Effects of rubber matting on feedlot cattle growth performance, locomotion, and carcass characteristics in slatted floor facilities.

The objective was to determine effects of old and new rubber matting in a slatted, indoor cattle feeding facility on cattle growth performance, locomotion, and carcass characteristics. In experiment 1, fall-born Angus × Simmental steers (N = 207; body weight = 222 ± 38 kg) were blocked by weight and assigned to 32 pens. Pens were randomly assigned to 1 of 4 treatments: no matting/concrete (CONC1), 12-yr-old Animat Pebble matting (OLD1), new Animat Maxgrip matting (MG), and new Animat Pebble matting (PEB1). Steers were fed a common diet for 209 d with a minimum stocking density of 3.40 m2 per animal. Final body weight (BW) and average daily gain (ADG) were affected (P = 0.02 and P < 0.01, respectively) by treatment with steers on PEB1 finishing heaviest with the greatest growth, MG and CONC1 intermediate, and OLD1 finishing at the lightest final BW with the least growth. Flooring treatment did not affect overall dry matter intake (DMI; P = 0.16) or gain to feed ratio (G:F; P = 0.94). Flooring treatment did not affect (P ≥ 0.19) any carcass traits. Locomotion scores (LS) were affected (P < 0.01) by flooring treatment with CONC1 having the worst mobility while OLD1, MG, and PEB1 were similar (P ≥ 0.24). Locomotion score had a day effect (P < 0.01) where cattle gait and mobility worsened as days on feed increased. In experiment 2, fall-born Angus × Simmental steers (N = 189; BW = 352 ± 43 kg) were blocked by weight and assigned to 21 pens. Pens were randomly assigned to 1 of 3 treatments: no matting/concrete (CONC2), 15-yr-old Animat Pebble matting (OLD2), and new Animat Pebble matting (PEB2). Steers were fed a common diet for 152 d with a stocking density of 2.65 m2 per steer. After 152 d on feed, flooring treatment did not affect (P ≥ 0.30) BW, ADG, or DMI nor did treatment affect (P ≥ 0.17) carcass traits. However, steers housed on OLD2 or PEB2 had improved locomotion scores (P = 0.02) compared with steers housed on CONC2. Locomotion score had a day effect (P < 0.01) as cattle gait and mobility worsened with greater number of days on feed, regardless of treatment. Overall, results suggest that new rubber matting increased ADG and HCW during a 209-d trial when cattle were stocked at 3.4 m2 in small pens and that rubber matting regardless of age improved cattle locomotion scores in slatted indoor feeding facilities.

Many feedlots in the Midwest have constructed slatted indoor cattle feeding facilities to improve winter pen conditions and decrease land requirements. Finishing cattle in indoor feeding facilities can increase cattle growth and carcass value, but greater prevalence of cattle lameness is a concern. Rubber matting is commonly used in these facilities, but it is a consumable product with a variable lifespan. This study evaluated the effects of old and new rubber matting in a slatted, indoor cattle feeding facility on cattle growth performance, locomotion, and carcass characteristics in two experiments. In experiment 1, steers in pens with new Animat Pebble matting had increased growth compared with steers in pens with no matting and 12-yr-old Animal Pebble matting. Furthermore, steers in pens with no matting had the poorest locomotion scores. In experiment 2, flooring treatments did not affect cattle growth or carcass traits, but steers in pens with old or new rubber matting had more desirable locomotion scores than cattle in pens with no matting. Therefore, new rubber matting can improve cattle growth in small pens with slatted floors when cattle were stocked at 3.4 m2 per steer (experiment 1) and that rubber matting regardless of age improved cattle locomotion.

Influence of Rearing Environment on Longitudinal Brain Development, Object Recognition Memory, and Exploratory Behaviors in the Domestic Pig (Sus scrofa).

