), (3) BAC without LP (BAC), and (4) LP and BAC (LP/BAC). A fifth treatment was supplemented with monensin sodium (MON; 6 mg/L) to act as a positive control. Both LP and LP/BAC had significantly greater pH than MON (P < 0.05). Antibiotic treatment did not affect NH 3-N concentration (P = 0.62), but did influence total VFA production (P = 0.02). Monensin fermenters had a greater proportion of total VFA than did LP fermenters (P < 0.05), and improved VFA production by 7.2% compared to CON. Laidlomycin suppressed the production of both acetate (P < 0.01) and butyrate (P = 0.05), and acetate was further reduced when LP was fed in combination with BAC (P = 0.01). Laidlomycin numerically reduced the acetate:propionate ratio (P = 0.12). These results suggest that bacitracin may produce ionophore-like effects on pH and VFA production in vitro.Item Beef Genetics in the Dairy Management System: Effects of Maternal Genetics and Calf Management System(2023-08) Fuerniss, Luke K.; Johnson, Bradley J.; Rathmann, Ryan J.; Woerner, Dale R.; Hales, Kristin E.; Beckett, Jonathon L.Improved reproductive management has allowed dairy cow pregnancies to be optimized for beef production. Although the use of beef genetics improves calf value, variability has been reported in beef × dairy calf phenotype for traits related to muscularity and carcass composition. The objectives of this research were 1) to evaluate the calfhood growth, feedlot performance, carcass characteristics, and strip loin attributes of beef, beef × dairy, and dairy cattle and 2) to test the effect of the dairy management system compared to the beef management system on calves of all-beef genetics. Tested treatment groups included all-beef calves reared on range (A×B), all-beef calves born to Holstein (H ET) and Jersey (J ET) dams, Angus × Holstein crossbreds (A×H), and Angus × Jersey crossbreds (A×J). A total of N = 87 calves were tested for calfhood growth from birth to approximately 196 d of age. Straightbred Holstein steers (H) were added for the finishing trial in which N = 92 cattle were evaluated. For the finishing trial, cattle were grown to BW of 302 ± 29.9 kg for trial initiation and then fed 196 ± 3.4 d. Individual intake was recorded from d 28 to shipment for harvest. During the finishing phase, a subset of N = 43 steers was selected for repeated serum collection and longissimus thoracis muscle biopsy. After harvest, N = 78 strip loins were evaluated. At birth, A×J calves weighed the least (P < 0.01), and at 150 days of age, body weight was greatest among A×B calves (P < 0.05). Morphometric differences were detected between treatments (MANOVA P < 0.01). When BW was approximately 136 kg, A×B calves had greater top width and lesser hip height than A×J or A×H calves (ANOVA P < 0.01; standardized loadings of -0.48, and 0.63, respectively). During the finishing period, skeletal size measured as hip height, hip width, and body length was greatest for H cattle (P < 0.05). Cattle of all-beef genetics—A×B, H ET and J ET—and A×H had similar final shrunk BW and dry matter intake (P > 0.05). Additionally, meal frequency, meal length, eating rate, and time between meals was similar for cattle of all-beef genetics (P > 0.05). A strong relationship was observed between liver size and dry matter intake (r = 0.73, P < 0.01). Meal-to-meal variability of meal size was greatest for H cattle and least for beef-type cattle (P < 0.05). When adjusted for percentage of adjusted final body weight, feed efficiency was poorest for H (P < 0.05). Among Angus-sired treatments, no difference was observed in marbling score (P > 0.05). No difference was observed in ribeye area between all treatments (P = 0.58), and no difference was observed in muscle fiber area from the longissimus thoracis across the finishing period (P = 0.80). However, H cattle had a more oxidative muscle phenotype than beef-type cattle and lesser L*, a*, and b* values (P < 0.05). Compared to Angus-sired cattle, H cattle had the smallest area of longissimus lumborum in the posterior strip loin, greatest length-to-width ratio of longissimus lumborum in the posterior strip loin, and least round circumference relative to round length (P < 0.05). The dairy management system limited growth of beef genetics during calfhood, but feedlot performance, eating behavior traits, and carcass traits were unaffected by calf management system. Angus genetics transmitted greater muscularity and more moderate mature size than Holstein genetics, and maternal Jersey genetics provided less growth potential than maternal Holstein genetics.Item Body weight and implant effects on animal performance, sera metabolites, and blood pressure in feedlot cattle(2017-11-14) Vogel, Tyler; Johnson, Bradley J.; Neary, Joseph M.; Sarturi, Jhones O.The study objective was to evaluate growth performance, sera metabolites, carcass characteristics and pulmonary arterial pressure as effected by body weight and implant status. Crossbred steers (n = 20) were used in a 2 × 2 factorial design: [body weight: light (L), or heavy (H); implant: Non-implanted (NoIMP), or Implanted (IMP)] with steer as the experimental unit. Initial weights for L and H steers were 398 ± 27.6 and 