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A total of 42 F1 Red Angus progeny from sires divergent in maintenance energy (MEM) EPD were analyzed to determine whether selecting for sire MEM would alter end-product meat quality. Data from animals were grouped based on the divergence of the MEM EPD of their sire from the Red Angus Association-reported breed average and defined as either high or low, the assumption being that high-MEM cattle are less efficient because their maintenance requirements represent a larger proportion of their dietary intake. Steer progeny (n = 7) from the high group produced bottom round steaks with a greater a* (redness) color value (P = 0.02) after 5 d in a simulated retail display when compared with bottom round steaks from the low group (n = 18). Bottom round steaks from the high group had a greater b* (yellowness) color value at d1 (P = 0.03) and d 5 (P = 0.01) of retail display. Samples from the biceps femoris were taken at 12 mo (from both steers and heifers) and 15 mo (from steers only) of age for fiber type proportion analysis. At 12 mo of age, steers from the low group had more type I fibers (P = 0.02), whereas steers from the high group had more type IIb fibers (P = 0.01). Furthermore, samples from steers in the low group at 15 mo had more type I fibers (P = 0.02), and steers from the high group maintained more type IIb fibers (P = 0.02). No changes in fiber type proportions were observed between the high- and low-MEM EPD heifers (n = 17). Relative mRNA abundance of genes involved in the synthesis, storage, and breakdown of glycogen were analyzed as a variable important for meat quality, but no statistical differences were observed. At 12 mo age, glycogenin (glyc) was negatively correlated with the proportion of type IIa fibers (r = -0.32 and P = 0.12) as well as with the proportion of type IIb fibers (r = -0.42 and P = 0.03) in the biceps femoris of the steers. In samples taken from the biceps femoris at 15 mo age, glyc was negatively correlated with the proportion of type IIa fibers (r = -0.42 and P = 0.03) in the steers. This indicates that relative mRNA expression of glyc may serve as a marker of muscle glycogen storage capacity in steers. Thus, selection for efficient Red Angus beef cattle based on sire MEM EPD does not adversely affect meat quality in F1 progeny, based on the variables assessed in this study. Furthermore, selection for progeny from low-MEM EPD sires may improve fresh meat quality within Red Angus beef cattle. [ABSTRACT FROM AUTHOR]

This study examined the effect of dietary rumen-protected histidine (HIS) supplementation in cattle on growth and carcass traits/product quality. Three levels of daily HIS (Balchem Corp.) were tested (control, low dose [DL], and high dose [DH]) over a 55-d finishing period in 48 crossbred steers implanted with Revalor-XS. Cattle were randomly allocated into 8 pens of 6 steers each and fed twice daily using Calan gates. Morning feed was top-dressed with the HIS as follows: control (no HIS), 50 g/steer per day (DL), or 100 g/steer per day (DH). Individual intakes were recorded, and feed and orts were analyzed every 5 d during the feeding period. Steers were harvested, carcass data was recorded, and carcasses were fabricated at a USDA-inspected facility. One longissimus lumborum (LL) and 1 gluteus medius (GM) was acquired from each animal, aged under vacuum (21 and 14 d respectively), and cut into 2.54-cm steaks. One steak was used for retail display for which subjective (to evaluate visual color components) and objective (L*, a*, and b*) color scores were recorded. Lipid oxidation on d 0 and 9 of retail display were assessed using thiobarbituric acid reactive substances. Another steak was used to evaluate cooking loss and tenderness using Warner-Bratzler shear force. Sensory taste panels were conducted (1 panel for each muscle) to determine consumer perception of the product. Muscles were analyzed using HPLC for HIS metabolite (anserine and carnosine) and HIS content. Histidine supplementation increased ADG during d 1 to 21 (DH, P = 0.07), d 42 to 60 (DL and DH, P = 0.07), and the final 50 d (DH, P = 0.07) of feeding. Supplementation with HIS also increased the lightness (DL GM, P = 0.05), degree of yellow hue (DL and DH LL, P = 0.01), oxygenated lean color (DL GM, P = 0.004), uniformity (DH GM, P = 0.03, and DH LL, P = 0.06), and overall color stability of the product from d 3 through 9 of retail display. The percent surface discoloration (DL and DH GM, P = 0.04, and DL and DH LL, P < 0.0001), degree of browning (DL and DH GM, P = 0.002, and DL and DH LL, P < 0.0001), and discoloration (DL and DH GM, P = 0.01, and DH LL, P = 0.05) of the product was decreased. The DL GM steaks were juicier (P = 0.07), more acceptable (P = 0.05), and more satisfying (P = 0.01) than the control steaks. Seventy-seven percent of panelists would purchase the DL GM product (control, 61%, and DH, 60%). In conclusion, 55 d of rumen-protected HIS treatment positively impacts consumer perception and may optimize product quality and marketability in beef cattle. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate whether administration of L-Gln would affect mediators of acute phase response in postparturient dairy cows. Twenty-four multiparous Holstein cows were blocked by the expected day of calving and randomly assigned to 1 of the 3 treatment groups (n = 8/group): 1) i.v. infusion of 10 L of 0.85% NaCl (control), 2) i.v. infusion of 106, or 3) 212 g/d of L-Gln mixed with 10 L of 0.85% NaCl solution; each treatment was given 8 h/d for each of 7 consecutive days starting on d 1 after calving. Blood samples were collected 1 wk before the expected day of parturition as well as on d 0, 7, 14, and 21 after parturition; plasma concentrations of serum amyloid A (SAA), haptoglobin, and lipopolysaccharide-binding protein were measured by ELISA, and α1-acid glycoprotein was assessed by radial immunodiffusion. Concentrations of SAA, haptoglobin, and α1-acid glycoprotein increased in control cows after parturition, reaching peak values on d 0 or 7 postpartum (60, 1,093, and 963 µg/mL, respectively). Cows infused with 106 g/d of L-Gln had greater concentrations of SAA in plasma on d 14 and 21 compared with controls (62.8 vs. 30.2 and 71.1 vs. 34.5 µg/mL, respectively). Cows infused with 212 g/d of L-Gln had greater concentrations of SAA on d 7 (82.5 vs. 53.9 µg/mL) and lower concentrations of haptoglobin on d 14 and 21 postpartum compared with controls (264 vs. 621 and 175 vs. 587 µg/mL, respectively). Cows treated with 106 and 212 g/d of L-Gln had greater plasma lipopolysaccharide-binding protein concentrations on d 7 compared with control group (50.0 and 35.6 vs. 10.8 µg/mL, respectively). There were no treatment differences with respect to milk yield and DM intake during the experimental period. In conclusion, our data indicate that i.v. administration of L-Gln modulated acute phase mediators in dairy cows after parturition and warrants further research into the mechanisms behind these effects. [ABSTRACT FROM AUTHOR]

