Paraspinous Muscle Flaps in Complex Pediatric Spine Surgeries: A 12-Year Single Institution Experience

PURPOSE

The benefits of paraspinous flaps in adult complex spine surgery patients are established in the literature; however, their use in pediatric patients has not been well described. This study compares clinical outcomes with and without paraspinous muscle flap closure in pediatric patients who have undergone spine surgery.

METHODS

We conducted a retrospective review of all pediatric spine surgeries at the University of California, San Francisco from 2011 to 2022. Patients were divided into 2 cohorts based on whether the plastic surgery service closed or did not close the wound with paraspinous muscle flaps. We matched patients by age, American Society of Anesthesiology classification, prior spinal surgical history, and diagnosis. Surgical outcomes were compared between the 2 cohorts.

RESULTS

We identified 226 pediatric patients who underwent at least one spinal surgery, 14 of whom received paraspinous flap closure by plastic surgery. They were matched in a 1:4 ratio with controls (n = 56) that did not have plastic surgery closure. The most common indication for plastic surgery involvement was perceived complexity of disease by the spine surgeon with concern for inadequate healthy tissue coverage (78.6%), followed by infection (21.4%). Postoperative complications were similar between the two groups. The plastic surgery cohort had a higher rate of patients who were underweight (57.1% vs 14.3%, P < 0.01) and had positive preoperative wound cultures (28.6% vs 8.9%, P = 0.05), as well as a higher rate of postoperative antibiotic usage (78.6 vs 17.9%, P < 0.01). There was no difference in recorded postoperative outcomes.

CONCLUSIONS

Spine surgeons requested paraspinous flap closure for patients with more complex disease, preoperative infections, history of chemotherapy, or if they were underweight. Patients with paraspinous flap coverage did not have increased postoperative complications despite their elevated risk profile. Our findings suggest that paraspinous muscle flaps should be considered in high-risk pediatric patients who undergo spine surgery.

Soft Tissue Reconstruction After Sacral Neoplasm Resection: The University of California San Francisco Experience

PURPOSE

Resection of sacral neoplasms such as chordoma and chondrosarcoma with subsequent reconstruction of large soft tissue defects is a complex multidisciplinary process. Radiotherapy and prior abdominal surgery play a role in reconstructive planning; however, there is no consensus on how to maximize outcomes. In this study, we present our institution's experience with the reconstructive surgical management of this unique patient population.

METHODS

We conducted a retrospective review of patients who underwent reconstruction after resection of primary or recurrent pelvic chordoma or chondrosarcoma between 2002 and 2019. Surgical details, hospital stay, and postoperative outcomes were assessed. Patients were divided into 3 groups for comparison based on reconstruction technique: gluteal-based flaps, vertical rectus abdominus myocutaneous (VRAM) flaps, and locoregional fasciocutaneous flaps.

RESULTS

Twenty-eight patients (17 males, 11 females), with mean age of 62 years (range, 34-86 years), were reviewed. Twenty-two patients (78.6%) received gluteal-based flaps, 3 patients (10.7%) received VRAM flaps, and 3 patients (10.7%) were reconstructed with locoregional fasciocutaneous flaps. Patients in the VRAM group were significantly more likely to have undergone total sacrectomy (P < 0.01) in a 2-stage operation (P < 0.01) compared with patients in the other 2 groups. Patients in the VRAM group also had a significantly greater average number of reoperations (2 ± 3.5, P = 0.04) and length of stay (29.7 ± 20.4 days, P = 0.01) compared with the 2 other groups. The overall minor and major wound complication rates were 17.9% and 42.9%, respectively, with 17.9% of patients experiencing at least 1 infection or seroma. There was no association between prior abdominal surgery, surgical stages, or radiation therapy and an increased risk of wound complications.

CONCLUSIONS

Vertical rectus abdominus myocutaneous flaps are a more suitable option for patients with larger defects after total sacrectomy via 2-staged anteroposterior resections, whereas gluteal myocutaneous flaps are effective options for posterior-only resections. For patients with small- to moderate-sized defects, local fasciocutaneous flaps are a less invasive and effective option. Paraspinous flaps may be used in combination with other techniques to provide additional bulk and coverage for especially long postresection wounds. Furthermore, mesh is a useful adjunct for any reconstruction aimed at protecting against intra-abdominal complications.

The Utility of Prevena Negative Pressure Wound Therapy on Groin Incisions for Critical Limb-Threatening Ischemia: A Single Institution Experience

BACKGROUND

Incisional negative pressure wound therapy (iNPWT) is an adjunctive treatment that uses constant negative pressure suction to facilitate healing. The utility of this treatment modality on vascular operations for critical limb-threatening ischemia (CLTI) has yet to be elucidated. This study compares the incidence of postoperative wound complications between the Prevena Incision Management System, a type of iNPWT, and standard wound dressings for vascular patients who also underwent plastic surgery closure of groin incisions for CLTI.

METHOD

We performed a retrospective cohort study of 40 patients with CLTI who underwent 53 open vascular surgeries with subsequent sartorius muscle flap closure. Patient demographics, intraoperative details, and wound complications were measured from 2015 to 2018 at the University of California San Francisco. Two cohorts were generated based on the modality of postoperative wound management and compared on wound healing outcomes.

RESULTS

Of the 53 groin incisions, 29 were managed with standard dressings, and 24 received iNPWT. Patient demographics, comorbidities, and operative characteristics were similar between the 2 groups. Patients who received iNPWT had a significantly lower rate of infection (8.33% vs 31.0%, P = 0.04) and dehiscence (0% vs 41.3%, P < 0.01). Furthermore, the iNPWT group had a significantly lower rate of reoperation (0% vs 17.2%, P = 0.03) for wound complications within 30 days compared with the control group and a moderately reduced rate of readmission (4.17% vs 20.7%, P = 0.08).

CONCLUSIONS

Rates of infection, reoperation, and dehiscence were significantly reduced in patients whose groin incisions were managed with iNPWT compared with standard wound care. Readmission rates were also decreased, but this difference was not statistically significant. Our results suggest that implementing iNPWT for the management of groin incisions, particularly in patients undergoing vascular operations for CLTI, may significantly improve clinical outcomes.

Tertiary lymphoid structures sustain cutaneous B cell activity in hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic skin condition affecting approximately 1% of the US population. HS skin lesions are highly inflammatory and characterized by a large immune infiltrate. While B cells and plasma cells comprise a major component of this immune milieu, the biology and the contribution of these cells in HS pathogenesis are unclear. We aimed to investigate the dynamics and microenvironmental interactions of B cells within cutaneous HS lesions. Combining histological analysis, single-cell RNA sequencing, and spatial transcriptomics profiling of HS lesions, we defined the tissue microenvironment relative to B cell activity within this disease. Our findings identified tertiary lymphoid structures (TLSs) within HS lesions and described organized interactions among T cells, B cells, antigen-presenting cells, and skin stroma. We found evidence that B cells within HS TLSs actively underwent maturation, including participation in germinal center reactions and class switch recombination. Moreover, skin stroma and accumulating T cells were primed to support the formation of TLSs and facilitate B cell recruitment during HS. Our data definitively demonstrated the presence of TLSs in lesional HS skin and point to ongoing cutaneous B cell maturation through class switch recombination and affinity maturation during disease progression in this inflamed nonlymphoid tissue.

Tertiary Lymphoid Structures Sustain Cutaneous B cell Activity in Hidradenitis Suppurativa

Background

Hidradenitis suppurativa (HS) skin lesions are highly inflammatory and characterized by a large immune infiltrate. While B cells and plasma cells comprise a major component of this immune milieu the biology and contribution of these cells in HS pathogenesis is unclear.

Objective

We aimed to investigate the dynamics and microenvironmental interactions of B cells within cutaneous HS lesions.

Methods

We combined histological analysis, single-cell RNA-sequencing (scRNAseq), and spatial transcriptomic profiling of HS lesions to define the tissue microenvironment relative to B cell activity within this disease.

Results

Our findings identify tertiary lymphoid structures (TLS) within HS lesions and describe organized interactions between T cells, B cells, antigen presenting cells and skin stroma. We find evidence that B cells within HS TLS actively undergo maturation, including participation in germinal center reactions and class switch recombination. Moreover, skin stroma and accumulating T cells are primed to support the formation of TLS and facilitate B cell recruitment during HS.

Conclusion

Our data definitively demonstrate the presence of TLS in lesional HS skin and point to ongoing cutaneous B cell maturation through class switch recombination and affinity maturation during disease progression in this inflamed non-lymphoid tissue.

Long-distance transit alters liver and skeletal muscle physiology of beef cattle

Transportation of cattle is necessary but negatively impacts animal health and production efficiency. To gain a better understanding of the physiological responses to long-distance road transit, 36 crossbred beef steers (324 ± 36 kg) were randomly assigned to treatments (n = 12 steers/treatment): no transit and ad libitum access to feed and water (CON), no transit but deprived of feed and water for 18 h (DEPR), or road transit and no access to feed or water for 18 h (1 790 km; TRANS). Blood, liver, and muscle (longissimus dorsi) samples were collected pre- and post-treatment for analysis of blood metabolites, blood leukocyte profiles, blood markers of oxidative stress, and tissue antioxidant enzyme activity. Additionally, discovery-based metabolomics and proteomics analyses were performed on tissue samples collected immediately post-treatment (d 1). Data (except for omics) were analyzed using ProcMixed of SAS 9.4 with the fixed effect of treatment and steer as the experimental unit. Omics data were analyzed using MetaboAnalyst; metabolites and proteins of interest were identified based on a fold change threshold of 1.20 and t-test P-value of 0.10. On d 1, percent of pretreatment BW and DM intake were least for TRANS steers (P ≤ 0.06). Percent of pretreatment BW remained lesser for TRANS steers on d 8 (P = 0.05). Serum haptoglobin was greatest for TRANS steers immediately post-treatment (P = 0.02). Additionally, TRANS steers exhibited the greatest increase in the neutrophil to lymphocyte ratio and serum non-esterified fatty acids during the treatment period (P < 0.01), indicating TRANS steers experienced a more robust inflammatory and neuroendocrine response. Immediately post-treatment, liver superoxide dismutase activity tended to be greatest for both DEPR and TRANS (P = 0.07) while muscle superoxide dismutase activity was only greatest for TRANS (P = 0.02), suggesting TRANS steers may have experienced more oxidative stress due to the additional physical effort required to stand and maintain balance during transit. The abundance of several proteins (alpha-2-HS-glycoprotein) and metabolites (lactate, citrate, tri-hydroxybutyric acid, and leucine) associated with energy metabolism were altered in the liver and muscle of TRANS. The differential responses for DEPR versus TRANS steers indicate muscle plays an important role in how cattle respond to and recover from transportation stress.

Prophylactic Muscle Flaps in Primary Vascular Procedures of the Groin

BACKGROUND

Complications following vascular procedures involving the groin can lead to significant morbidity. Achieving stable soft tissue coverage over sites of revascularization can help mitigate complications. Prior evidence supports the use of muscle flaps in reoperative groins and in high risk patient populations to reduce postoperative complications. Data regarding the use of prophylactic muscle flap coverage of the groin is lacking. Therefore, the purpose of this study is to evaluate the effect of immediate prophylactic muscle flap coverage of vascular wounds involving the groin.