547 ± 25.2 kg, respectively. Implanted steers received a Revalor-200 (200 mg TBA + 20 mg E2, Merck Animal Health, Madison, NJ) on d 0. Cattle within treatments were group housed in common pens (n = 5 steers/pen). Bodyweight, blood samples, and pulmonary arterial pressure were collected on d 0, 14, 35, 70 and 104. Cattle were fed once daily to provide ad libitum access to feed. The finishing diet contained (DM basis) 13.3% CP, 2.13 Mcal/kg NEm, and 1.45 Mcal/kg NEg. Growth performance and carcass traits were analyzed using the MIXED procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC). Sera metabolites were analyzed as repeated measures over time, with day as the repeated measure. For all analyses, an α level < 0.05 determined significance. Heavy cattle consumed 2.2 kg more per head of DM daily than L cattle (10.14 vs 7.90 kg/d) and IMP steers consumed 1.0 kg more DM daily than NoIMP steers (9.52 vs 8.57 kg/d). Cumulative ADG did not differ between the L and H steers (1.41 vs 1.52 ± 0.06 kg; P = 0.20). Implanting increased (P < 0.01) ADG by 39 % (1.22 vs 1.70 ± 0.06 kg). No differences (P > 0.05) in ADG were observed in NoIMP vs IMP cattle beyond d 70 (1.21 vs 1.01 ± 0.16 kg; P = 0.38). Serum urea - N concentrations were lower (P < 0.01) in L cattle subjected to IMP during the study and tended to increase over time for the other treatments. Ribfat, HCW, LM, marbling score, calculated YG, and EBF were greater (P ≤ 0.05) in H vs L. IMP cattle had heavier HCW (P < 0.01) but decreased marbling scores (P = 0.05) compared to the NoIMP group. Mean pulmonary arterial pressure was greater (P < 0.01) for H vs L cattle which may predispose heavier cattle to right - sided heart failure. The steroid implant had no effect on pulmonary arterial pressure (P > 0.49). The study reaffirms the effects of implanting on growth performance and carcass characteristics in cattle. In addition, elevated BW leads to increased pulmonary arterial pressures which increases the risk of right sided heart failure.Item Body Weight and Steroidal Implants Impact Animal Growth Performance, Sera Metabolites, and Pulmonary Arterial Pressure in Feedlot Cattle(2020) Vogel, Tyler A.; Neary, Joseph M.; Smith, Zachary K.; Johnson, Bradley J.The study objective was to evaluate steer growth performance, sera metabolite responses, carcass characteristics, and pulmonary arterial pressure as affected by body weight at time of implantation and steroidal implant administration. Crossbred steers (n = 20) were used in a 2 × 2 factorial arrangement of treatments in a completely randomized design experiment, Factors included: body weight: light (L), or heavy (H) and implant: Non-implanted (NoIMP), or Implanted (IMP) with steer serving as the experimental unit for all analyses. Initial weights for L and H steers were 398 ± 27.6 and 547 ± 25.2 kg, respectively. Implanted steers received a terminal implant (200 mg trenbolone acetate and 20 mg estradiol-17β; Revalor-200; Merck Animal Health, Madison, NJ) on d 0. Cattle within treatments were group housed in common pens (n = 5 steers/pen). Bodyweight, blood samples, and pulmonary arterial pressure were collected on d 0, 14, 35, 70 and 104. Cattle were fed a common diet once daily to provide ad libitum access to feed. The finishing diet contained (DM basis) 13.3% CP, 2.13 Mcal/kg NEm, and 1.45 Mcal/kg NEg. Growth performance (body weight and ADG) and carcass traits were analyzed using the MIXED procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC). Sera metabolites were analyzed as repeated measures over time, with day as the repeated measure. For all analyses, α level < 0.05 determined significance. Heavy steers consumed 2.2 kg more per head of DM daily than L cattle and IMP steers consumed 1.0 kg more DM daily than NoIMP steers. Cumulative ADG did not differ between the L and H steers (1.41 vs. 1.52 ± 0.060 kg; P = 0.20). Implanting increased (P < 0.01) ADG by 39% (1.22 vs. 1.70 ± 0.060 kg). No differences (P > 0.05) in ADG were observed in NoIMP vs. IMP cattle beyond d 70 (1.21 vs. 1.01 ± 0.16 kg; P = 0.38). Sera urea-N concentrations were decreased (P < 0.01) in L cattle subjected to IMP during the study and tended to increase over time for the other treatments. Ribfat, HCW, LM, marbling score, calculated YG, and estimated EBF were greater (P ≤ 0.05) in H compared to L. Steers from IMP had heavier HCW (P < 0.01) but decreased marbling scores (P = 0.05) compared to NoIMP. Mean pulmonary arterial pressure was greater (P < 0.01) for H compared to L steers which may predispose heavier cattle to right-sided heart failure. The steroid implant had no effect on pulmonary arterial pressure (P > 0.49). The study reaffirms the effects of implanting on animal growth performance and carcass characteristics in cattle. In addition, elevated BW leads to increased pulmonary arterial pressures which may increase the risk of right-sided heart failure.Item Bovine Somatotropin Alters Myosin Heavy Chains and Beta Receptors in Skeletal Muscle of Feedlot Heifers with Little Impact on Live or Carcass Performance(2021) Hergenreder, Jerilyn E.; Baggerman, Jessica O.; Harris, Tyler L.; Thompson, Alex J.; Spivey, Kari S.; Broadway, P. Rand; Vogel, Gary