Browsing by Author "Hergenreder, Jerilyn E."
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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 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 Effects of Bacillus subtilis PB6 and/or chromium propionate supplementation on serum chemistry, complete blood count, and fecal Salmonella spp. count in high-risk cattle during the feedlot receiving and finishing periods(2020) Smock, Taylor M.; Samuelson, Kendall L.; Wells, Jim E.; Hales, Kristin E. (TTU); Hergenreder, Jerilyn E.; Whitney Rounds, P.; Richeson, John T.The study objective was to determine the effects of Bacillus subtilis PB6 and/ or chromium propionate supplementation on serum chemistry, complete blood count, and fecal Salmonella spp. count in high-risk beef cattle during a 56-d feedlot receiving period and the subsequent finishing period. Four truckload blocks of crossbred beef bulls (n = 300) and steers [n = 84; total n = 384; average initial body weight (BW) = 220 ± 16.2 kg] were sourced from regional auction markets and assigned randomly to treatments arranged in a 2 × 2 factorial. Blood samples were collected from two bulls nearest to the median BW on arrival in each pen (n = 96) and fecal samples were collected from cattle in block 3 (n = 96). The generalized complete block design consisted of 12 pen replications per treatment with pen as the experimental unit. Treatments were: 1) negative control (CON); 2) 13 g per animal daily of prepared B. subtilis PB6 product (CST); 3) 450 ppb dry matter (DM) chromium propionate (CHR); and 4) 13 g per animal daily of prepared B. subtilis PB6 product and 450 ppb DM chromium propionate (CST + CHR). Treatments were top dressed in feed bunks daily using 0.45 kg per animal ground corn carrier immediately following feed delivery. Data were analyzed using mixed models with repeated measures. Day affected all serum chemistry variables (P ≤ 0.03) except total CO2 (P = 0.34) and all complete blood count variables during receiving (P ≤ 0.02) except percentage basophils (P ≥ 0.12). During the overall receiving period, serum calcium was decreased (P = 0.02) by CHR. Cattle fed CHR had greater total leukocyte count (P = 0.04) and neutrophil count (P = 0.02) during the overall receiving period. Fecal Salmonella spp. count was markedly reduced in cattle fed CST on day 28 (P = 0.01) and overall (P = 0.07). Overall, these data provide metabolic and hematologic insight into the unique challenges presented by lightweight, high-risk feeder cattle. Notably, CST was found to be effective in mitigating fecal enumeration and presumably replication of Salmonella spp. in the gastrointestinal tract.Item Effects of Encapsulated Methionine on Skeletal Muscle Growth and Development and Subsequent Feedlot Performance and Carcass Characteristics in Beef Steers(2021) Baggerman, Jessica O.; Thompson, Alex J.; Jennings, Michael A.; Hergenreder, Jerilyn E.; Rounds, Whitney; Smith, Zachary K.; Johnson, Bradley J.Two studies were conducted to evaluate the effect of encapsulated methionine on live performance, carcass characteristics, and skeletal muscle development in feedlot steers. In Experiment 1, 128 crossbred steers (body weight [BW] = 341 ± 36.7 kg) were used in a randomized complete block design and supplemented with 0, 4, 8, or 12 g/(head day [d]) of ruminally protected methionine (0MET, 4MET, 8MET, and 12MET, respectively) for 111 d or 139 d. In Exp. 2, 20 steers (BW = 457 ± 58 kg) were stratified by BW and randomly assigned to either the 0MET or 8MET treatment; longissimus muscle (LM) biopsies were collected on d 0, 14, 28, 42, and 56, and analyzed for mRNA and protein expression. Additionally, immunohistochemical analysis was performed to measure fiber type area and distribution as well as the density of muscle nuclei and satellite cells (Myf5, Pax7, and Myf5/Pax7). In Experiment 1, no significant differences were observed for live performance (p ≥ 0.09). There was, however, a linear relationship between LM area and methionine supplementation (p = 0.04), with a 9% increase in the area when steers were supplemented with 12MET compared to 0MET. In Exp. 2, There were no treatment × day interactions (p ≥ 0.10) for expression of mRNA or protein abundance. Although mRNA expression and protein abundance of all genes were influenced by day (p ≤ 0.04), methionine supplementation did not have a significant effect (p ≥ 0.08). There was a significant treatment × day interaction for distribution of MHC-I fibers (p = 0.03), where 8MET supplemented cattle had a greater proportion of MHC-I fibers after 56 d of supplementation than did 0MET steers. Cross-sectional area was increased over