METHODS

A retrospective cohort study was performed on all patients undergoing primary open vascular procedures involving the groin for occlusive, aneurysmal, or oncologic disease between 2014 and 2020 at a single institution where plastic surgery was involved in closure. Patient demographics, comorbidities, surgical details, and postoperative complications were compared between patients who had sartorius muscle flap coverage of the vascular repair versus layered closure alone.

RESULTS

A total of 133 consecutive groins were included in our analysis. A sartorius flap was used in 115 groins (86.5%) and a layered closure was used in 18 (13.5%). Wound breakdown was similar between groups (25.2% sartorius vs. 38.9% layered closure, P = 0.26). However, the rate of reoperation was significantly higher in the layered closure group (50.0% vs. 12.2%, P < 0.01). Among patients who experienced wound breakdown (N = 36), a larger proportion of layered closure patients required operative intervention (71.4% vs. 20.7%, P = 0.02). Other rates of complications were not statistically different between groups.

CONCLUSIONS

In patients undergoing primary open vascular procedures involving the groin, patients who underwent prophylactic sartorius muscle flap closure had lower rates of reoperation. Although incisional breakdown was similar between the groups overall, the presence of a vascularized muscle flap overlying the vascular repair was associated with reduced need for reoperation and allowed more wounds to be managed with local wound care alone. Consideration should be given to this low morbidity local muscle flap in patients undergoing vascular procedures involving the groin.

Composite Vascularized Autograft Elbow Transplant: A Case Report

CASE

A 37-year-old man presented with an absent right elbow joint secondary to trauma, subsequent ankylosis, total elbow arthroplasty (TEA), and TEA explantation after infection. The patient also had a contralateral complete brachial plexus injury, but an intact elbow joint. Given that the patient had a functional right hand/wrist, composite vascularized autograft elbow transplant was performed from left to right upper extremity. Four years postoperatively, the patient could independently complete activities of daily living.

CONCLUSION

This case is the first to report composite vascularized autograft elbow transplant. Although indications are limited, this case illuminates novel uses of standard techniques for a difficult problem.

Mycotic aneurysm of the distal radial artery after cardiac catheterisation

A mycotic aneurysm of the distal radial artery following access for cardiac catheterisation is a rare complication that has not been described in the literature. We present the case of an 84-year-old man who developed bacteraemia and cellulitis over his left first dorsal webspace 2 days after undergoing cardiac catheterisation through the distal radial artery at the anatomic snuffbox. Ultrasound scanning and CT imaging were concerning for a possible pseudoaneurysm at that location. Once we confirmed that the patient had adequate flow through his hand with angiography and an Allen's test, we explored his left hand and found a mycotic aneurysm of the distal radial artery with surrounding frank purulence. We resected the aneurysm and ligated the artery. Pathology confirmed that this was a mycotic aneurysm. The patient quickly recovered from his infection after this definitive treatment.

Vascularized Bone Grafts for Spinal Fusion-Part 4: The Scapula

BACKGROUND

Solid arthrodesis is the long-term goal of most spinal reconstruction surgeries. A multitube of biologics as well as autograft is commonly used to augment the bony fusion. Medial scapular vascularized bone grafts (S-VBGs) are a novel approach to supplement cervicothoracic arthrodesis in patients at high risk for failed fusion.

OBJECTIVE

To discuss the benefits of using a vascularized scapular graft, pedicled to the rhomboid minor, compared to both nonvascularized bone grafts and free vascularized bone grafts, as well as the surgical technique, feasibility, and nuances of the surgical experience with an S-VBG.

METHODS

The anatomic feasibility of this procedure has been established in cadaver studies. This technical note details the operative steps and presents the first surgery in which a vascularized scapular graft was used to supplement cervicothoracic arthrodesis.

RESULTS

A single patient with complex cervical deformity was successfully treated with this novel arthrodesis approach.

CONCLUSION

Vascularized scapula grafts, pedicled on the rhomboid minor, provides both structural support and a source of vascularized autograft to a cervicothoracic arthrodesis. It leverages the benefits of a free-flap bone with less operative time and morbidity.

The Historical Role of the Plastic Surgeon in Spine Reconstruction

Wound complications occur in up to 19% of patients undergoing complex spine surgery. The role of the plastic surgeon in complex and redo spine surgery is important and evolving. Classically, plastic surgeons have been involved in the management of patients who develop wound complications following surgery. This involves reconstruction of posterior trunk defects with locoregional fasciocutaneous, muscle, and free tissue transfers. There has also been an increasing role for plastic surgeons to become involved in prophylactic closures of complex and/or redo spine surgeries for high-risk populations. Identification of patients with comorbidities and likelihood for multiple reoperations who are prophylactically treated with complex closure with or without local muscle flaps could significantly decrease the postoperative wound complications.

Satellite cell activation and retention of muscle regenerative potential after long-term denervation

Irreversible denervation atrophy remains an unsolved clinical problem, and the role of skeletal muscle stem cell (MuSC, satellite cell) depletion in this process is unclear. We investigated the ability of MuSCs to regenerate muscle in the context of denervation. Three to 12 months following sciatic denervation in mice, MuSC number, size, EdU uptake, rate of division, and mitochondrial activity were increased. Following acute myotoxin injury, denervated muscles formed new muscle fibers in situ. MuSCs isolated via flow cytometry from denervated mouse muscle, or from atrophic denervated gluteus maximus muscles of humans with complete spinal cord injuries two decades prior, formed new muscle fibers and reoccupied the anatomic niche after transplantation into uninjured muscle. Our results show unequivocally that, even after prolonged denervation, MuSCs retain intrinsic regenerative potential similar to that of uninjured MuSCs. Treatment of denervation atrophy will require elucidating the non-MuSC environmental changes in muscle that prevent functional regeneration.

Effects of physical preparation of diets and inclusion rate of modified wet distillers grains with solubles on production and rumen measurements of lactating dairy cows

Our objective was to determine if methods for preparing total mixed ration [TMR; horizontal paddle mixer with knives (PK) vs. vertical auger (VA) mixer] would alter the physical form of the TMR and affect utilization of diets with increasing amounts of modified wet distillers grains with solubles (MWDGS). Holstein cows (n = 24 with 12 ruminally cannulated; 144 d in milk ± 31 d at start) were used in a split-plot design with mixer type as the whole plot and MWDGS concentrations as subplots in a replicated 3 × 3 Latin square arrangement with 35-d periods. Inclusion rates of MWDGS were 10, 20, and 30% of dietary dry matter, primarily replacing corn, soybean meal, soyhulls, and whole cottonseed. Feed dry matter intake (DMI) was less for PK (23.8 kg/d) than for VA (25.7 kg/d), but was unaffected by MWDGS concentration. Milk production did not differ by concentration of MWDGS or by interaction of MWDGS × mixer. Milk fat percentage declined with increasing MWDGS but the interaction between mixer and MWDGS showed that decreases were larger with VA mixing. Cows fed the diet containing 30% MWDGS mixed with PK averaged 3.45% (1.24 kg/d) milk fat, whereas cows fed the same diet mixed with VA averaged 2.81% (1.10 kg/d) fat. Concentrations of trans-10,cis-12 C18:2 in milk fat likely explain the differences observed in milk fat yield; the concentration of trans-10,cis-12 C18:2 increased as MWDGS was increased and the MWDGS × mixer interaction showed that VA had greater concentrations. Greater mean particle size and increased variation in particle size with VA may partially explain differences in milk fat via increased sorting that allowed for an altered rumen environment and favored alternative biohydrogenation pathways. Feed conversion efficiency (FCE; energy-corrected milk/DMI) decreased linearly as MWDGS increased, but FCE tended to be maintained when higher MWDGS diets were mixed using PK rather than VA. Ruminal pH and ammonia concentration decreased linearly as MWDGS increased. The PK mixer resulted in greater FCE when higher amounts of MWDGS were fed, primarily because milk fat content and yield were not as depressed and DMI was lower at similar milk yields.

Immunopathogenesis of hidradenitis suppurativa and response to anti-TNF-α therapy

Hidradenitis suppurativa (HS) is a highly prevalent, morbid inflammatory skin disease with limited treatment options. The major cell types and inflammatory pathways in skin of patients with HS are poorly understood, and which patients will respond to TNF-α blockade is currently unknown. We discovered that clinically and histologically healthy appearing skin (i.e., nonlesional skin) is dysfunctional in patients with HS with a relative loss of immune regulatory pathways. HS skin lesions were characterized by quantitative and qualitative dysfunction of type 2 conventional dendritic cells, relatively reduced regulatory T cells, an influx of memory B cells, and a plasma cell/plasmablast infiltrate predominantly in end-stage fibrotic skin. At the molecular level, there was a relative bias toward the IL-1 pathway and type 1 T cell responses when compared with both healthy skin and psoriatic patient skin. Anti–TNF-α therapy markedly attenuated B cell activation with minimal effect on other inflammatory pathways. Finally, we identified an immune activation signature in skin before anti–TNF-α treatment that correlated with subsequent lack of response to this modality. Our results reveal the fundamental immunopathogenesis of HS and provide a molecular foundation for future studies focused on stratifying patients based on likelihood of clinical response to TNF-α blockade.

Hidradenitis suppurativa lesions are characterized by alterations in cDC2s, relatively reduced Tregs, an influx of memory B cells and plasma cells, and biases towards IL1 pathway activation and type 1 T cell responses.

0803 Clinical and Polysomnographic Features of Trauma Associated Sleep Disorder (TASD)

Introduction

Trauma associated sleep disorder (TASD) is an emerging parasomnia that develops after trauma with clinical features of trauma related nightmares (TRN), disruptive nocturnal behaviors (DNB), and autonomic disturbances. The purpose of this study is to characterize the clinical and polysomnographic (PSG) features of TASD.

Methods

Clinical history and detailed video-PSG review, to include post-PSG nightmare reports, of a cohort of patients with TASD.

Results

Patients (n=40, 32 men, 8 women) were active duty service members with a median age of 38.9 yrs (range 24-57 yrs). Dream content typically related to combat (n=37, 92.5%), with 75% (n=30) reporting TRN and 60% (n=24) reporting dream enactment at least weekly. Self-reported DNB included vocalizations, violent limb movements, thrashing, defensive posturing, and jumping from bed. There was a high rate of comorbid insomnia (n=35, 87.5%), PTSD (n=23, 63.9%), anxiety (n=25, 62.5%), depression (n=20, 50%), OSA (n=19, 47.5%), chronic pain (n=12, 30%), and TBI (n=13, 32.5%). Most patients had REM sleep without atonia (RSWA) (n=33, 82.5%), though a minority had purposeful DNB (n=11, 27.5%). Vocalizations were present in seven (17.5%) patients. Patients with PTSD were more likely to have purposeful DNB (n=9, 100%) than those without PTSD (n=13, 50%; p=0.013), whereas patients with purposeful DNB had markedly less N3 sleep (1.0±11.4%) than those without purposeful DNB (13.8±16.2%; p=0.002). There was no significant difference in medications between DNB groups.

Conclusion

TASD is frequently comorbid with other sleep and behavioral health disorders. Characteristics of TASD are often captured on video-PSG during REM sleep, though DNB may be less pronounced than what patients report in their habitual sleeping environment. Clinical and video-PSG correlations are invaluable in assessing patients with TASD. This study, which is the largest cohort to date, provides a further basis for establishing TASD as a unique REM-related parasomnia.