J.; Smith, Zachary K.; Johnson, Bradley J.The objective was to determine whether recombinant bovine somatotropin (rbST) enhanced live performance,skeletal muscle biological activity, and beta-adrenergic receptor expression of feedlot heifers during the finishing phase. Heifers (n = 16; initial body weight = 457 ± 3 kg) were randomly assigned to pens (4 pens/treatment; 2 heads/pen) and treatment: (1) no rbST (Control); (2) 500 mg/hd of sometribove zinc at day 0 and 14 (rbST; Posilac®; Elanco AnimalHealth, Greenfield, IN). Longissimus muscle biopsies for muscle chemistry were collected on day 0, 14, 28, 42, and 56. The rbST heifers had increased expression of AMP-activated protein kinase alpha and beta 3 adrenergic receptor (P < 0.05). Day of the study affected the expression of myosin heavy chain-IIA (MHC-IIA), MHC-IIX, beta 2 adrenergic receptor, peroxisome proliferator-activated receptor gamma, and stearoyl-CoA desaturase (P < 0.05). Day had a significant effect on muscle fiber cross-sectional area and proportion (P < 0.05). As days on feed increased, the area of MHC-I fibers decreased whereas MHC-IIA and IIX area increased (P < 0.05). The rbST heifers had decreased proportions of MHC-I fibers and increased proportions of MHC-IIX fibers (P < 0.05). The greatest density of Paired Box 7-positive cells was on day 0, 28, and 42 (P < 0.05), and the greatest density of Myogenic factor 5-positive cells was on day 42 and 56 (P < 0.05). Also, the greatest density of cells positive for Paired Box 7:Myogenic factor 5 was measured on day 28 (P < 0.05). These data indicate that, as days on feed increase, the effects of skeletal muscle biological activity are not dependent on rbST administration but may be more due to physiological changes occurring as the animal reaches physio-logical maturity.Item Characterizing carcass conformation, meat quality attributes and muscle fiber properties of beef x dairy crossbred cattle(2021-05) Frink, Jenna L.; Woerner, Dale R.; Johnson, Bradley J.; Howard, Scott T.The objective of this study was first, to identify beef quality differences among beef × dairy cattle relative to native beef and dairy cattle, across a range of quality grades, and second, to characterize and understand the true value of this segment in the United States fed-beef supply. Carcasses (n = 560) were selected at 3 separate commercial beef packing facilities based on known cattle type: native beef, beef × dairy or dairy, represented across 4 different USDA Quality Grades: Prime, Upper 2/3 Choice, Choice and Select. Strip loin sections (approximately 5 cm in thickness) were collected from both sides of the carcass and then aged 14 days. At the same time, samples from the longissimus dorsi (0.75cm × 0.75cm × 1.5cm) were frozen for future immunohistochemical analysis (n = 113). After aging, from each pair of strip loins 4 – 2.54 cm steaks were fabricated and stored at -20°C. At fabrication, steaks were assigned to either shear force, trained sensory, consumer sensory or color panel (only USDA Choice carcasses). Shear force steaks were also utilized for dimensionality images and additional pieces from each strip section were allocated to Rapid Evaporative Ionization Mass Spectrometry (REIMS) and pH analyses. Data were analyzed in R (version 4.0, R Core Team, Vienna, Austria) as a completely randomized experiment with a 3×4 factorial arrangement of treatments. Cattle type, USDA Quality Grade, and their interaction (when appropriate) were included as fixed effects. All carcass traits were impacted by cattle type (P < 0.01). Cattle type affected myosin heavy chain isoform IIA proportion (P ≤ 0.01) and beef × dairy cattle had the largest mean cross-sectional area (P ≤ 0.05). Cattle type impacted pH, all trained color panel, L* and a* values and shear force measurements (P < 0.01). Trained sensory analysis indicated tenderness, juiciness and flavor attributes of sour, metallic, fat-like, buttery, liver and oxidized were affected by cattle type (P < 0.01). Consumer sensory analysis also showed tenderness was affected by cattle type (P < 0.01). These results indicate beef × dairy cattle improved aspects of carcass composition when compared to either other cattle type, color stability was preferred to dairy cattle along with recognized improvements in tenderness and flavor performance when compared to native beef. Secondly, the same aforementioned sampling procedures (n = 530) and analyses were utilized to determine the effect of Angus or Continental influenced sires on meat quality characteristics of beef × dairy cattle and compared to native beef and dairy-type cattle (analyzed as a 4 × 4 factorial). Continental influenced sires improved REA relative to dairy type cattle along with trimness and overall yield grade compared to native beef (P < 0.05). Additionally, Angus sires decreased fatness compared to native beef (P < 0.05). Continental influenced beef × dairy cattle produced the least myosin heavy chain IIX fibers and the largest cross-sectional area of myosin heavy chain I, IIA and total fiber area (P < 0.05). Initial color and color stability of strip loin steaks from Angus sired beef × dairy cattle was more ideal relative to