INTRODUCTION: Over the last 40 years, the domestic pig has emerged as a prominent preclinical model as this species shares similarities with humans with regard to immunity, gastrointestinal physiology, and neurodevelopment. Artificial rearing of pigs provides a number of advantages over conventional rearing (i.e., true maternal care), including careful control of nutrient intake and environment conditions. Yet there remains a gap in knowledge when comparing brain development between sow-reared and artificially reared domestic pigs. Thus, our research sought to model brain development and assess recognition memory in a longitudinal manner by directly comparing rearing environments. METHODS: Forty-four intact (i.e., not castrated) male pigs were artificially reared or sow-reared from postnatal day 2 until postnatal week 4. After postnatal week 4, all pigs were housed in a group setting within the same environment until postnatal week 24. Magnetic resonance imaging was conducted on pigs at 8 longitudinal time-points to model developmental trajectories of brain macrostructural and microstructural outcomes. Additionally, pigs behavior were tested using the novel object recognition task at postnatal weeks 4 and 8. RESULTS: Throughout the 24-week study, no differences between rearing groups were noted in weekly body weights, average growth and feed intake patterns, or feed efficiency. Whole brain, gray matter, white matter, and cerebrospinal fluid growth patterns also did not differ between pigs assigned to different early-life rearing environments. Moreover, minimal differences in regional absolute volumes and fractional anisotropy developmental trajectories were identified, though artificially reared pigs exhibited higher initial rates of myelination in multiple brain regions compared with sow-reared pigs. Furthermore, behavioral assessment at both PNW 4 and 8 suggested little influence of rearing environment on recognition memory, however, an age-dependent increase in object recognition memory was observed in the sow-reared group. CONCLUSION: Our findings suggest that early-life rearing environment influences the rate of development in some brain regions but has little influence on overall brain growth and object recognition memory and exploratory behaviors in the domestic pig. Artificial rearing may promote maturation in certain brain areas but does not appear to elicit long-term effects in outcomes including brain structure or object recognition memory.

Influence of Dietary Polar Lipid Supplementation on Memory and Longitudinal Brain Development.

Polar lipids, which are found in human milk, serve essential functions within biological membranes, hence their importance in brain development and cognition. Therefore, we aimed to evaluate the longitudinal effects on brain macrostructural and microstructural development and recognition memory of early-life polar lipid supplementation using the translational pig model. Twenty-eight intact (i.e., not castrated) male pigs were provided either a control diet (n = 14) or the control diet supplemented with polar lipids (n = 14) from postnatal day 2 until postnatal week 4. After postnatal week 4, all animals were provided the same nutritionally-adequate diets until postnatal week 24. Pigs underwent magnetic resonance imaging at 8 longitudinal time-points to model brain macrostructural and microstructural developmental trajectories. The novel object recognition task was implemented at postnatal weeks 4 and 8 to evaluate recognition memory. Subtle differences were observed between groups in hippocampal absolute brain volumes and fractional anisotropy, and no differences in myelin water fraction developmental patterns were noted. Behavioral outcomes did not differ in recognition memory, and only minimal differences were observed in exploratory behaviors. Our findings suggest that early-life dietary supplementation of polar lipids has limited effect on brain developmental patterns, object recognition memory, and exploratory behaviors.

Emergency ventilator for COVID-19.

The COVID-19 pandemic disrupted the world in 2020 by spreading at unprecedented rates and causing tens of thousands of fatalities within a few months. The number of deaths dramatically increased in regions where the number of patients in need of hospital care exceeded the availability of care. Many COVID-19 patients experience Acute Respiratory Distress Syndrome (ARDS), a condition that can be treated with mechanical ventilation. In response to the need for mechanical ventilators, designed and tested an emergency ventilator (EV) that can control a patient's peak inspiratory pressure (PIP) and breathing rate, while keeping a positive end expiratory pressure (PEEP). This article describes the rapid design, prototyping, and testing of the EV. The development process was enabled by rapid design iterations using additive manufacturing (AM). In the initial design phase, iterations between design, AM, and testing enabled a working prototype within one week. The designs of the 16 different components of the ventilator were locked by additively manufacturing and testing a total of 283 parts having parametrically varied dimensions. In the second stage, AM was used to produce 75 functional prototypes to support engineering evaluation and animal testing. The devices were tested over more than two million cycles. We also developed an electronic monitoring system and with automatic alarm to provide for safe operation, along with training materials and user guides. The final designs are available online under a free license. The designs have been transferred to more than 70 organizations in 15 countries. This project demonstrates the potential for ultra-fast product design, engineering, and testing of medical devices needed for COVID-19 emergency response.