Support

N/A

Free Tissue Transfer Optimizes Stump Length and Functionality Following High-Energy Trauma

Background Advances in medicine and surgery have allowed patients, who in the past would have required more aggressive amputations, to maintain longer stump lengths. Microvascular free tissue transfer has become increasingly popular to preserve limb length and optimize functionality. We present our experience using microvascular free flap reconstruction to preserve lower extremity limb length in the setting of high-energy trauma.

Methods We conducted an Institutional Review Board-approved retrospective review of patients at three San Francisco hospitals who underwent free flap reconstruction after high-energy trauma between 2003 and 2015. We included all patients who underwent free flap reconstruction for lower extremity limb length preservation. We reviewed patient demographics, preoperative variables, intraoperative details, and postoperative outcomes, including complications, functional status, reoperation rates, and need for revision amputation.

Results Twelve patients underwent microvascular free tissue transfer for limb length preservation. Overall, the patients had similar preoperative comorbidities and a mean age of 44. Six patients had postoperative complications: three minor complications and three major complications. Seven patients had additional surgeries to improve the contour of the flap. One patient required revision amputation, while the remaining 11 patients preserved their original limb length. The majority of patients were fully ambulatory, and four used a prosthesis.

Conclusion Microvascular free tissue transfer can be used to effectively maintain lower extremity stump length following trauma. Although these patients often require multiple surgeries and face lengthy hospital courses, this technique enables preservation of a functional extremity that would otherwise require a more proximal amputation.

Effect of trace mineral source on mineral status and performance of beef steers fed low- or high-sulfur diets

A 2 × 2 factorial assessed the effect of trace mineral (TM) sources fed within low- or high-S diets on the mineral status and performance of cattle. Angus crossbred steers ( = 48; 6/pen) were blocked by BW (316 ± 16.6 kg), assigned to low-S (0.27%; LS) or high-S (0.54%; HS; added as CaSO) diets, and supplemented TM at 10 mg Cu, 30 mg Zn, and 20 mg Mn/kg DM from hydroxy (HYD; IntelliBond; Micronutrients USA LLC, Indianapolis, IN) or inorganic (sulfates; ING) sources ( = 12 steers/treatment). Steers were fed corn silage and corn-based diets via GrowSafe bunks in the growing period (GP; 84 d) and finishing period (FP; 77 d), respectively. Plasma and liver were collected at trial initiation and end of GP and FP for mineral concentrations. End of GP and FP red blood cell lysate superoxide dismutase (SOD) and Mn-SOD activity and liver glutathione concentrations were measured. Data were used as a 2 × 2 factorial using Proc Mixed of SAS (SAS Inst. Inc., Cary, NC) with initial plasma and liver status analyzed as covariates. High S decreased ( < 0.01) liver Cu and tended ( ≤ 0.10) to decrease plasma Cu concentrations. Liver Cu concentrations were lower in HYD than ING in the FP ( < 0.01). High S decreased ( = 0.04) GP plasma Zn concentrations and tended to decrease ( = 0.10) GP liver Zn. There were GP ( = 0.05) and FP ( = 0.02) S × TM effects for liver Mn concentrations where GP LS-HYD was greater than all other treatments, whereas FP LS-HYD was lower than HS-HYD and LS-ING and FP HS-ING was less than LS-ING. Glutathione, SOD, and Mn-SOD were not different ( ≥ 0.13) in the GP, but S × TM tended to affect FP Mn-SOD ( = 0.10), where LS-HYD tended to be lower than LS-ING. Oxidized glutathione in FP tended to be lower ( = 0.06) for HYD than ING. In the GP, there were S × TM effects on performance where LS-HYD had greater ADG and G:F ( ≤ 0.05) than HS-HYD, whereas LS and HS-ING were intermediate. For FP performance S × TM effects were noted where LS-HYD and HS-ING tended ( = 0.10) to gain more than HS-HYD and HS-HYD had lower G:F ( = 0.04) than HS-ING. There were no effects of S × TM on final BW, DMI, or ADG ( ≥ 0.11); however, HS-HYD had lower G:F than other treatments overall ( = 0.05). High S decreased back fat and yield grade ( = 0.03), and rib eye area was smaller for HYD than ING ( = 0.02). In this study HS decreased markers of Cu and Zn status, and differential effects of HYD vs. ING minerals were noted across dietary phases, although all steers maintained adequate TM status.

High-Yield Purification, Preservation, and Serial Transplantation of Human Satellite Cells

Investigation of human muscle regeneration requires robust methods to purify and transplant muscle stem and progenitor cells that collectively constitute the human satellite cell (HuSC) pool. Existing approaches have yet to make HuSCs widely accessible for researchers, and as a result human muscle stem cell research has advanced slowly. Here, we describe a robust and predictable HuSC purification process that is effective for each human skeletal muscle tested and the development of storage protocols and transplantation models in dystrophin-deficient and wild-type recipients. Enzymatic digestion, magnetic column depletion, and 6-marker flow-cytometric purification enable separation of 10⁴ highly enriched HuSCs per gram of muscle. Cryostorage of HuSCs preserves viability, phenotype, and transplantation potential. Development of enhanced and species-specific transplantation protocols enabled serial HuSC xenotransplantation and recovery. These protocols and models provide an accessible system for basic and translational investigation and clinical development of HuSCs.

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High-efficiency purification permits serial transplantation of human satellite stem cells

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Cryopreservation preserves satellite cell function and phenotype

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1 gram of adult skeletal muscle yields 10⁴ highly purified satellite cells

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Purified uncultured endogenous human satellite cells can be stored and shared

Influence of feed efficiency classification and growing and finishing diet type on meat tenderness attributes of beef steers

Enhancing feed efficiency (FE) in cattle continues to be an important goal in the beef industry. Previous research suggests improving FE may alter calpain system activity, potentially having negative effects on meat tenderness. The objective of this study was to assess the potential influence of beef cattle FE on postmortem meat tenderness. During the growing phase, 181 crossbred steers were fed for 76 d at the University of Missouri on a whole shell corn-based diet (MU-Corn; = 90) or a roughage-based diet (MU-Rough; = 91). Within diet, steers were classified for FE based on residual feed intake (RFI) calculations. Within each growing phase diet, the 12 most feed efficient (HFE; average RFI -3.33 ± 0.77) and 12 least feed efficient (LFE; average RFI 2.90 ± 0.94) steers (48 steers total) were selected and shipped to Iowa State University for the finishing phase. Steers were fed in pens with GrowSafe bunks and equally assigned to a cracked corn-based finishing diet (ISU-Corn) or a byproduct-based finishing diet (ISU-Byp) for the 87-d finishing phase. After a 24-h chill, rib sections were collected from all carcasses and aged for 2 or 14 d prior to analysis of calpastatin activity and calpain 1 autolysis (d 2), troponin-T degradation (d 2 and 14), proximate composition (d 2), and Warner-Bratzler shear force (WBSF; d 14). Data were analyzed as a 2 × 2 × 2 factorial, with steer or steak as the experimental unit ( = 6 per treatment combination). There were no 3- or 2-way interactions ( ≥ 0.12) noted for any data, with the exception of steak lipid content, which tended ( = 0.08) to be affected by FE × Iowa State University diet. Steaks from LFE steers had greater lipid content compared with steaks from HFE steers within ISU-Byp, with no differences due to FE within ISU-Corn. Growing diet did not affect calpastatin activity, calpain 1 autolysis, or troponin T degradation ( ≥ 0.12); however, MU-Rough had greater WBSF than MU-Corn ( = 0.05). Day-2 calpastatin activity tended ( = 0.10) to be greater in steaks from HFE vs. LFE steers, although no differences due to FE classification were observed for calpain 1 protein, troponin-T degradation, or WBSF ( ≥ 0.13). Finishing diet did not affect calpastatin activity, calpain 1 autolysis, d-2 troponin-T degradation, or WBSF ( ≥ 0.24); however, d-14 troponin-T degradation was greater in ISU-Corn than in ISU-Byp ( = 0.005). In this study, using phenotypic extremes for FE revealed a tendency for greater calpastatin activity only in highly feed-efficient steers; however, these data indicate that high-fiber diets may negatively impact meat tenderness, and further work is needed to clarify the influence of diet type on parameters of meat tenderness.

Effect of post-ethanol extraction sorghum silage as a forage source in growing and finishing diets on steer performance, carcass characteristics, and nutrient digestibility

Two experiments evaluated the use of post-ethanol extraction sorghum silage as an alternative forage source in feedlot diets. Seventy-two crossbred steers (397 kg [SD 23]) were used to evaluate growth and carcass characteristics. Steers were blocked by BW into pens of 6 steers and randomly assigned to growing diets containing 40% (DM basis) sorghum silage (SS; 57.6% NDF) or grass hay (CON; 63.3% NDF) for 56 d ( = 6 pens per treatment). Within each treatment, steers transitioned to dry-rolled corn-based finishing diets (fed for 56 d) containing 6% effective NDF contributed by the forage source, resulting in forage inclusions of 16% for SS and 13.1% for CON, where forage replaced corn. A subsample of steers ( = 12 per treatment) housed in pens equipped with GrowSafe bunks were used for determination of growing phase diet total tract digestibility. From d 28 to 42, steers received titanium dioxide at approximately 10 g∙steer∙d, and fecal samples were collected on d 41 and 42. Fecal and total mixed ration samples were dried and ground for analysis of DM, OM, NDF, ADF, CP, ether extract (EE), and starch. Data were analyzed with the MIXED procedure of SAS, with fixed effects of treatment and block for performance and carcass data or treatment for digestibility data; significance was determined at ≤ 0.05 and tendencies at ≤ 0.10. Growing phase DMI and ADG did not differ due to treatment ( ≥ 0.19); however, SS-fed steers had improved G:F compared with CON-fed steers ( = 0.04). Finishing period ADG and G:F did not differ ( ≥ 0.15) between treatments, despite SS-fed steers having lesser ( = 0.008) DMI than CON-fed steers. No differences in DMI, ADG, or G:F over the whole trial were noted between treatments ( ≥ 0.12) nor were any carcass traits affected ( ≥ 0.23). During the digestibility assessment period, DMI was less ( = 0.003) in SS-fed steers. Growing phase total tract apparent digestibility of DM and starch did not differ ( ≥ 0.19) due to treatment; however, OM digestibility tended to be greater ( = 0.09) in SS-fed steers. Steers fed SS had greater ( ≤ 0.03) digestibility of EE, CP, NDF, and hemicellulose than CON-fed steers. However, CON-fed steers had greater ( < 0.0001) ADF digestibility than SS-fed steers. These data suggest that postextraction sorghum silage can be effectively used in feedlot diets as an alternative forage source.