Continental influenced sires (P < 0.05). Angus sires also improved tenderness compared to Continental influenced sires as quantified by trained sensory analysis and shear force measurements (P < 0.05). Finally, trained sensory flavor attributes indicated dairy influenced cattle were more ideal than native beef (P < 0.05). To conclude, both Continental-influenced and Angus sired bulls improved characteristics of carcass composition relative to either of their parental breed types and initial color and color stability of ABD was preferred to dairy-type and CIBD cattle. Additionally, both sire types improved tenderness and showed more ideal flavor profiles comparatively to native beef.Item Chromium acetate stimulates adipogenesis through regulation of gene expression and phosphorylation of adenosine monophosphate-activated protein kinase in bovine intramuscular or subcutaneous adipocytes(2020) Kim, Jongkyoo; Chung, Kiyong; Johnson, Bradley J.Objective We hypothesized that Cr source can alter adipogenic-related transcriptional regulations and cell signaling. Therefore, the objective of the study was to evaluate the biological effects of chromium acetate (CrAc) on bovine intramuscular (IM) and subcutaneous (SC) adipose cells. Methods Bovine preadipocytes isolated from two different adipose tissue depots; IM and SC were used to evaluate the effect of CrAc treatment during differentiation on adipogenic gene expression. Adipocytes were incubated with various doses of CrAc: 0 (differentiation media only, control), 0.1, 1, and 10 μM. Cells were harvested and then analyzed by real-time quantitative polymerase chain reaction in order to measure the quantity of adenosine monophosphate-activated protein kinase-α (AMPK-α), CCAAT enhancer binding protein-β (C/EBPβ), G protein-coupled receptor 41 (GPR41), GPR43, peroxisome proliferator-activated receptor-γ (PPARγ), and stearoyl CoA desaturase (SCD) mRNA relative to ribosomal protein subunit 9 (RPS9). The ratio of phosphorylated-AMPK (pAMPK) to AMPK was determined using a western blot technique in order to determine changing concentration. Results The high dose (10 μM) of CrAc increased C/EBPβ, in both IM (p = 0.02) and SC (p = 0.02). Expression of PPARγ was upregulated by 10 μM of CrAc in IM but not in SC. Expression of SCD was also increased in both IM and SC with 10 μM of CrAc treatment. Addition of CrAc did not alter gene expression of glucose transporter 4, GPR41, or GPR43 in both IM and SC adipocytes. Addition of CrAc, resulted in a decreased pAMPKα to AMPKα ration (p<0.01) in IM. Conclusion These data may indicate that Cr source may influence lipid filling in IM adipocytes via inhibitory action of AMPK phosphorylation and upregulating expression of adipogenic genes.Item Chromium propionate enhances adipogenic differentiation of bovine intramuscular adipocytes(2015) Tokach, Rebecca J.; Ribeiro, Flavio R.B.; Chung, Ki Yong; Rounds, Whitney; Johnson, Bradley J.In vitro experiments were performed to determine the effects of increasing concentrations of chromium propionate (CrPro) on mRNA and protein abundance of different enzymes and receptors. Intramuscular (IM) and subcutaneous (SC) preadipocytes and bovine satellite cells were isolated from the longissimus muscle to determine the effect of treatment on glucose transporter type 4 (GLUT4) and peroxisome proliferator-activated receptor γ mRNA and GLUT4 protein abundance. Preadipocyte cultures were treated with differentiation media plus either sodium propionate or different concentrations of CrPro for 96, 120, and 144 h before harvest. This study indicated that adipogenesis of the bovine IM adipocytes were more sensitive to the treatment of CrPro as compared to SC adipocytes. Enhancement of adenosine monophosphate-activated protein kinase and GLUT4 mRNA by CrPro treatment may enhance glucose uptake in IM adipocytes. CrPro decreased GLUT4 protein levels in muscle cell cultures suggesting that those cells have increased efficiency of glucose uptake due to exposure to increased levels of CrPro. In contrast, each of the two adipogenic lines had opposing responses to the CrPro. It appeared that CrPro had the most stimulative effect of GLUT4 response in the IM adipocytes as compared to SC adipocytes. These findings indicated opportunities to potentially augment marbling in beef cattle fed CrPro during the finishing phase.Item Chromium propionate supplementation alters animal growth performance, carcass characteristics, and skeletal muscle properties in feedlot steers(2020) Baggerman, Jessica O.; Smith, Zachary K.; Thompson, Alex J.; Kim, Jongkyoo; Hergenreder, Jerilyn E.; Rounds, Whitney; Johnson, Bradley J.The objective of this study was to evaluate the effects of increasing concentrations of Cr propionate (CrP) on feedlot performance, blood parameters, carcass characteristics, and skeletal muscle fiber properties in feedlot steers. Crossbred steers (n = 32; 367 ± 2.5 kg; 16 pens; 2 hd/pen) were blocked by body weight (BW), and treatment was randomly assigned to pen: (1) 0 mg added Cr/kg diet dry matter (DM) (control), (2) 0.15 mg added Cr/kg diet DM (CrP; KemTRACE Chromium 0.04%, Kemin Industries, Des Moines, IA), (3) 0.30 mg added Cr/kg diet