Health Service Impact from Mass Gatherings: A Systematic Literature Review.

BACKGROUND: During a mass gathering, some participants may receive health care for injuries or illnesses that occur during the event. In-event first responders provide initial assessment and management at the event. However, when further definitive care is required, municipal ambulance services provide additional assessment, treatment, and transport of participants to acute care settings, such as hospitals. The impact on both ambulance services and hospitals from mass-gathering events is the focus of this literature review. Aim This literature review aimed to develop an understanding of the impact of mass gatherings on local health services, specifically pertaining to in-event and external health services. METHOD: This research used a systematic literature review methodology. Electronic databases were searched to find articles related to the aim of the review. Articles focused on mass-gathering health, provision of in-event health services, ambulance service transportation, and hospital utilization. RESULTS: Twenty-four studies were identified for inclusion in this review. These studies were all case-study-based and retrospective in design. The majority of studies (n=23) provided details of in-event first responder services. There was variation noted in reporting of the number and type of in-event health professional services at mass gatherings. All articles reported that patients were transported to hospital by the ambulance service. Only nine articles reported on patients presenting to hospital. However, details pertaining to the impact on ambulance and hospital services were not reported. CONCLUSIONS: There is minimal research focusing on the impact of mass gatherings on in-event and external health services, such as ambulance services and hospitals. A recommendation for future mass-gathering research and evaluation is to link patient-level data from in-event mass gatherings to external health services. This type of study design would provide information regarding the impact on health services from a mass gathering to more accurately inform future health planning for mass gatherings across the health care continuum. Ranse J , Hutton A , Keene T , Lenson S , Luther M , Bost N , Johnston ANB , Crilly J , Cannon M , Jones N , Hayes C , Burke B . Health service impact from mass gatherings: a systematic literature review. Prehosp Disaster Med. 2017;32(1):71-77.

Cardiopulmonary exercise test in patients with subacute pulmonary emboli.

OBJECTIVE: Patients presenting with suspected pulmonary embolism (PE) may present a challenge, particularly if diagnostic testing is not immediately available or clinically not indicated (iodine allergy, pregnancy, renal dysfunction). These patients have abnormal regional gas exchange that can be recognized by a cardiopulmonary exercise test (CPET), which may become helpful in their evaluation. METHODS: A retrospective analysis was performed of outpatients evaluated for subacute exertional dyspnea of 2 to 12 weeks duration with a test for PE and CPET. A total of 108 patients met inclusion criteria. Thirty patients (27.8%) had confirmed PE. RESULTS: The patients with PE had increased nadir ventilatory equivalent ratio for carbon dioxide (VE/VCO(2)), decreased peak oxygen uptake/predicted, and decreased end exercise saturation (P < .005 for all). All patients but 1 had normal breathing reserve (>15%). A normal nadir VE/VCO(2) excluded PE with 100% sensitivity. By using a "flow chart strategy," the exercise test had 92.8% sensitivity and 92.1% specificity for PE. Eight patients with PE died during follow-up (3.8 ± 4.6 years), 6 of PE-related causes. Peak VO(2)/kg was the best predictor of all-cause mortality and nadir VE/VCO(2) for PE-related mortality. There were no serious complications from any of the exercise tests. CONCLUSION: PE may be excluded by a normal nadir VE/VCO(2) in patients presenting with subacute dyspnea. A combination of decreased peak VO(2)/kg, increased nadir VE/VCO(2), normal breathing reserve, and exercise-induced desaturation may be sensitive and specific for PE. CPET may assist in identifying subacute PE in patients with contraindications to use of computed tomography angiography or ventilation perfusion scans.

Prognostic utility of metabolic exercise testing in minimally symptomatic patients with obstructive hypertrophic cardiomyopathy.