Influence of feed efficiency classification on diet digestibility and growth performance of beef steers

The diet digestibility and feed efficiency (FE) relationship is not well characterized in cattle. The study objective was to determine effects of growing phase FE and diet as well as finishing phase diet on diet digestibility and finishing phase FE. Two groups, totaling 373 crossbred steers, were fed for 70 d at the University of Missouri for the growing phase and then shipped to Iowa State University (ISU) for finishing. GrowSafe feed bunks were used during both the growing and the finishing phases. Steers were fed either growing phase whole shell corn (G-Corn) or growing phase roughage-based (G-Rough) diets. Within each group, the 12 greatest and 12 least feed efficient steers from each growing diet ( = 96 total; 48 steers/group; 488 ± 5 kg) were selected for further evaluation. At ISU, steers were fed an average of 10 g TiO/steer daily in receiving phase diets similar to growing diets for 15 d, with fecal grab samples collected on d 14 and 15 to determine diet DM digestibility during receiving (GDMdig). For finishing, steers were transitioned to byproduct-based diets (F-Byp) or corn-based diets (F-Corn) with 12 steers per growing-finishing diet combination per group. Optaflexx (200 mg/d) was fed for 28 d before harvest, and the TiO protocol was repeated immediately before introducing Optaflexx to determine diet DM digestibility during finishing (FDMdig). Data from the 2 groups (96 steers) were pooled, and steers were ranked by growing phase G:F and then classified as the 24 greatest feed efficient (HFE) or 24 least feed efficient (LFE) steers from each growing diet. Data were analyzed using PROC MIXED of SAS with group applied as a fixed effect. There was a positive correlation between GDMdig and FDMdig for steers fed nutritionally similar diets during both feeding phases, G-Rough/F-Byp steers ( = 0.68, < 0.01) and G-Corn/F-Corn steers ( = 0.49, = 0.02), but a negative correlation for G:F between phases in G-Rough/F-Corn steers ( = -0.57, < 0.01). Finishing G:F was greater in HFE steers versus LFE steers ( = 0.04), but there was no difference ( ≥ 0.5) in GDMdig or FDMdig due to FE classification. There was a positive correlation for DM digestibility between feeding phases when steers were grown and finished on similar diets. Overall, FE was repeatable but was negatively correlated between phases when steers were roughage grown and corn finished, reinforcing the idea that cattle should be FE tested using diet types similar to the production environment of interest.

The influence of supplemental Zn-amino acid complex and ractopamine hydrochloride feeding duration on growth performance and carcass characteristics of finishing beef cattle

Previous research indicates that finishing steer ADG and G:F increases linearly with increasing dietary Zn-amino acid complex (ZnAA) supplementation in cattle fed ractopamine hydrochloride (RAC). The objective of this study was to determine the influence of supplemental Zn-amino acid complex on growth performance and carcass characteristics of finishing steers fed RAC for 0, 28, or 42 d prior to harvest. This study was organized as 2 groups (GRP) of steers fed concurrently, for 91 (GRP 1) or 84 d (GRP 2). A total of 324 steers (463 ± 23.4 kg) were fed a corn-based finishing diet supplemented with 60 mg Zn/kg diet DM (as ZnSO). Steers were blocked by weight to pens of 6 steers, and assigned to receive either 0 (CON) or 60 mg supplemental Zn/kg DM from ZnAA ( = 27 pens per treatment). Receiving ZnAA for 49 (GRP 1) or 42 d (GRP 2) prior to start of RAC feeding had no impact on growth of steers ≥ 0.19). Forty-two d prior to harvest, pens were equally assigned within CON or ZnAA treatments to receive RAC at 300 mg∙steer∙d for 0 (NoRAC), 28 (28RAC), or 42 d (42RAC) prior to harvest, creating 6 final treatments ( = 9 pens per treatment). All steers within a GRP were harvested on the same day. Pen was the experimental unit, and the statistical model included the fixed effects of ZnAA, RAC, and block nested within GRP, and the random effect of pen. Ractopamine hydrochloride supplementation increased carcass-adjusted ADG, final BW, HCW, and ribeye area ( ≤ 0.007). There was an effect of ZnAA within 28RAC and 42RAC where carcass-adjusted ADG ( ≤ 0.10), and final BW and HCW ( ≤ 0.05) were greater in ZnAA supplemented vs. CON steers, and 28RAC steers supplemented with ZnAA had improved overall carcass-adjusted G:F relative to CON steers ( = 0.04). However, when steers did not receive RAC there was no effect of ZnAA on final BW, ADG, or HCW ( ≥ 0.78). Additionally, ZnAA supplementation had no effect on the difference in performance between steers supplemented with RAC for 28 vs. 42 d ( 0.21). In conclusion, under the conditions of this study supplemental ZnAA did not prevent the diminished response to RAC as days on RAC increased from 28 to 42. However, there appears to be a synergistic effect of ZnAA on RAC-induced cattle growth, as supplementing 60 mg Zn/kg DM from ZnAA to cattle fed RAC improved overall growth and HCW.

The effects of increasing supplementation of zinc-amino acid complex on growth performance, carcass characteristics, and inflammatory response of beef cattle fed ractopamine hydrochloride

Forty-two Angus crossbred steers (380 ± 5.3 kg) were enrolled in a finishing study to evaluate the influence of a supplemental Zn amino-acid complex (ZnAA; Availa-Zn) on performance and carcass characteristics of finishing steers in combination with ractopamine hydrochloride (RAC). Steers were stratified by BW into 7 pens of 6 steers each, and individual feed intake was measured. Steers were assigned to 1 of 4 treatments for 86 d (pre-RAC period): a dry-rolled corn-based diet supplemented with 60 mg Zn/kg DM from ZnSO and no supplemental ZnAA (CON; analyzed 88 mg Zn/kg DM; = 6) or CON diet supplemented with 30 (Zn30; = 12), 60 (Zn60; = 12), or 90 (Zn90; = 11) mg Zn/kg DM from ZnAA. Day 86 BW and G:F displayed a quadratic tendency ( = 0.09) with Zn60 steers being greater than the other treatments. Plasma cyclic adenosine monophosphate tended to linearly increase with increasing ZnAA ( = 0.10). On d 88, 6 of 12 steers (one of the 2 pens) receiving supplemental ZnAA was randomly selected to be supplemented with RAC at 300 mg∙steer∙d for the final 28 d of the experiment (RAC period). This created 7 final treatments: CON: no supplemental ZnAA, no RAC ( = 5); Zn30: Zn30, no RAC ( = 5); Zn30R: Zn30 + RAC ( = 6); Zn60: Zn60, no RAC ( = 6); Zn60R: Zn60 + RAC ( = 6); Zn90: Zn90, no RAC ( = 5); and Zn90R: Zn90 + RAC ( = 6). During the RAC period, as supplemental ZnAA increased within RAC-supplemented treatments, there was a linear increase in final BW, ADG, and G:F ( < 0.05). However, there was no effect of supplemental ZnAA on BW, ADG, or G:F during this period in non-RAC fed steers ( ≥ 0.44). Day 111 plasma Cu was increased, plasma Fe decreased, and leukocyte counts and serum interleukin-8 concentrations were greater ( < 0.05) in RAC-fed steers suggesting that RAC may elicit a mild inflammatory response. There was a tendency for increasing Zn supplementation to decrease plasma haptoglobin within RAC-fed steers ( = 0.07), suggesting that Zn may alter the inflammatory response. Overall, Zn60 improved growth performance during the pre-RAC period. Zinc supplemented as ZnAA appears to improve growth in combination with RAC supplementation, suggesting that Zn may enhance or support the biological function of RAC. Additionally, these results indicate that feeding RAC impacts trace mineral status, and potentially causes a non-specific inflammatory response, but further research is required to define this response.

Immunometabolic parameters in overweight dogs during weight loss with or without an exercise program

The influence of physical activity on metabolic health in overweight dogs is unknown. This study was conducted to evaluate biomarkers of immunometabolic health in relation to changes in physical activity and adiposity. Client-owned overweight dogs participated in a 12-wk intervention based on caloric restriction combined with a training program (fitness and diet [FD] group, n = 8), or caloric restriction alone (diet-only [DO] group, n = 8). Physical activity was monitored by accelerometry. All dogs were fed the same diet and achieved similar weight loss. Fasting blood samples were collected before and after 6- and 12-wk intervention. Insulin resistance was evaluated from plasma insulin and C-peptide as well as homeostasis model assessment. Inflammation and dyslipidemia were evaluated from circulating leptin, adiponectin, C-reactive protein (CRP), monocyte chemoattractant factor-1 (MCP-1), interleukin-8 (IL-8), and cholesterol. Accelerometer counts in both groups were high compared with previous reports of physical activity in overweight dogs. No difference in blood parameters was evident between groups, evaluated by linear mixed-effects model (P > 0.05). Within the groups, the following changes were significant by t-test (P < 0.05): leptin decreased in both groups. Within the FD group, IL-8, MCP-1, and CRP decreased at 6 wk and IL-8 and cholesterol at 12 wk. Within the DO group, C-peptide and HOMA decreased at 6 wk and C-peptide at 12 wk. We conclude that, for both groups, weight loss resulted in minor indications of improved immunometabolic health, whereas this level of physical activity did not add further benefits.

Effect of ferric ammonium citrate in feedlot diets with varying dried distillers' grains inclusion on ruminal hydrogen sulfide concentrations and steer growth

Angus-cross steers ( = 128) were used to examine the effects of supplementing ferric ammonium citrate (FAC; 300 mg ferric Fe/kg DM) to diets of 20, 40, or 60% dried distillers' grains plus solubles (DDGS) on growth performance, liver mineral and ruminal hydrogen sulfide (HS) concentrations, and carcass traits of finishing steers. Steers were blocked by initial BW (436 ± 10.6 kg) into pens of 4 and randomly assigned to 1 of 6 treatments ( = 5 or 6 pens per treatment) including a 20, 40, or 60% DDGS inclusion diet with (+) or without (-) 300 mg Fe/kg DM from FAC. Liver biopsies (d -9/-10 and 96) and HS measures (d 0, 7, 14, 21, and 95) were determined from 1 steer/pen. Steers were harvested on d 102 and carcass data were collected. A treatment × month effect ( ≤ 0.006) was noted for ADG and G:F, in which the 20-FAC ADG and feed efficiency were greater ( ≤ 0.02) between d 0 to 28 but lesser ( ≤ 0.04) from d 29 to 56 than that of the 20+FAC steers. Final BW linearly decreased ( < 0.01) as DDGS inclusion increased. Final BW tended to be greater ( = 0.10) in the 60+FAC steers than in the 60-FAC steers, whereas final BW was not different ( ≥ 0.32) due to FAC supplementation in the 20 or 40% DDGS diets. A quadratic effect was noted for DMI ( = 0.02), where 60% DDGS decreased DMI. Within the 20% DDGS diet FAC+ improved DMI ( = 0.03) but had no effect within 40 or 60% DDGS inclusion. Ruminal HS concentrations were not affected ( ≥ 0.25) by FAC, but increasing DDGS linearly increased ( < 0.01) ruminal HS values. Liver Cu was decreased ( < 0.01) by FAC across all DDGS inclusions and tended to linearly decrease ( = 0.06) with increasing DDGS inclusion, whereas liver Fe, Mn, and Zn were not altered ( ≥ 0.11) by DDGS inclusion. Liver Zn concentrations tended to be ( = 0.08) or were ( = 0.03) decreased by FAC supplementation within 20 and 40% DDGS, respectively. Increasing the inclusion of DDGS linearly decreased ( = 0.04) HCW and quadratically affected marbling score where the 40% DDGS had the greatest ( = 0.02) marbling scores. Supplementation of FAC within 60% DDGS improved ( ≤ 0.03) HCW and LM area. Marbling scores were greater ( ≤ 0.04) in 20+FAC and 40+FAC compared with 20-FAC and 40-FAC, respectively. In conclusion, although ruminal HS concentrations were not affected by FAC under the conditions of this study, supplementing FAC to diets containing 60% DDGS improved HCW and LM area, suggesting that FAC may be beneficial when dietary S concentrations exceed 0.5%.