DM, and (4) 0.45 mg added Cr/kg diet DM. Steers were fed ad libitum, and the treatment was top-dressed at the time of feeding. Body weights, blood samples, and longissimus biopsies were collected before feeding on days 0, 28, 56, 91, 119, and 147. Blood sera were harvested for analysis of glucose, insulin, sera urea nitrogen, and non-esterified fatty acid concentrations. Longissimus biopsies were collected for gene expression, protein expression, and immunohistochemical (IHC) analysis. Pen was the experimental unit for live and carcass data, and steer was the experimental unit with day as a repeated measure for sera and IHC analyses. For the entire duration of the trial, a linear increase in average daily gain (ADG) (P = 0.01) and improvement in G:F was observed (P = 0.01) with no change in DMI (P = 0.11) with increasing CrP. A linear increase in hot carcass weight (HCW) (P ≤ 0.01) with no other changes in carcass composition were noted (P ≥ 0.38) as the level of dietary CrP increased. There was no effect of treatment on any sera parameters measured (P ≥ 0.10). No difference was detected for gene or protein expression of glucose transporter type 4 (GLUT4) due to CrP supplementation (P ≥ 0.10). For skeletal muscle fiber distribution and cross-sectional area, there was no effect of treatment (P ≥ 0.10). Density of total GLUT4 did not change due to CrP (P ≥ 0.10). Internalization of GLUT4 was increased in the 0.30 and 0.45 mg/kg treatments (P < 0.01). For total nuclei density and myonuclei density, there were treatment × day interaction tendencies (P ≤ 0.08). Supplementation of CrP did not alter density of satellite cells (P ≥ 0.10). The number of transporters located in the sarcolemma of skeletal muscle fibers did decrease, implying fewer proteins were needed to transport extracellular glucose into the muscle fiber. Therefore, CrP may augment cellular function and growth via increased efficiency of GLUT4 function. These results indicated CrP increases BW, ADG, and HCW, without changes in circulating sera parameters or total GLUT4 expression.Item Comparison of beta-ligands used in cattle production: structures, safety, and biological effects(2021) Dilger, Anna C.; Johnson, Bradley J.; Brent, Paul; Ellis, Richard L.Technologies that increase the efficiency and sustainability of food animal production to provide meat for a growing population are necessary and must be used in a manner consistent with good veterinary practices, approved labeled use, and environmental stewardship. Compounds that bind to beta-adrenergic receptors (β-AR), termed beta-adrenergic receptor ligands (β-ligands), are one such technology and have been in use globally for many years. Though all β-ligands share some similarities in structure and function, the significance of their structural and pharmacological differences is sometimes overlooked. Structural variations in these molecules can affect absorption, distribution, metabolism, and excretion as well as cause substantial differences in biological and metabolic effects. Several β-ligands are available for use specifically in cattle production. Ractopamine and zilpaterol are beta-adrenergic agonists approved to increase weight gain, feed efficiency, and carcass leanness in cattle. They both bind to and activate β1- and β2-AR. Lubabegron is a newly developed selective beta-adrenergic modulator with unique structural and functional features. Lubabegron displays antagonistic behavior at the β1- and β2-AR but agonistic behavior at the β3-AR. Lubabegron is approved for use in cattle to reduce ammonia emissions per unit of live or carcass weight. Additionally, lubabegron can withstand prolonged use as the β3-AR lacks structural features needed for desensitization. Due to these unique features of lubabegron, this new β-ligand provides an additional option in cattle production. The individual properties of each β-ligand should be considered when making risk management decisions, as unique properties result in varying human food safety profiles that can determine appropriate safe β-ligand use.Item Dehydrated citrus pulp alters feedlot performance of crossbred heifers during the receiving period and modulates physiological and acute phase responses and metabolite concentrations(2012-12) Cribbs, Joshua; Rathmann, Ryan J.; Johnson, Bradley J.; Carroll, Jeffery A.A study was designed to determine the effects of feeding dehydrated citrus pulp (DCP) on feedlot performance of newly-received English × Continental heifers. Heifers (n=180) were sourced in two loads (188.7 ±18.0 kg and 225.2 ± 22.2 kg, respectively) from commercial auction barns and placed on trial at the Texas Tech University Beef Center in New Deal, Texas. A completely randomized block design was utilized with BW nested within arrival load and blocked by BW. Three dietary treatments were fed (36 pens; 5 heifers/pen; 12 blocks; 3 pens/block; 12 pens/treatment). Treatment diets were formulated to contain: 1) 0%; 2) 10%; or 3) 20% DCP on a DM basis. Diets containing DCP were formulated to be exchanged with steam flaked corn on a 1:1 basis. Cattle were fed a 63, 73, and 83% concentrate diet from d 0 to 28, d 28 to 42, and d 42 to 56, respectively. Over the