Approximately 90% of beef cattle on feed in the United States receive at least one anabolic implant, which results in increased growth, efficiency, and economic return to producers. However, the complete molecular mechanism through which anabolic implants function to improve skeletal muscle growth remains unknown. This study had 2 objectives: (1) determine the effect of polyamines and their precursors on proliferation rate in bovine satellite cells (BSC); and (2) understand whether trenbolone acetate (TBA), a testosterone analog, has an impact on the polyamine biosynthetic pathway. To address these, BSC were isolated from 3 finished steers and cultured. Once cultures reached 75% confluency, they were treated in 1% fetal bovine serum (FBS) and/or 10 nM TBA, 10 mM methionine (Met), 8 mM ornithine (Orn), 2 mM putrescine (Put), 1.5 mM spermidine (Spd), or 0.5 mM spermine (Spe). Initially, a range of physiologically relevant concentrations of Met, Orn, Put, Spd, and Spe were tested to determine experimental doses to implement the aforementioned experiments. One, 12, or 24 h after treatment, mRNA was isolated from cultures and abundance of paired box transcription factor 7 (Pax7), Sprouty 1 (Spry), mitogen-activated protein kinase-1 (Mapk), ornithine decarboxylase (Odc), and S adenosylmethionine (Amd1) were determined, and normalized to 18S. No treatment × time interactions were observed (P ≥ 0.05). Treatment with TBA, Met, Orn, Put, Spd, or Spe increased (P ≤ 0.05) BSC proliferation when compared with control cultures. Treatment of cultures with Orn or Met increased (P ≤ 0.01) expression of Odc 1 h after treatment when compared with control cultures. Abundance of Amd1 was increased (P < 0.01) 1 h after treatment in cultures treated with Spd or Spe when compared with 1% FBS controls. Cultures treated with TBA had increased (P < 0.01) abundance of Spry mRNA 12 h after treatment, as well as increased mRNA abundance of Mapk (P < 0.01) 12 h and 24 h after treatment when compared with 1% FBS control cultures. Treatment with Met increased (P < 0.01) mRNA abundance of Pax7 1 h after treatment as compared with 1% FBS controls. These results indicate that treatments of BSC cultures with polyamines and their precursors increase BSC proliferation rate, as well as abundance of mRNA involved in cell proliferation. In addition, treatment of BSC cultures with TBA, polyamines, or polyamine precursors impacts expression of genes related to the polyamine biosynthetic pathway and proliferation., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Our objectives were to determine the effect of post rigor calcium chloride injection or freezing on 1) sarcoplasmic calcium concentration and calpain-2 activity of beef longissimus lumborum (LL) and semimembranosus (SM) steaks aged 1, 4, and 14days post-treatment and on 2) Warner-Bratzler shear force, water holding capacity, and consumer acceptability of LL and SM steaks aged 4 and 14days post-treatment. Free calcium levels in the calcium, frozen, and control steaks averaged 1256, 127, and 121μM for the LL and 1520, 120, and 111μM for the SM, respectively. Measurable LL native calpain-2 activity was lower in calcium and frozen steaks than control steaks (P<0.01), while SM native calpain-2 activity was lowest in calcium steaks and intermediate in frozen steaks (P<0.01). LL calcium steaks were more tender (P=0.04) than control steaks. In conclusion, calcium chloride injection and freezing activate calpain-2 earlier postmortem in both muscles and calcium injection improves LL tenderness., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

We hypothesized that variable composition in finishing rations, more specifically; the proportion of potato-by-product (PBP) and rumen protected histidine (His) supplementation may influence growth and meat quality attributes. Two different diets were fed (1) finishing ration with corn and barley as grains (CB, n = 20) and (2) substitution of 10% corn, DM basis, with PBP (PBP, n = 20). Additionally, half of each dietary treatment received 50 g/hd/d rumen protected His (HS, n= 20) while the other half received no supplement (NS, n = 20). Inclusion of 10% PBP or HS did not affect growth or carcass traits. Color stability was analyzed using Hunter color values as well as AMSA visual appraisal in both longissimus thoracis (LT) and gluteus medius (GM) muscles. The LT, but not the GM, of CB steers was more color stable over a 9 d simulated retail display compared to those fed a PB diet. Steers receiving HS produced significantly (P < 0.05) more color stable LT and GM steaks., (Copyright © 2015 Elsevier Ltd. All rights reserved.)