Influence of growing phase feed efficiency classification on finishing phase growth performance and carcass characteristics of beef steers fed different diet types

A 5-yr study was conducted using 985 crossbred steers (464 kg [SD 32]) fed in 6 separate, replicated groups to determine the influence of growing phase (GP) feed efficiency (FE) classification and diet type on finishing phase (FP) FE of steers. During the GP at the University of Missouri, steers were fed either a whole shell corn-based diet (G-Corn; 528 steers) or a roughage-based diet (G-Rough; 457 steers) using GrowSafe feed bunks to measure DMI for 69 to 89 d. At the end of the GP, steers were ranked by residual feed intake (RFI) within diet, shipped to Iowa State University, and blocked into FP pens (5 to 6 steers/pen) by GP diet and RFI rank (upper, middle, or lower one-third). Steers were transitioned to either FP cracked corn- or byproduct-based diets and fed until 1.27 cm backfat was reached. After completion of the sixth group, average GP G:F within GP diet was calculated for each FP pen (168 total pens) using GP initial BW as a covariate (G-Corn: 0.207 [SD 0.038]; G-Rough: 0.185 [SD 0.036]). Pens were classified as highly feed efficient (HFE; >0.5 SD from the G:F mean; 58 pens), mid feed efficient (MFE; ±0.5 SD from the G:F mean; 60 pens), or lowly feed efficient (LFE; <0.5 SD from the G:F mean; 50 pens). Data were analyzed using PROC MIXED of SAS. Experimental unit was FP pen and the model included the fixed effects of GP diet, FE classification, FP diet, and the interactions. Group (1 to 6) was included as a fixed effect. There were no 3-way interactions ( ≥ 0.2) for any measured traits. Finishing phase G:F was not affected by any interactions ( ≥ 0.5) but was greater ( ≤ 0.03) for HFE versus MFE and LFE and greater ( = 0.02) for MFE versus LFE. Growing phase diet × FE classification effects were detected ( ≤ 0.01) for FP final BW (FBW), ADG, and DMI. Among G-Rough steers, HFE and MFE had greater ( ≤ 0.04) FBW and ADG than LFE, but among G-Corn steers, LFE had heavier ( = 0.03) FBW than HFE whereas ADG was unaffected ( ≥ 0.2) by FE classification. Dry matter intake was unaffected ( ≥ 0.3) by FE classification among G-Rough steers, but among G-Corn steers, LFE had greater ( ≤ 0.003) DMI than MFE and HFE. Overall, differences in FP G:F between FE classifications were driven by different factors depending on diet; ADG differed among roughage-grown steers and DMI differed among corn-grown steers. Ultimately, steers classified as HFE during the GP still had superior FE during the FP.

Relationship between antioxidant capacity, oxidative stress, and feed efficiency in beef steers

Feed efficiency (FE) can vary between individuals but sources of variation are not well characterized. Oxidative stress is among the biological mechanisms believed to contribute to variation. The objective of this study was to evaluate the relationship between FE, antioxidant activity, and oxidative stress in feedlot steers representing phenotypic extremes for FE. Crossbred beef steers ( = 181) fed 70-d growing phase (GP) whole-shell corn-based (G-Corn) or rye baleage and soybean hull-based (G-Rough) diets in GrowSafe bunks at the University of Missouri were shipped to Iowa State University where the 12 most feed efficient (HFE) and 12 least feed efficient (LFE) steers from each diet (n = 48; 467 kg [SD 51]) were selected for evaluation. Steers received diets similar to GP diets, and 3 d after arrival, blood was sampled to evaluate antioxidant activity and oxidative stress markers for the GP following transit. Steers were transitioned to finishing phase (FP) cracked corn-based (F-Corn) or dried distillers' grains and soybean hull-based (F-Byp) diets, and on FP d 97, blood samples for the FP were collected. Data for the GP were analyzed as a 2 × 2 factorial, and data for the FP were analyzed as a 2 × 2 × 2 factorial using PROC MIXED of SAS. No GP diet × FP diet, FP diet × FE group, or 3-way interactions were noted ( ≥ 0.11) for FP measures. Steers fed the G-Rough diet had greater ( = 0.04) GP plasma protein carbonyl concentrations. During the GP, HFE steers had greater ( ≤ 0.04) protein carbonyl and ratio of oxidized:reduced blood lysate glutathione concentrations than LFE steers. There were GP diet × FE group interactions ( ≤ 0.03) during the GP and FP. During the GP, total blood lysate superoxide dismutase (SOD) activity was greater ( ≤ 0.03) in G-Rough/LFE steers than in G-Rough/HFE and G-Corn/LFE steers; G-Corn/HFE steers were intermediate. The G-Rough/LFE steers had greater ( < 0.04) glutathione peroxidase (GPX) activity than other groups and greater ( = 0.03) plasma malondialdehyde concentrations than G-Corn/LFE steers. During the FP, the G-Rough/LFE steers had greater ( ≤ 0.04) GPX activity than G-Rough/HFE and G-Corn/LFE steers; G-Corn/HFE steers were intermediate. The F-Byp diet had greater ( < 0.01) protein carbonyl than the F-Corn diet, and no other FP diet effects were noted ( ≥ 0.3) for any FP measures. The GP diet and FE groups had stronger relationships with antioxidant activity and oxidative stress markers measured for the GP than for the FP. Overall, antioxidant activity may play a role in FE as LFE steers, driven largely by G-Rough/LFE steers, had greater SOD activity and GPX activity than HFE steers, potentially using a greater proportion of energy otherwise available for tissue accretion.

Effects of increased inclusion of algae meal on finishing steer performance and carcass characteristics

The deoiled residue from the production of heterotrophic microalgae can be combined with soyhulls to form a novel feedstuff called algae meal (ALG). To determine the effects of replacing corn in a finishing diet with ALG on growth, mineral status, carcass characteristics, and longissimus thoracis fatty acid profile, crossbred steers (168) were blocked by BW (432 ± 30.8 kg) into pens of 6 steers (7 pens per treatment). Pens received 1 of 4 diets: a corn-based control (CON), 14% ALG, 28% ALG (ALG28), and 42% ALG (ALG42). Corn was replaced by ALG on a DM basis. Steer BW were taken on d 0, 1, 28, 56, 74, 101, and 102, and steers were harvested on d 103. Pen was the experimental unit and DMI, ADG, and G:F data were analyzed as repeated measures. Two steers per pen were selected for sampling of blood and liver (d -1 and 96) and collection of rib steaks at harvest. There was a treatment by × time effect ( = 0.10) for overall DMI, where DMI linearly increased ( ≤ 0.008) across all time periods except Day 28 through, 56 when DMI was not different between ALG28 and ALG42. There was a treatment by time effect for ADG ( < 0.01), with ADG linearly decreasing ( ≤ 0.03) in the first and third month, not differing ( = 0.95) in the second month, and linearly increasing ( < 0.01) in the fourth month as ALG increased in the diet. Final BW and HCW did not differ ( ≥ 0.50) between CON- and ALG-fed cattle. There was a treatment × time effect for G:F ( < 0.01), with G:F linearly decreasing ( ≤ 0.01) in the first 3 mo as ALG increased in the diet, whereas G:F linearly increased ( < 0.01) in the fourth month. Based on steer performance, calculated dietary NEg linearly decreased ( < 0.01) as ALG increased in the diet. Yield grade linearly decreased ( = 0.02) and there was a tendency for dressing percent and 12th-rib back fat to linearly decrease ( ≤ 0.10) as ALG increased in the diet. Plasma Cu, Fe, and Mg concentrations were not different ( ≥ 0.31) in CON vs. ALG cattle; however, plasma Zn concentrations linearly increased ( = 0.03) as ALG increased in the diet. Total lipid, SFA, MUFA, and PUFA concentrations in the longissimus thoracis did not differ ( ≥ 0.13) between CON- and ALG-fed cattle. Interestingly, the atherogenic index linearly decreased ( < 0.01) as ALG increased in the diet. Algae meal may have a lesser energy value than corn; however, a minimal effect on carcass performance suggests ALG may serve as a potential replacement for corn in feedlot diets.

Effect of a multielement trace mineral injection before transit stress on inflammatory response, growth performance, and carcass characteristics of beef steers

Weaned calves (n = 98; 256 ± 11.5 kg) were used to evaluate the impact of improving trace mineral (TM) status using a multielement TM injection 28 d before transit on markers of inflammatory and stress responses in response to transit and postshipping growth performance. On d 0 of a 28-d preconditioning program, calves received subcutaneous TM injection (MM; n = 48) containing 15, 10, 5, and 60 mg/mL of Cu, Mn, Se, and Zn, respectively, or physiological saline injection (SAL; n = 48). On d 28, steers were weighed, half of the steers from each treatment were transported for a 20-h transit stress period (SHIP; n = 24 per injection treatment), and half of the steers were returned to their pens for 20 h of feed and water restriction without transit (NOSHIP; n = 24 per injection treatment). The SHIP steers were unloaded on d 29 and all steers (SHIP and NOSHIP) were immediately weighed and sorted into new pens (n = 4 steers per pen) for the growing period. At the start of finishing (d 113), steers received a second MM or SAL, resulting in a 2 × 2 × 2 factorial (n = 12 steers per treatment combination). Samples of blood were collected on d 28, 29, and 34 and liver on d 22 and 40. The initial MM increased liver Cu, Se, and Zn concentrations of cattle (P ≤ 0.02) but did not affect ADG during preconditioning (P = 0.89) or BW shrink as a result of transit (P ≥ 0.52). Plasma Fe concentrations were decreased after the transit stress period in SHIP calves (P ≤ 0.05) relative to NOSHIP calves but recovered 5 d after transit, and serum IL-8 concentrations were greater in SAL-SHIP steers than MM-SHIP steers (P = 0.04). Altering TM status through MM caused steers to have lesser ADG (P = 0.03) during the 14-d period after transit (d 29 through 43) but did not affect growth during the growing period (d 5 through 112; P ≥ 0.40). Minimal effects on finishing performance and carcass characteristics were noted, but there was a 3-way interaction (P ≤ 0.02) in which SAL-NOSHIP-MM steers had the greatest yield grade (YG) and smallest ribeye area (REA) and SAL-SHIP-MM steers had the least YG and largest REA. Overall, a MM 28 d before transit or before feed and water restriction did not affect the inflammatory response or plasma TM concentrations but decreased ADG in the 14-d period after transit. Trace mineral injection had limited effects on overall growth performance and carcass characteristics, likely because steer initial TM status was well within the adequate range.