entire 56-d trial period, as the amount of dietary DCP increased DMI decreased (P = 0.02; 6.70, 6.13, and 5.96 kg, for 0, 10, and 20% DCP, respectively), ADG decreased (P < 0.0001; 1.88, 1.27, and 1.00, respectively), and G: F decreased (P = 0.02; 0.225, 0.210, 0.191, respectively). From d 0 to d 28 there was no difference in the observed, minus the expected NEg of the diet (P = 0.73), from d 28 to d 42 there was a linear increase in NEg with an increase in the percentage of DCP (P=0.003), and from d 42 to d 56 there was a linear increase in NEg favoring CON cattle over DCP cattle (P = 0.006). At the conclusion of the trial a subset of heifers (n = 24; 218.3 ± 2.4 kg) were utilized to evaluate the physiological and acute phase responses (APR) to an endotoxin (lipopolysaccharide; LPS) challenge. On d 63, heifers were fitted with jugular catheters and moved into individual stalls. On d 64, heifers were challenged i.v. with LPS (0.5 µg/kg BW), and blood samples were collected every 0.5 h from -2 to 8 and again at 24 h relative to LPS challenge (0h). Sickness behavior scores (SBS) were assigned following collection of each blood sample. Serum was analyzed for cortisol, interleukin-6 (IL-6), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) concentrations as well as serum glucose, blood urea nitrogen (BUN), and non-esterified fatty acid (NEFA) concentrations. Post-LPS SBS increased (P < 0.01) and were greater in 10% DCP than 20% DCP and CON. Heifer BW was measured at cannulation, and 24 and 72-h ) post-LPS. BUN levels showed a treatment effect pre-LPS favoring CON cattle (P < 0.01). Post-LPS glucose, NEFA, and BUN concentrations were greater in CON cattle (P < 0.01) cortisol concentrations were greatest in 10% DCP heifers than CON and 20% DCP treatments ( P < 0.01). IFN-γ, TNF-α, and IL-6 increased post-LPS (P < 0.01) and were greater in 20% DCP over 10% DCP and CON treatments ( P < 0.01). These data indicate that dietary DCP can modulate both the physiological and APR of newly-received heifers to an endotoxin challenge, and it effects feedlot performance variables.Item Determination of Package and Muscle-Type Influence on Proteolysis, Beef-Flavor-Contributing Free Amino Acids, Final Beef Flavor, and Tenderness(2020) Vierck, Kelly R.; Legako, Jerrad F.; Kim, Jongkyoo; Johnson, Bradley J.; Brooks, J.C.The objectives of this study were to determine the influence of package and muscle type on postmortem proteolysis and subsequent release of flavor-contributing free amino acids during storage. Beef strip loins and top sirloin butts (n = 20/subprimal) from USDA Low Choice carcasses were fabricated into 2.54-cm steaks (M. longissimus lumborum and M. gluteus medius) at 7 d postmortem. Steaks were randomly assigned to packaging treatments (carbon monoxide mother-bag [CO], high-oxygen modified atmosphere packaging [HIOX], polyvinyl overwrap [OW], or rollstock [ROLL]) and aged for an additional 14 d in dark storage. Steaks intended for OW were initially vacuum packaged during dark storage,then overwrapped just prior to display. Steaks were placed in coffin-style retail cases for 48 h under fluorescent lighting to simulate retail display. HIOX steaks exhibited the highest Warner-Bratzler shear force values (P < 0.05); the lowest desmin degradation rate (P < 0.05); the highest ratings for fishy, bitter, sour, and oxidized flavors; and the lowest overall tenderness scores (P < 0.05) and, in general, produced the lowest amount of free amino acids (P < 0.05) compared with all other treatments. Contrastingly, ROLL packaging produced the highest ratings for beef flavor identity, brown/roasted, bloody/serumy, and umami flavors (P < 0.05). Additionally, ROLL packaging exhibited (P < 0.05) greater desmin degradation in comparison with HIOX steaks. These data indicate that the optimum package for storage and aging is an anaerobic environment to maintain optimum flavor, tenderness, and postmortem proteolysis.Item Dose and release pattern of anabolic implants affects growth of finishing beef steers across days on feed(2011) Parr, S.L.; Chung, K.Y.; Hutcheson, J.P.; Nichols, W.T.; Yates, D.A.; Streeter, M.N.; Swingle, R.S.; Galyean, M.L.; Johnson, Bradley J.Four experiments evaluated the effect of implant dose and release pattern on performance and carcass traits of crossbred beef steers. In Exp. 1, steers (4 to 7 pens/treatment; initial BW = 315 kg) were fed an average of 174 d. Treatments were 1) no implant (NI); 2) Revalor-S [120 mg of trenbolone acetate (TBA) and 24 mg of estradiol 17β (E2); REV-S]; 3) Revalor-IS followed by REV-S (cumulatively 200 mg of TBA and 40 mg of E2; reimplanted at 68 to 74 d; REV-IS/S); and 4) Revalor-XS (200 mg of TBA and 40 mg of E2; REV-X). Carcass-adjusted final BW was greater (P < 0.05) for REV-X and REV-IS/S than for REV-S (610, 609, and 598 kg, respectively). Daily DMI did not differ (P > 0.10) among the 3 implants, but carcass-adjusted G:F was greater (P < 0.05) for REV-X and REV-IS/S than for REV-S (0.197 and 0.195 vs. 0.188). Both HCW and LM area were greater (P < 0.05) for REV-X and REV-IS/S than for REV-S. Marbling scores were greatest (P < 0.05) for REV-S and least (P < 0.05) for REV-IS/S; REV-X was