time regardless of fiber type (p < 0.01) but was unaffected by treatment (p ≥ 0.36). While nuclei density was not impacted by treatment (p = 0.55), the density of myonuclei increased nearly 55% in 8MET supplemented cattle (p = 0.05). The density of Myf5 positive satellite cells tended to decrease with methionine supplementation (p = 0.10), while the density of Pax7 expressing cells tended to increase (p = 0.09). These results indicate that encapsulated methionine supplementation may influence markers of skeletal muscle growth, and potential improvements in the LM area may exist.Item A Greater dose of Ractopamine Hydrochloride Enhances Feedlot Performance and Impacts Carcass Characteristics of Calf-Fed Holstein Steers(2021) Hergenreder, Jerilyn E.; Beckett, Jonathon L.; Smith, Zachary K.; Johnson, Bradley J.The objective was to evaluate the effects of supplementing ractopamine HCl at the rate of 400 mg steer1 daily in the final 28 d of the feeding period on growth performance and carcass characteristics of Holstein steers. Steers (n = 1,498; initial BW = 547 kg) were randomly assigned to pens (10 pens/treatment) and to a treatment: (1) 0 mg∙steer1∙d1 of RH (CON); (2) Ractopamine HCl fed at 400 mg∙steer1∙d1 of RH (RH) for evaluation over a 28 d period. Steers were fed a finishing diet based on steam-flaked corn and alfalfa hay. Dry matter intake decreased, Average Daily Gain (ADG) was increased and improved feed efficiency (P<0.05) was noted in RH steers. Steers supplemented with RH had heavier final Body Weight (BW) and HCW, greater Dressing Percentage (DP) and larger Longissimus Muscle (LM) area (P<0.05). Ractopamine HCl steers had improved yield grades, as evidenced by a greater percentage of yield grade 1 and a decreased percentage of yield grade 3 (P<0.05) carcasses. Steers supplemented RH had a decreased percentage of cattle grading USDA Choice and a greater percent grading USDA Select (P<0.05). These data indicate that 400 mg∙steer1 daily of ractopamine HCl fed to Holstein steers may improve feedlot phase growth performance, DP, HCW and LM area while having minimal impact on USDA quality grade distribution.Item Growth promotant supplementation alters live performance and carcass characteristics while impacting cellular metabolism, gene expression, and protein synthesis(2014-12) Hergenreder, Jerilyn E.; Johnson, Bradley J.; Brooks, J. Chance; Rathmann, Ryan J.; Trojan, Sara J.; Walker, Dillon K.Growth promotants have been shown to positively impact production parameters such as live performance and efficiency, carcass characteristics, and ultimately profitability. Therefore, the objectives of this study were to elucidate the molecular mechanisms by which these growth promotants affect production. To asses’ performance, feeding efficiency parameters were monitored followed by carcass characteristic evaluation at harvest. Real-time quantitative reverse transcription polymerase chain reaction, immunohistochemistry, and western blots were preformed on all tissue samples. There was no difference in growth performance or carcass characteristics of steers supplemented with a zinc-methionine complex (ZnMet) or heifers administered recombinant bovine somatotropin (rBST; P > 0.05). Bovine satellite cells, steers and heifers administered the beta-adrenergic agonist, zilpaterol HCl (ZH) increased the abundance of myosin heavy chain (MHC)-IIX mRNA (P < 0.05). Treatment with ZH or ZnMet did not affect the protein abundance of beta-adrenergic receptors (β-AR) in tissue or satellite cells. Zinc-methionine supplemented animals had a greater abundance of MHC-II protein (P < 0.05). The administration of rBST and the supplementation of ZH and ZnMet increased MHC-I, IIA, and IIX fiber cross-sectional area (P < 0.05). Zilpaterol HCl and rBST decreased the proportion of MHC-I fibers (P < 0.05) and increased the proportion of MHC-IIX fibers (P < 0.05). The ZnMet treatment increased the proportion of MHC-I fibers (P < 0.05) and decreased the proportion of MHC-IIX fibers (P < 0.05) in comparison to steers just supplemented with ZH. Supplementation of ZH and ZnMet tended to decrease the density of β2-AR (P < 0.10) and increase the density of internalized β2-AR in skeletal muscle (P < 0.10). The rBST had no affect on β-AR or satellite cell density (P > 0.05). The density of Myf5 satellite cells was decreased (P < 0.05) in ZH heifers. Steers supplemented with ZnMet had a greater density of Pax7 satellite cells (P < 0.05). Overall, these data revealed that different growth promotants impact cellular muscle metabolism via multiple cellular mechanisms, and these cellular differences may ultimately impact performance and profitability.