Influence of distillers grains resulting from a cellulosic ethanol process utilizing corn kernel fiber on nutrient digestibility of lambs and steer feedlot performance

Two experiments evaluated the effects on animal performance of traditional wet distillers grains (T-WDG) compared to cellulosic wet distillers grains (C-WDG) from a new process converting corn kernel fiber into cellulosic ethanol. The resulting coproduct has greater CP and decreased starch and ether extract (EE) concentrations (34.0% CP, 1.6% starch, 7.3% EE) compared to T-WDG (32.5% CP, 5.1% starch, 7.7% EE). In Exp. 1, 10 wethers (34.1 ± 2.35 kg, SD) were used in a replicated 5 × 5 Latin square to evaluate digestibility of DM, fiber, EE, and N. Diets including a corn-based control with 7.5% T-WDG and 7.5% C-WDG (CORN); 30% or 45% inclusion of T-WDG; and 30% or 45% inclusion of C-WDG. Between CORN, 30% T-WDG, 45% T-WDG, or 45% C-WDG, DMI was not different (P ≥ 0.11), but lambs fed 30% C-WDG had decreased (P ≤ 0.05) DMI compared to other diets. Compared to CORN and 30% T-WDG, DM digestibility was lesser ( P< 0.05) for 45% T-WDG or 30% C-WDG, while 45% C-WDG has lesser (P ≤ 0.05) DM digestibility than all other treatments. Digestibility of NDF was not affected by treatment (P= 0.13), and ADF digestibility was not different ( 0.21) between CORN, 30% T-WDG, 30% C-WDG, or 45% C-WDG. However, digestibility of ADF tended to differ (P = 0.06) between 30% T-WDG and 45% C-WDG and was greater (P ≤ 0.05) in lambs fed 45% T-WDG compared to other treatments. In Exp. 2, 168 steers (421 ± 23.9 kg, SD) were used in a randomized complete block design to determine the impact of C-WDG or T-WDG on growth performance and carcass characteristics. Diets included a corn-based control (CON), 30% T-WDG (TRAD), 30% C-WDG (CEL), and 18% C-WDG and 12% condensed corn distillers solubles (CEL+CCDS; = 7 pens of 6 steers/pen). Steers fed TRAD had improved (P ≤ 0.01) ADG, G:F, and HCW compared to steers fed the CON diet. No differences (P ≥ 0.16) in ADG and HCW were noted for steers fed CEL compared to TRAD; however, steers fed CEL had decreased (P = 0.01) G:F due to increased (P = 0.02) DMI compared to TRAD-fed steers. Steers fed CEL or CEL+CCDS did not differ (P = 0.50) in G:F, but CEL+CCDS-fed steers had lesser (P ≤ 0.01) DMI and ADG likely due to greater S content of the CEL+CCDS diet. Overall, while DM digestibility of lambs fed 30% C-WDG was lesser than 30% T-WDG, performance of steers finished on C-WDG was similar to those fed T-WDG. However, WDG from the secondary fermentation appeared to have lesser energy than T-WDG, while maintaining similar cattle performance to corn-fed controls.

Assessment of algae meal as a ruminant feedstuff: Nutrient digestibility in sheep as a model species

Heterotrophic microalgae combined with soyhulls forms an algae meal (ALG), which contains partially deoiled microalgae (PDM; 57% DM basis) and soyhulls (43%). Two experiments were conducted to evaluate the effects of PDM and ALG on lamb digestibility. In Exp. 1, 8 wethers (23.02 ± 0.54 kg) were used in a 4 × 4 Latin square design to determine the effect of the PDM portion of ALG on total tract nutrient digestibility. Diets included a soyhull-based control (CON; 53% soyhulls), 10% PDM from ALG, 20% PDM from ALG (PDM20), and 30% PDM from ALG. Dry matter and OM intake and fecal DM and OM output were similar ( ≥ 0.11) between CON- and ALG-fed lambs. Urine output linearly increased ( = 0.02) as PDM increased in diets. Dry matter, OM, NDF, and ADF digestibility linearly decreased ( < 0.01) as PDM increased in diets. Ether extract digestibility did not differ ( = 0.24) between CON- and PDM-fed lambs. Nitrogen digestibility and N retention linearly decreased ( ≤ 0.05) as PDM increased in the diet. In Exp. 2, to determine the effects of ALG on diet and nutrient digestibility and N retention, 10 whiteface cross wethers (33.71 ± 0.55 kg) were used in a replicated 5 × 5 Latin square. Diets included a cracked corn-based control (CORN), 15% ALG, 30% ALG, 45% ALG (ALG45), and 60% ALG (ALG60). Dry matter and OM digestibility linearly ( < 0.001) decreased as ALG inclusion increased. Digestibility of NDF and ADF were lesser ( ≤ 0.03) for CORN-fed sheep than for ALG-fed sheep and linearly ( ≤ 0.03) increased as ALG increased in the diet. Ether extract digestibility was lesser ( = 0.002) for CORN than ALG, with a linear ( = 0.002) increase as ALG inclusion increased. There was a cubic ( = 0.03) effect for N digestibility with ALG45 and ALG60 being lesser and CORN being greater than all other treatments. Retention of N and plasma urea N concentration did not differ ( ≥ 0.22) between CORN and ALG. Nonfibrous carbohydrate digestibility linearly ( < 0.001) decreased as ALG increased in the diet. These results suggest that the PDM portion of ALG may be less digestible than soyhulls in ruminants, and differences in N retention in Exp. 1 may suggest an effect on growth in lambs. Furthermore, changes in digestibility of specific nutrients suggest that ALG is more characteristic of a concentrate rather than a fibrous feedstuff. However, lambs will readily consume ALG and this novel feedstuff could potentially serve as a viable component of ruminant diets.

Impact of supplementing vitamin C for 56, 90, or 127 days on growth performance and carcass characteristics of steers fed a 0.31 or 0.59% sulfur diet

The objective was to examine differential timing of vitamin C (VC) supplementation during the finishing period (for the first 56, 90, or 127 d) on performance, VC, and glutathione (GSH) concentrations and carcass traits of steers receiving a 0.31 or 0.59% S diet. Angus steers (n = 42) were stratified to pens by initial BW (304 ± 13 kg) and GeneMax marbling score (4.3 ± 0.12), and pens were randomly assigned to 1 of 7 treatments (6 steers/pen and 1 pen/treatment), including a high-S (HS; 0.59% S) control (HS CON), HS CON + 10 g VC∙steer(-1)∙d(-1) for the first 56 d of the finishing period, HS CON + 10 g VC∙steer(-1)∙d(-1) for the first 90 d of the finishing period, HS CON + 10 g VC∙steer(-1)∙d(-1) for the entire 127-d finishing period (HS VC127), low-S (LS; 0.31% S) diet + 10 g VC∙steer(-1)∙d(-1) for the first 56 d of the finishing period (LS VC56), LS diet + 10 g VC∙steer(-1)∙d(-1) for the first 90 d of the finishing period, or LS diet + 10 g VC∙steer(-1)∙d(-1) for the entire 127-d finishing period. Jugular blood and ultrasound measures were taken from all steers before feeding on d 0, 56, 90, and 127, and liver biopsies and ruminal hydrogen sulfide measurements were collected on d 121 or 122. Steers (n = 40) were harvested on d 127, and carcass data were collected. Data were analyzed by ANOVA as a completely randomized design with the fixed effect of treatment. Because individual intake data were collected, steer was the experimental unit. Final BW and ADG were greater (P ≤ 0.03) and DMI tended (P = 0.09) to be greater in the LS steers compared to HS steers, but G:F did not differ (P = 0.41) by treatment. A treatment × time effect (P = 0.04) for DMI was noted, likely due to lesser DMI between d 91 and 127 for all treatments except the HS VC127 and LS VC56. Plasma VC concentrations of LS steers were less (P = 0.05) than the HS steers. Total (P = 0.06) and reduced (P = 0.03) plasma GSH were greater in HS steers supplemented with VC than the HS CON, but liver GSH were not different due to S or VC (P ≥ 0.13). The ratio of oxidized to reduced liver GSH was greater (P < 0.01) in HS CON than HS steers supplemented with VC. Marbling score, LM area, KPH, and quality grade were not different (P ≥ 0.19) due to diet, but LS steers had greater (P = 0.05) back fat than HS steers. In conclusion, steers fed a HS diet had poorer live performance and unexpectedly greater plasma ascorbate concentrations than the LS-fed steers. Interestingly, increasing days of VC supplementation across the HS diets increased GSH indices, suggesting that although HS diets may negatively affect antioxidant capacity of cattle, supplementing VC may help correct this.

Quantitative relationships between standardized total tract digestible phosphorus and total calcium intakes and their retention and excretion in growing pigs fed corn-soybean meal diets

An experiment was conducted to determine the quantitative relationships between standardized total tract digestible P (STTD P) and total Ca intakes with their retention and excretion by growing pigs fed corn-soybean meal diets. Forty-eight crossbred barrows (BW = 22.7 ± 2.9 kg) were allotted to 1 of 8 diets, housed individually in pens for 3 wk, and then moved to metabolism crates and allowed 4 d for adaptation and 5 d for collection of urine and fecal samples. Eight corn-soybean meal diets were formulated for similar NE, fat, and AA concentrations but to increase the STTD P from 0.16 to 0.62% using monocalcium phosphate. Dietary treatments were formulated for a constant Ca:STTD P ratio (2.2:1). The STTD P intake increased (P < 0.001) from 64 to 242% of the daily requirement (4.59 g/d of STTD P). Fecal and total excretion of P and Ca were linearly associated with mineral intake (P < 0.001). Constant urinary P excretion of 0.03 g/d P was observed, but at 4.96 g/d of STTD P intake, the urinary P excretion increased (P < 0.001). In contrast, Ca excretion in urine decreased (P < 0.001) with Ca intake, but constant excretion of 0.40 g/d Ca was reached at 17.97 g/d of Ca intake. The daily intakes of STTD P and Ca moderately explained the variation in urinary excretion of P (R2= 0.41) and Ca (R2= 0.64). The absorption and retention of P increased linearly (P< 0.001) with dietary P intake, whereas absorption and retention of Ca showed a quadratic response (P < 0.001). Absorption and retention of P and Ca were highly predictable from the STTD P and Ca intakes, with of 0.87 and 0.90, respectively. The femur mineral content (FMC) increased by 2.71 g with STTD P intake (P < 0.001) but reached a plateau (29.54 g of FMC) at 8.84 g/d of STTD P intake. The FMC was highly predictable from the STTD P intake (R2 = 0.89). The FMC affected the urinary P excretion ( P< 0.01), but moderately (R2= 0.19) explained the variation in urinary P. In conclusion, constant excretion of P in urine was observed but excretion increased linearly at STTD P intake levels above the requirement for maximum growth of growing pigs. The FMC increased with STTD P intake, but a plateau was reached at a STTD P intake level above the requirement. Dietary STTD P was used for growth and accumulated in bones until a plateau was reached and excess was excreted in urine. The predictability of P and Ca excretion in urine from the dietary STTD P and Ca intakes was moderate.