intermediate to NI and REV-IS/S. In Exp. 2, steers (10 pens/treatment; initial BW = 391 kg) were fed 131 d, with treatments of REV-S, REV-IS/S (reimplanted at 44 to 47 d), and REV-X. Carcass-adjusted final BW (598 kg), ADG (1.6 kg), DMI (9.4 kg), G:F (0.17), and HCW did not differ (P > 0.10) among treatments. The percentage of Choice was less (P < 0.05) and percentage of Select greater (P < 0.05) for REV-IS/S than for REV-S and REV-X. In Exp. 3, steers (10 pens/treatment; initial BW = 277 kg) were fed 197 d and received either REV-IS/S (reimplanted at 90 to 103 d) or REV-X. Carcass-adjusted final BW (625 vs. 633 kg) and ADG (1.81 vs. 1.76 kg) were greater (P < 0.05) for REV-X-implanted steers. Daily DMI did not differ, but G:F tended (P < 0.10) to be increased and HCW was greater (P < 0.05) for REV-X than for REV-IS/S. In Exp. 4, steers (8 pens/treatment; initial BW = 238 kg) were fed 243 d and received either REV-IS/S (reimplanted at 68 to 71 d) or REV-X. Carcass-adjusted final BW (612 kg), ADG (1.54 kg), DMI (7.55), and G:F (0.21) did not differ (P > 0.10) for REV-IS/S and REV-X-implanted steers. Carcass traits did not differ among implants, but the percentage of Choice carcasses was greater (P < 0.05) and percentage of Select was less (P < 0.05) for REV-X than for REV-IS/S. These data indicate that when TBA/E2 dose is equal, the altered release rate of REV-X can improve performance and quality grade, but these effects depend on duration of the feeding period and timing of initial and terminal implants.Item Duration of exposure to a high-concentrate diet prior to pasture-finishing affects palatability of beef strip loin steaks(2018-05) Milopoulos, Jillian Taylor; Miller, Markus F.; Brooks, J. Chance; Legako, Jerrad F.; Johnson, Bradley J.Most cattle in the United States are finished on high-energy, grain-based diets. However, perceived health benefits have led to an increase in consumer interest in pasture-fed beef. Production of pasture-fed beef depends on seasonal patterns of pasture quality, and pasture-fed beef has been reported to have less favorable palatability traits than grain-fed beef. The current study was designed to determine if early feeding of a grain-based diet when pasture quality is low could produce palatable pasture-finished beef. Angus-cross steers (n = 48 [12 head / treatment]) were provided a high-concentrate diet for 0 d (0D), 40 d (40D), 80 d (80D), or 120 d (120D) prior to pasture-finishing on high-quality forages to a target final BW (487 kg). Strip loins were collected at harvest, and 8 were selected from each treatment based on USDA marbling scores targeting USDA Select quality grade (average marbling score: 370 ± 33.1). Eight additional process-verified grass-fed strip loins were selected from a commercial harvest facility in New Zealand to be included as a baseline (NZ). Strip steaks were used for proximate analysis, objective tenderness measurement, consumer assessment of palatability, determination of fatty acid composition, and quantification of volatile compound. Proximate composition and Warner-Bratzler shear force did not differ (P > 0.05) among treatments. Consumers (n = 220) assigned the greatest scores for tenderness to NZ (P < 0.05), and NZ was most often rated as acceptable for tenderness (P < 0.05). Steaks from NZ and 120D received greater sensory scores for juiciness than 0D and 80D (P < 0.05); 40D was intermediate (P > 0.05). Samples from 120D were more often rated as acceptable than 0D, 40D, and 80D (P < 0.05). Flavor scores were greater for NZ than all other treatments (P < 0.05) except 120D (P > 0.05). Percentage of samples rated as acceptable for flavor did not differ among treatments (P = 0.27). Samples from 120D and NZ received greatest scores for overall liking (P < 0.05), and NZ was more often rated as acceptable for overall liking than all treatments (P < 0.05) except 120D (P > 0.05). Flavor was highly correlated with overall liking (P < 0.01; r = 0.89). Saturated fatty acids were decreased (P < 0.05) and monounsaturated fatty acids increased (P < 0.05) in NZ compared to all other treatments. Odd-chain fatty acids were greater with grain exposure (40D, 80D, 120D; P < 0.05) than in pasture-finished treatments (NZ, 0D). Trans-vaccenic acid was greater (P < 0.05) in treatments exposed to grain than NZ, and conjugated linoleic acid was greater (P < 0.05) in all other treatments than NZ. The ratio of n-6 to n-3 polyunsaturated fatty acids was greater (P < 0.05) in 80D and 120D than all other treatments. Samples from NZ produced the greatest amounts of non-enzymatic browning-derived ketones (2,3-butanedione and 3-hydroxy-2-butanone; P < 0.05). Differences among treatments in lipid-derived volatile compounds were primarily of alcohols and aldehydes. In particular, 1-penten-3-ol was greater in NZ than all other treatments (P > 0.05). Hexanal was greater in NZ than all other treatments (P < 0.05) except 80D (P > 0.05), and octanal was greater in NZ than 80D and 120D (P < 0.05). Additionally, 2-pentylfuran was greater in NZ than all other treatments (P < 0.05). Results indicate that early exposure to grain-based diets for 120 d prior to pasture-finishing may produce beef that is