Patients with obstructive hypertrophic cardiomyopathy (HC) are at increased risk of death or severe symptoms. Although metabolic exercise testing is routinely used in the evaluation of a variety of cardiac diseases, data on the prognostic information that can be derived from such testing in HC is lacking. We examined 182 patients (mean age 53 ± 15 years; 65% men) with obstructive HC and minimal or no cardiovascular symptoms. Each patient underwent maximum exercise testing with simultaneous metabolic gas exchange measurement. Follow-up (mean 4.0 ± 3.0 years; 100% complete) was performed to determine the vital status and occurrence of severe symptoms, defined as class III or IV symptoms of dyspnea or angina. Multiple parameters of metabolic exercise were associated with a risk of death and the development of severe symptoms. On multivariate analyses, the independent predictors of death and severe symptoms were the severity of the left ventricular outflow tract gradient at rest and the percentage of predicted peak myocardial oxygen consumption achieved during exercise. For patients with a percentage of predicted peak myocardial oxygen consumption of <60%, the 4-year survival rate free of death and severe symptoms was only 59%. In conclusion, among patients with obstructive HC and mild or no symptoms, a low metabolic exercise capacity is associated with an increased risk of death and the subsequent development of severe symptoms.

Safety of symptom-limited cardiopulmonary exercise testing in patients with aortic stenosis.

BACKGROUND: There are no published data on the safety of cardiopulmonary exercise testing in patients with aortic stenosis. METHODS: In this retrospective descriptive study, we examined 347 consecutive patients with aortic stenosis who underwent cardiopulmonary exercise testing at a tertiary referral center. We recorded major events including death, nonfatal major events (cardiac arrest, symptomatic or sustained ventricular or supraventricular tachycardia, myocardial infarction, and syncope), and minor events such as hypotension, nonsustained supraventricular and ventricular arrhythmias, positive electrocardiographic changes, and angina. RESULTS: Of 347 patients, 65 (19%) had mild, 145 (42%) had moderate, and 137 (40%) had severe aortic stenosis by echocardiographic criteria. No major events occurred during the tests. Minor events occurred in a total of 97 patients (28%), including 10 patients who developed supraventricular arrhythmias without hypotension; and one who had asymptomatic nonsustained ventricular tachycardia. CONCLUSION: Symptom-limited cardiopulmonary exercise testing in cardiology-referred patients with aortic stenosis with preserved systolic function appears to be associated with very low risk of major adverse cardiovascular events during testing.

Cardiac allograft hypertrophy is associated with impaired exercise tolerance after heart transplantation.

BACKGROUND: Exercise performance, an important aspect of quality of life, remains limited after heart transplantation (HTx). This study examines the effect of cardiac allograft remodeling on functional capacity after HTx. METHODS: The total cohort of 117 HTx recipients, based on echocardiographic determination of left ventricle mass and relative wall thickness at 1 year after HTx, was divided into 3 groups: (1) NG, normal geometry; (2) CR, concentric remodeling; and (3) CH, concentric hypertrophy. Cardiopulmonary exercise testing was performed 5.03 ± 3.08 years after HTx in all patients. Patients with acute rejection or significant graft vasculopathy were excluded. RESULTS: At 1 year post-HTx, 30% of patients had CH, 55% had CR and 15% had NG. Exercise tolerance, measured by maximum achieved metabolic equivalents (4.62 ± 1.44 vs 5.52 ± 0.96 kcal/kg/h), normalized peak Vo(2) (52 ± 14% vs 63 ± 12%) and Ve/Vco(2) (41 ± 17 vs 34 ± 6), was impaired in the CH group compared with the NG group. A peak Vo(2) ≤14 ml/kg/min was found in 6%, 22% and 48% of patients in the NG, CR and CH groups, respectively (p = 0.01). The CH pattern was associated with a 7.4-fold increase in relative risk for a peak Vo(2) ≤14 ml/kg/min compared with NG patients (95% confidence interval 1.1 to 51.9, p = 0.001). After multivariate analysis, a 1-year CH pattern was independently associated with a reduced normalized peak Vo(2) (p = 0.018) and an elevated Ve/Vco(2) (p = 0.035). CONCLUSIONS: The presence of CH at 1 year after HTx is independently associated with decreased normalized peak Vo(2) and increased ventilatory response in stable heart transplant recipients. The identification of CH, a potentially reversible mechanism of impairment in exercise capacity after HTx, may have major clinical implications.