The effect of trace mineral source and concentration on ruminal digestion and mineral solubility

The objective of this experiment was to compare the effect of sources of sulfate trace mineral (STM) and hydroxy trace mineral (HTM) at different inclusions on digestibility of dry matter (DM) and neutral detergent fiber and solubility of Cu, Mn, and Zn in the rumen and abomasum of cattle. Five ruminally cannulated steers were used in a 5×5 Latin square design and individually fed a corn silage-based diet on an ad libitum basis. The 5 dietary treatments were as follows: control: no supplemental Cu, Mn, or Zn, analyzed to contain 7.4mg of Cu, 30.8mg of Mn, and 32.1mg of Zn per kilogram of diet DM (CON); low sulfate: 5mg of Cu/kg of DM supplemented from CuSO4, 15mg of Mn/kg of DM from MnSO4, and 30mg of Zn/kg of DM from ZnSO4; low HTM: 5mg of Cu/kg of DM supplemented from basic copper chloride (IntelliBond C; Micronutrients Inc., Indianapolis, IN), 15mg of Mn/kg of DM from manganese hydroxychloride (IntelliBond M; Micronutrients Inc.), and 30mg of Zn/kg of DM from zinc hydroxychloride (IntelliBond Z; Micronutrients Inc.); high sulfate: 25mg of Cu/kg of DM supplemented from CuSO4, 60mg of Mn/kg of DM from MnSO4, and 120mg of Zn/kg of DM from ZnSO4; and high HTM: 25mg of Cu/kg of DM supplemented from basic copper chloride, 60mg of Mn/kg of DM from manganese hydroxychloride, and 120mg of Zn/kg of DM from zinc hydroxychloride. Periods lasted for 12d, with 10d of diet adaptation. Dacron bags containing the CON total mixed ration were inserted on d 11 at 0h and were removed at 6, 12, 24, and 36h after insertion. Dry matter and neutral detergent fiber disappearances and rumen and simulated abomasal trace mineral solubilities were evaluated. Dietary treatment did not affect DM intake. Dry matter disappearance was lesser in supplemental TM treatments and greater in CON than the STM treatments, although the CON and HTM treatments did not differ. Neutral detergent fiber disappearance was not affected by treatment. Ruminally soluble Cu and Mn concentrations were least in CON and were lesser in HTM-containing treatments compared with STM treatments. However, in the abomasum, solubilities of Cu and Mn were similar across trace mineral sources. Ruminal and simulated abomasal soluble Zn was greater in the HTM treatments than in CON and STM, driven by the greater solubility of the high HTM treatment. Under the conditions of this study, supplementing trace minerals as STM decreased DM digestibility, whereas HTM did not affect DM digestibility. Additionally, Cu and Mn from HTM sources were relatively insoluble in the rumen but had similar solubility as STM at the pH found in the abomasum, suggesting that these minerals should be available for absorption in the intestine.

Increasing dietary neutral detergent fiber concentration decreases ruminal hydrogen sulfide concentrations in steers fed high-sulfur diets based on ethanol coproducts

Cattle feedlot diets commonly contain ethanol coproducts that are high in S. This dietary S is reduced in the rumen by sulfate reducing bacteria, resulting in an accumulation of hydrogen sulfide (H2S), increasing the risk for S toxicity. A negative correlation between H2S and ruminal pH has been observed previously. The objective of this study was to determine the effect of varying dietary NDF from chopped bromegrass hay (66% NDF) on performance, ruminal pH, and ruminal H2S gas concentration of steers fed a high-S finishing diet. One hundred fifty crossbred steers (359 ± 51 kg BW) were blocked by BW into pens of 5 steers and randomly assigned within block to 1 of 5 treatments (n = 6 pens per treatment) and fed for 84 d. Dietary treatments included 3.5, 5.7, 7.9, 10.1, or 11.4% roughage NDF (rNDF) from bromegrass hay and contained 0.46% dietary S from a combination of dried distillers grains with solubles and condensed corn distillers solubles. In all diets, hay was added at the expense of dry-rolled corn. Effective NDF increased linearly (P < 0.01) with increased inclusion of rNDF. Final BW was not affected by rNDF (P ≥ 0.12). The addition of roughage did not affect ADG (P ≥ 0.13) or gain efficiency (P ≥ 0.12). Dry matter intake increased linearly (P < 0.01) as rNDF concentration increased. There was a treatment × month interaction for S intake (P < 0.01), explained by steers fed 3.5 or 11.4% rNDF increasing S intake each month whereas the middle rNDF inclusions had similar S intake between months 1 and 2 and increased in month 3. Ruminal H2S concentrations and ruminal fluid pH were measured at 6 h postfeeding on d 7, 14, 21, 29, and 84. Ruminal pH increased linearly (P < 0.01; 5.48, 5.61, 5.71, 5.74, and 5.80 ± 0.041 for 3.5, 5.7, 7.9, 10.1, and 11.4% rNDF, respectively) and ruminal H2S concentrations decreased linearly (P < 0.01; 1.00, 0.86, 0.76, 0.70, and 0.62 ± 0.037 g/m(3) for 3.5, 5.7, 7.9, 10.1, and 11.4% rNDF, respectively) as rNDF inclusion increased. Using mixed model regression analysis, ruminal pH had a strong negative relationship with ruminal H2S concentrations (β = -0.63; P < 0.01). Under conditions of this study, increasing roughage did not affect cattle gains but helped maintain greater ruminal pH and decreased H2S concentration, suggesting that this dietary strategy may lessen the risk of S toxicity in feedlot cattle.

High dietary sulfur decreases the retention of copper, manganese, and zinc in steers

To examine the effects of dietary S on diet digestibility and apparent mineral absorption and retention, 16 steers [8 ruminally fistulated (368 ± 12 kg BW) and 8 unmodified (388 ± 10 kg BW)] were paired within modification status and BW, and within each of the 2 consecutive 28-d periods, 4 pairs of steers were randomly assigned to either a low-S (0.24%) or high-S (0.68%) pelleted diet. Bromegrass hay was fed at 5 or 7% of the diet, during periods 1 and 2, respectively. Sodium sulfate was used to increase the S content of the high-S diet. The low-S steers were fed the amount of feed their high-S counterpart consumed the previous day, while the high-S steers received 110% of the previous day's intake. Steers were adapted to individual metabolism stalls for 4 d (d -3 to 0 of period), acclimated to diet for 7 d (d 1 to 7 of period), and after high-S steers were consuming ad libitum intake for 7 d (d 14 of period), total urine and feces were collected for 5 d. Feed intake and orts were recorded daily. Dry matter and OM digestibility were determined. Jugular blood was collected before and after each collection period on d 14 and 20, and liver biopsies were collected on d 0 and 27. Macromineral (Ca, K, Mg, and Na) and micromineral (Cu, Mn, and Zn) concentrations were determined for pellets and hay, orts, feces, urine, and plasma and liver samples from each steer via inductively coupled plasma spectrometry. Dry matter intake, DM and OM digestibility, and urine volume were not affected (P ≥ 0.11) by dietary treatment, but fecal output was greater (P = 0.02) in the low-S steers than the high-S steers. A high-S diet decreased plasma Cu (P = 0.04) and liver Zn (P = 0.03) compared to low-S steers. No differences (P ≥ 0.20) were noted among urinary excretion of Cu, Mn, and Zn. Sodium absorption was greater (P < 0.01) and Cu, Mn, and Zn retention was lesser (P ≤ 0.01) in the high-S steers than the low-S steers. Apparent absorption of Ca, K, and Mg was not affected (P ≥ 0.18) by dietary treatment, while absorption of Cu, Mn, and Zn in the high-S treatment was lesser (P ≤ 0.06). In conclusion, consumption of a high-S diet for 28 d had limited effects on Ca, K, Mg, and Na absorption and retention, but decreased Cu, Mn, and Zn retention, which may limit growth and production of cattle consuming a high-S diet long-term.

Determining the influence of dietary roughage concentration and source on ruminal parameters related to sulfur toxicity

Cattle feedlot diets often include ethanol coproducts that provide excess dietary sulfate, which is reduced to sulfide by ruminal bacteria and can be converted to hydrogen sulfide, which has been correlated to S toxicity. The objective of this study was to determine the impact of feeding varying concentrations of NDF from chopped cornstalks (CS) or chopped bromegrass hay (BH) on ruminal pH, ruminal H2S concentration, and DMI of steers fed a high-S finishing diet. Five ruminally fistulated steers (595 ± 87 kg BW) were used in a 6 × 6 Latin square with 14-d periods and fed diets containing 0.45% S from a mixture of dried distillers grains and condensed corn distillers solubles. The study was a 2 × 3 factorial arrangement of treatments with 2 roughage sources--CS or BH--and 3 concentrations of added roughage NDF (rNDF)--4, 7, or 10%. Steers had individual ad libitum access to feed and adapted to each diet for the first 7 d of each period. Effective NDF linearly increased (P < 0.01) as rNDF increased and did not differ between sources (P = 0.44). There was no effect of concentration or source of rNDF on DMI (P ≥ 0.69). Steer behavior was observed on d 13 of each period for 3 h postfeeding. Source of rNDF did not affect time at bunk, DMI during observation, or rate of DMI (P ≥ 0.42). Time at bunk linearly increased as rNDF increased (P = 0.01), while rate of DMI linearly decreased (P = 0.02). Area under the curve for ruminal pH of 5.4, 5.6, and 5.8, calculated using data from d 8 to 14 via an indwelling ruminal bolus, were linearly decreased (P ≤ 0.03) as rNDF increased. Manual ruminal pH taken 6 h postfeeding on d 14 of each period did not differ by source (P = 0.12) but linearly increased (P < 0.01) as rNDF increased. Ruminal H2S concentrations measured 6 h postfeeding on d 14 of each period did not differ by source (P = 0.47) but linearly decreased (P < 0.01) as rNDF increased (0.62, 0.35, 0.31 g/m(3) for 4, 7, and 10% rNDF, respectively). A segmented linear model was found to best fit the ruminal pH and H2S relationship data, suggesting that at or below a pH of 5.6 ± 0.08 with 95% confidence intervals of 5.4 and 5.8, pH is a strong predictor of H2S (P ≤ 0.05), while above this pH range H2S concentrations are not well correlated with ruminal pH (P > 0.50). In conclusion, adding at least 7% NDF from CS or BH to high-S feedlot cattle diets will increase ruminal pH and decrease H2S concentrations, thus decreasing potential for S toxicity.

Effect of varying concentrations of vitamin C on performance, blood metabolites, and carcass characteristics of steers consuming a common high-sulfur (0.55% S) diet

The objective of this study was to examine the effects of vitamin C (VC) supplementation for an average of 102 d before harvest on finishing performance and blood metabolites of steers receiving a 40% dry distillers grains plus solubles diet (0.55% S). Yearling, Angus-cross steers (n = 140) were blocked by initial BW (432 ± 25.5 kg), stratified within blocks by intramuscular fat (3.6% ± 0.30%) determined by ultrasonography, and assigned to treatments (5 steers/pen, 7 pens/treatment). Treatments included 1) no VC control (CON), 2) 5 g VC • steer(-1) • d(-1) (5VC), 3) 10 g VC • steer(-1) • d(-1) (10VC), and 4) 20 g VC • steer(-1) • d(-1) (20VC). Jugular blood was collected from 2 steers/pen before feeding at the beginning and end of the 102-d study, and steers were harvested by block on 3 separate dates (d 91, 105, and 112). Sulfur intake linearly decreased (P = 0.01) as VC inclusion increased (59.2, 57.7, 57.0, and 54.8 ± 0.79 g S • steer(-1) • d(-1) for CON, 5 VC, 10 VC, and 20 VC, respectively). The CON cattle had greater (P < 0.01) DMI than the VC-supplemented cattle. Inclusion of VC did not influence ADG or final BW, resulting in a tendency for a linear increase (P = 0.08) in G:F as VC inclusion increased (0.150, 0.152, 0.158, and 0.160 ± 0.004 for CON, 5 VC, 10 VC, and 20 VC, respectively). Ending (2 d before harvest) plasma ascorbate showed a quadratic effect (P < 0.05) because of lesser concentrations exhibited by 5 VC cattle (1,186 µg/L) compared with the CON (1,454 µg/L), 10 VC (1,304 µg/L), and 20 VC (1,436 µg/L; SEM ± 64.8) cattle. Ending plasma insulin concentrations of CON cattle tended (P = 0.07) to be less than the VC-supplemented cattle. Plasma glucose and NEFA concentrations were not affected (P ≥ 0.23) by VC inclusion. Hot carcass weight, 12th-rib back fat, marbling, and quality grade were not affected (P ≥ 0.27) by VC inclusion. Increasing VC inclusion linearly increased (P = 0.02) rib eye area (84.9, 86.5, 88.7, and 89.1 cm(2) ± 1.17 for CON, 5 VC, 10 VC, and 20 VC, respectively), corresponding to a linear decrease (P = 0.02) in yield grade with increasing inclusions of VC. A tendency (P = 0.06) for a quadratic effect on KPH was observed, in which values generally increased from CON (2.27%) to 5 VC (2.37%) to and 10 VC (2.39%), then decreased in 20 VC (2.20%). In conclusion, VC supplementation to a high-S diet for an average of 102 d before harvest has limited effects on blood metabolites but increased rib eye area and tended to increase feed efficiency of yearling steers.