comparable to grass-fed beef from New Zealand in palatability, but beef produced in pasture-finishing systems in the United States, with or without grain exposure, differs chemically from beef produced under New Zealand grass-fed systems.Item Effect of Direct-Fed Microbial Supplementation on Pathogenic Escherichia coli Fecal Shedding, Live Performance, and Carcass Characteristics in Feedlot Steers(2020) Thompson, Alex; Calle, M. Alexandra; Ribeiro, Flavio R.B.; Pond, Ansen R.; Kreikemeier, Wanda M.; McDonald, Allen; Johnson, Edward G.; Edmonds, Matthew D.; Loneragan, Guy H.; Brashears, Mindy M.; Johnson, Bradley J.Three experiments were conducted to evaluate direct-fed microbial (DFM) supplementation on live performance, carcass characteristics, and fecal shedding of E. coli in feedlot steers. In Exp. 1, 400 steers (BW = 348 kg) were assigned to treatments: CON = lactose carrier only, BOV = P. freudenreichii (NP24) + L. acidophilus (NP51), BOVD = P. freudenreichii (NP24) + L. acidophilus (NP51), and COMB = BOV fed for the first 101 d on feed, followed by BOVD for the final 28 d prior to harvest. In Exp. 2 (n = 1800; BW = 354 kg) and Exp. 3 (n = 112; BW = 397 kg), steers were utilized in a randomized complete block design and assigned to DFM treatments using low dose and high dose, respectively. Fecal samples were collected prior to harvest and analyzed for E. coli serogroups. In Exp. 1, DFM reduced (P < 0.01) the concentration of E. coli O157. Prevalence of O157 was reduced by BOVD supplementation in Exp. 2 and 3 (P < 0.01 and P = 0.08, respectively), and concentration of E. coli O157 in positive samples was reduced in both experiments where enumeration was performed (P ≤ 0.02). Weighted mean differences across the three experiments were equal to a 33% reduction in the prevalence of E. coli O157:H7 in BOVD treated cattle. A significant reduction in prevalence of O26, O45, O103, and O121 was observed in Exp. 2 (P ≤ 0.03). These results indicate that high levels of L. acidophilus (NP51) may represent an effective pre-harvest food safety intervention to reduce fecal shedding of several E. coli serogroups.Item Effect of feeding zilpaterol hydrochloride to beef and calf-fed Holstein cattle on consumer palatability ratings(2009) Mehaffey, J.M.; Brooks, J.C.; Rathmann, R.J.; Alsup, E.M.; Hutcheson, J.P.; Nichols, W.T.; Streeter, M.N.; Yates, D.A.; Johnson, Bradley J.; Miller, M.F.The need to provide consumer data for beef steak tenderness, juiciness, flavor, and overall palatability ratings from zilpaterol hydrochloride (ZH) beef to the processor, retailers, restaurants, and consumers is paramount. Consumer palatability responses were studied for 14- and 21-d aged USDA Choice and USDA Select quality grade beef and USDA Choice calf-fed Holstein New York Strip steaks from cattle that had been fed ZH for 0, 20, and 30 d before slaughter. Strip loins were cut into 2.54-cm-thick New York strip steaks and assigned to a 14- or 21-d aging treatment. The first and fourth steaks were assigned for 14- or 21-d WBSF analysis, and the second, third, fifth, and sixth steaks were reserved for consumer sensory panel evaluation. Warner-Bratzler shear force (WBSF) analysis was conducted at Texas Tech University (TTU, Lubbock), Kansas State University (Manhattan), Oklahoma State University (Stillwater), and West Texas A&M University (Canyon) with values used to sort steaks for consumer evaluation. Slice shear force analysis was performed at TTU on available paired consumer steaks. Consumers (n = 3,007) in 4 metropolitan areas (Baltimore, MD/Washington, DC; Chicago, IL; Los Angeles, CA; and Lubbock, TX) were asked to rate tenderness, juiciness, flavor, and overall acceptability. Consumers were selected to represent a wide range of income, education, and ethnicity at each city. Steaks were cooked to a medium degree of doneness (71°C), cut into 1 cm3 pieces, and served warm to consumers. Consumers tasted samples from each of 3 separate steaks from each ZH treatment (0, 20, and 30 d) and within each USDA quality grade and within the 14- and 21-d aging treatments. Steaks were selected to represent the distribution of tenderness for the first, second, and third SD either side of the mean for each treatment. A second calf-fed Holstein consumer study (n = 240) was conducted with consumers eating USDA Choice 14- and 21-d aged steaks from Holstein cattle fed ZH for 0 or 20 d. Steaks from 0- and 20-d ZH treatments were different for tenderness for the 14-d aged USDA Choice and the calf-fed Holstein study groups. No differences were shown for all other 0- and 20-d ZH treatments for tenderness. The 21-d aged USDA Select steaks were improved with aging, which aided in removing the effects of ZH treatment. The ZH treatment of 30 d before slaughter resulted in increased WBSF values and decreased consumer tenderness, juiciness, and overall palatability ratings for 14-d-aged USDA Choice. No differences were shown for tenderness, juiciness, flavor, and overall palatability consumer ratings for 0- and 20-d steaks from 21-d Choice and 14- and 21-d Select quality and aging periods. Overall, USDA Choice Holstein steaks aged 14 and 21 d had differences in tenderness with ZH.