Supplemental vitamin C improves marbling in feedlot cattle consuming high sulfur diets

The objective of this study was to examine the effects of supplemental rumen-protected vitamin C (VC) on live and carcass-based performance, and antioxidant capacity of cattle consuming varying concentrations of dietary S. Angus-cross steers (n = 120) were blocked by initial BW (341 ± 11 kg) and assigned equally to 1 of 6 treatments, evaluating 3 concentrations of dietary S [0.22%, 0.34%, and 0.55%, for low S (LS), medium S (MS), and high S (HS), respectively] and 2 concentrations of supplemental VC (0 or 10 g • steer(-1) • d(-1)). Steers receiving VC-supplemented diets consumed an average of 10.3 g of supplemental VC • steer(-1) • d(-1) and increasing dietary S linearly increased (P < 0.01) grams of S consumed. Increasing dietary S decreased (P < 0.01) DMI, final BW, and ADG, and linearly increased (P < 0.05) rumen hydrogen sulfide and blood sulfhemoglobin concentrations. The inclusion of VC, regardless of S treatment, tended to increase (P = 0.08) plasma VC concentrations, specifically within the medium and high S diets (P = 0.04). Plasma total antioxidant capacity (d 90) linearly decreased (P = 0.003) and total liver glutathione (GSH; d 143) tended to decrease (P = 0.08) due to increased S intake. Within the high S treatment, addition of VC decreased (P = 0.04) the ratio of oxidized-to-reduced GSH compared with HS alone. Increased dietary S and VC decreased (P < 0.05) plasma Cu concentrations, whereas VC increased (P = 0.01) plasma Fe concentrations. Linear decreases (P < 0.02) in marbling score, backfat thickness (BF), yield grade, and HCW were observed as dietary S increased; however, the addition of VC to the HS diet increased (P < 0.01) BF, marbling scores, and percentage of cattle grading Choice compared with HS without VC. In conclusion, supplementation of VC to cattle receiving the high S diet improved marbling scores; although the exact mechanism for this improvement is unknown, it may be related to greater circulating VC available for lipid metabolism in these cattle.

Mineral concentrations of plasma and liver after injection with a trace mineral complex differ among Angus and Simmental cattle

To examine the effects of cattle breed on the clearance rate of an injectable mineral product, 10 Angus and 10 Simmental steers were blocked by breed and initial BW (332 ± 33 kg) and injected with either Multimin 90 (MM) or sterilized saline (CON) at a dose of 1 mL/45 kg BW. Multimin 90 contains 15 mg Cu/mL (as Cu disodium EDTA), 60 mg Zn/mL (as Zn disodium EDTA), 10 mg Mn/mL (as Mn disodium EDTA), and 5 mg Se/mL (as sodium selenite). Steers received a corn-silage-based diet, and inorganic sources of Cu, Zn, Mn, and Se were supplemented at NRC recommended amounts. Jugular blood was collected immediately before injection and at 8 and 10 h post-injection and on days 1, 8, and 15 post-injection. Liver biopsies were collected 3 d before injection and on days 1, 8, and 15 post-injection. Liver and plasma mineral concentration and glutathione peroxidase (GSH-Px) activity data were analyzed as repeated measures. Plasma concentrations of Zn, Mn, and Se were greater (P = 0.01) and Cu tended to be greater (P = 0.12) post-injection in MM steers compared with the CON steers. Regardless of treatment, Simmental cattle had lower plasma concentrations of Cu, Zn, and Se (P ≤ 0.05) when compared with Angus cattle. Erythrocyte GSH-Px activity was greater (P = 0.01) in MM steers compared with CON steers. Liver concentrations of Cu, Zn, and Se were greater (P = 0.05) in MM steers compared with CON steers post-injection. Liver Mn concentrations tended to be greater (P = 0.06) in MM steers compared with CON steers in the days post-injection. Interestingly, Simmental cattle exhibited greater (P = 0.01) liver Mn concentrations in the days after injection compared with Angus cattle (7.0 and 6.0 mg Mn/kg for Simmental and Angus cattle, respectively), regardless of treatment. It is unclear if this breed difference is biologically relevant; however, these data may suggest that differences in liver excretion of Mn exist between the two breeds. Overall, use of an injectable trace mineral increased liver concentrations of Cu and Se through the 15-d sampling period, suggesting that this injectable mineral is an adequate way to improve Cu and Se status of cattle through at least 15 d.

Dietary sulfur concentration affects rumen hydrogen sulfide concentrations in feedlot steers during transition and finishing

Angus steers (n = 96; 321 ± 29 kg BW) were used to determine how previous exposure to increased dietary S would affect ruminal hydrogen sulfide concentrations ([H(2)S]) in the feedlot, to investigate the effects of dietary S on ruminal [H(2)S] during transition and finishing, and to determine if dietary S affects the glutathione status of finishing cattle. Steers were strip-grazed on smooth bromegrass (Bromus inermis L.) over a 35 d period and received a dry distillers grains plus solubles (DDGS) supplement at 1% of BW (DM basis) that contained either 0.50% S (LS; n = 4 plots) or the DDGS supplement with an additional 0.30% S from sodium sulfate (0.80% S in supplement; HS; n = 4 plots). On d 36 steers were moved from the pastures to feedlot pens with one-half of the steers on each treatment in the pasture period remaining on the same treatment during the feedlot period and half being switched to the other treatment (n = 6 pens). For the first 10 d in the feedlot, steers were fed hay ad libitum and 1% BW of the DDGS supplement representing their new treatment, followed by transition to finishing diets. Dietary S of transition and finishing diets were 0.2% to 0.3% S for LS and 0.5% to 0.6% S for HS. No interaction between pasture and feedlot treatment was observed (P ≥ 0.50), so data for the feedlot period were pooled by feedlot treatment (n = 12 pens). Rumen [H(2)S] were measured on d 35 of the pasture period and on d 46 while receiving ad libitum hay and supplement at 6 h after the feeding of the supplement and after 7 d on each of the 3 transition diets (d 53, 60, and 67) and on d 93, 126, and 155 of the study after receiving the finishing diet for 26, 59, and 88 d at 6 h after feeding. Ruminal [H(2)S] did not differ between treatment while steers were fed the supplement on forage-based diets. However, ruminal [H(2)S] of HS-fed steers was greater (P < 0.05) than LS-fed steers when transition diets and the finishing diets were fed. Relative to S intake, ruminal [H(2)S] increased disproportionally after 26 d on the finishing diet. This was followed by a decrease in [H(2)S] on d 59 of finishing, although S intake was increased (P < 0.05) compared with d 26 of finishing. It appears that factors other than S intake alone contribute to ruminal [H(2)S]. The amount of glutathione in the liver of steers did not differ (P = 0.47) because of dietary S, but the concentration of oxidized glutathione increased (P = 0.03) in HS-fed compared with LS-fed steers, suggesting that the potential for oxidative stress in cattle fed high-S diets may warrant further investigation.

Reconstruction of an entire metacarpal and metacarpophalangeal joint using a fibular osteocutaneous free flap and silicone arthroplasty

Radical resection of the entire ring finger metacarpal for a giant cell tumor resulted in a bony defect extending from the distal surface of the hamate to the proximal surface of the proximal phalanx. We reconstructed the metacarpal with a custom-contoured free fibular osteocutaneous flap and maintained motion at the new fibulophalangeal joint using a silicone arthroplasty. At 4.5 years postoperatively, the patient has shown no signs of recurrence of the giant cell tumor. The silicone arthroplasty has maintained 15° to 85° of motion at the new joint. Because of its similar shape to a metacarpal and because it allows faster bony healing compared with a nonvascularized fibular bone graft, a free vascularized fibular bone graft is an ideal candidate for reconstruction of extensive defects of the metacarpals, and placement of a silicone spacer in its distal medullary cavity can preserve motion at the new metacarpophalangeal joint.

Single-stage reconstruction of a devastating antebrachial injury with brachial artery, median nerve, and soft tissue deficit: a case report and review of the literature

OBJECTIVE

We present a case of a 31-year-old man who fell through a skylight sustaining a deep laceration injury to his dominant arm. A single-stage radial artery flow-through free flap and cabled sural nerve graft for reconstruction of a complex antebrachial defect involving skin, soft tissue, muscle, brachial artery, and median nerve was performed. A technical description of the case and review of the literature are described.

METHODS

Traumatic injuries to the arm and antecubital fossa often lead to devastating outcomes. Advances in microsurgical technique as well as improved skin and dermal substitutes have allowed improved outcomes as well as shorter hospital stays. In this case, surgical treatment involved microsurgical reconstruction of the brachial artery with a radial artery flow-through flap and a single-stage donor-site closure with an Integra dermal matrix template and split-thickness skin graft.

RESULTS

Successful vascular flow and soft tissue coverage were performed with successful salvage of the limb.

CONCLUSION

A single-stage reconstruction versus a multistage, delayed reconstruction of a devastating arm injury with a radial forearm flow-through flap and single-stage closure with Integra and autologous skin graft can provide a safe, effective, and clinically satisfactory outcome.

Surgical treatment options for subacute ischemia of the hand: case report and literature review

PURPOSE

The most effective surgical approach to the treatment of digital ischemia has not yet been established. The purpose of this study is to review currently accepted options for revascularization in acute and chronic settings of digital ischemia, and to augment this discussion by describing the approach of our surgical team in a unique case of subacute ischemia.

OPERATIVE TECHNIQUE

To restore blood flow to a patient's ischemic hand, we performed a microvascular reconstruction, using a reverse interpositional vein graft with 3 anastomoses: the ulnar artery was used for inflow and the superficial palmar arch and the common digital artery were used for outflow.

RESULTS

The patient experienced immediate postoperative pain relief. Blood flow was restored, which prevented digital amputation. The graft remained patent at 18 months' follow-up and the patient exhibited normal motor and sensory function.

CONCLUSIONS

Surgical reconstruction of the hand is a viable treatment option for carefully selected patients presenting with subacute digital ischemia. Other medical and surgical techniques have been described in the recent literature, but further study is needed to determine the long-term success of newer microsurgical interventions.