Beef Steer Performance on Irrigated Monoculture Legume Pastures Compared with Grass- and Concentrate-Fed Steers.

Fall- or spring-born steers grazed monoculture irrigated birdsfoot trefoil (BFT; Lotus corniculatus L.) or cicer milkvetch (CMV; Astragalus cicer L.) pastures for approximately 12 weeks for 3 years and were compared with steers on concentrate diets. In the 3rd year, an irrigated meadow bromegrass (MBG; Bromus biebersteinii Roem. and Schult.) pasture treatment was added for further comparison. Steer average daily gain (ADG) was 1.31, 0.94, 0.83 and 0.69 kg d−1 on concentrate, 'Norcen' BFT, 'Oberhaunstadter' BFT, and 'Monarch' CMV diets, respectively; ADG on grass pastures was 0.43 kg d−1. The ADG on the concentrate diet was greater than ADG on legume or grass pastures, ADG was greater on BFT than CMV in every year (p < 0.03), and ADG on BFT was greater than ADG on grass (p < 0.03). The rate constant of gas production of an in vitro rumen fermentation demonstrated a slower rate of microbial digestion for CMV than for BFT. The elevated ADG on BFT pastures may be due to greater non-fiber carbohydrate (NFC) concentration and reduced neutral detergent fiber (NDF) concentration combined with condensed tannins that protect proteins in the rumen but do not impede protein digestion in the abomasum and intestines.

Elemental composition and moisture prediction in manure by portable X-ray fluorescence spectroscopy using random forest regression.

Manure elemental composition determination is essential to develop farm nutrient budgets and assess environmental risk. Portable X-ray fluorescence (PXRF) spectrometers could facilitate hazardous waste-free, rapid, and cost-effective elemental concentration determinations. However, sample moisture is a problem for elemental concentration determination by X-ray methods. The objective of this study was to quantify the effect of sample moisture content, predict moisture content, and correct for moisture effect on elemental concentration determinations in livestock manure. Oven-dried manure samples (n = 40) were ground and adjusted to five moisture ranges of (w/w moisture) <10%, 10-20%, 20-30%, 40-50%, and 60-70%. Samples were scanned by PXRF for 180 s using a vacuum (<1,333 Pa) and without a filter. The presence of moisture negatively affected elemental determination in manure samples. Calibrations (n = 200) were prepared using random forest regression with detector channel counts as independent variables. A three-step validation was performed using all the data, random cross-validation and external validation. The back end of the spectrum (14-15 keV) had strong predictive power (r2  = .98) for moisture content. The random forest approach increased r2 between PXRF and wet chemical methods from <.66 to >.90 for P, K, and Mg and from .78 to .98 for Fe, compared with linear, nonlinear, and Lucas-Tooth and Price equations. These results indicated that elemental concentration can accurately be measured in dried and moist manure samples using PXRF and expands the potential applications of PXRF to in situ elemental determinations for agricultural and environmental samples.

Light Interception and the Growth of Pastures under Ideal and Stressful Growing Conditions on the Allegheny Plateau.

Pasture-based livestock production is impacted by management and weather. In pastures, there is conflict between leaf retention for plant growth and leaf harvest for animal nutrition. Defoliated pastures with low light interception (LI) may have a low forage growth rate (FGR), while excessive growth shades leaves, reducing FGR and resulting in an S-shaped regrowth curve. To optimize production, it is best to keep FGR linear. Three studies were conducted to evaluate the impact of management and weather on FGR. Replicated pastures were used to measure FGR when grazed from 25 to 10 cm and allowed to regrow. The impact of alternative defoliation timings and intensities on FGR were studied using clipped treatments at three recovery intervals and two stubble heights. Variability in FGR was studied using a field validated plant growth model. Of the 24 growth periods studied, two displayed exponential, 12 linear and 10 linear-plateau growth. There was no effect of FM on growth curve form. In May and June, LI increased with canopy height, up to 0.93. Stubble height and days of growth impacted FGR with an interaction. There was no treatment impact on root density. Weather caused variation in FGR. A low FGR risk occurs at high elevations; greater risk occurs east of the plateau.

Portable X-Ray Fluorescence Spectroscopy for Rapid and Cost-Effective Determination of Elemental Composition of Ground Forage.

The recent development of portable X-ray fluorescence spectrometers (PXRF) has created new avenues for rapid plant elemental concentration determination at reduced cost while avoiding hazardous chemicals. A few studies have indicated the potential use of PXRF for homogenous plant tissue analysis. However, there is a lack of information for analysis of heterogeneous plant samples like livestock forage, which consists of a mixture of several species and plant parts, each varying in elemental concentration. Our objective was to evaluate PXRF for forage analysis, specifically the effect of forage particle size and scan time on important elements including P, K, Ca, and Fe determination. Hay samples (n = 42) were oven dried (60°C for 3 days) and ground into three particle sizes (≤0.5 mm, 0.25-0.5 mm and 1-2 mm). Prepared samples were scanned by PXRF using a vacuum (<10 torr) without a filter. Samples were placed in cups over thin prolene X-ray film and scanned for 180 s. A subset (n = 29) were also scanned for 60 and 120 s. PXRF counts for P, K, Ca, and Fe were compared with laboratory Inductively Coupled Plasma Optical Emission Spectroscopy (ICP) determinations, using regression models. Results indicated that these elements could potentially be determined with PXRF (r 2 ≥ 0.70) in heterogeneous forage samples. Relationship strength increased with decreasing particle size, however, the relationship was still strong (r 2 ≥ 0.57) at the largest particle size. Scanning time did not affect the relationship with ICP concentration for any of the particle sizes evaluated. This work demonstrated that with the right sample preparation PXRF can obtain results comparable to acid digestion and ICP regardless of sample composition, and suggests the potential for in situ determinations.

Switchgrass yield on reclaimed surface mines for bioenergy production.

The high cost of transportation fuels and the environmental risks associated with acquiring and using nonrenewable energy sources have created a demand for developing renewable bioenergy crops. Switchgrass ( L.), a warm-season perennial grass, is a promising feedstock due to its high biomass production under a wide range of growing conditions and its satisfactory forage quality and chemical composition. West Virginia contains vast expanses of reclaimed surface mine lands that could be used to produce switchgrass as a bioenergy feedstock. This study determined dry matter yields of three switchgrass varieties (Cave-In-Rock, Shawnee, and Carthage) during the second to fourth years of production. Two research sites were established on reclaimed surface mines in southern West Virginia: Hobet and Hampshire. The Hobet site was prepared using crushed, unweathered sandstone as the soil material, and yields were significantly lower at 803 kg ha averaged across varieties and years than annual yields at Hampshire. The highest yield at Hobet, with Shawnee in the third year, was 1964 kg ha. The Hamphire site, which was reclaimed in the late 1990s using topsoil and treated municipal sludge, averaged 5760 kg ha of switchgrass across varieties and years. The highest yield, obtained with Cave-in-Rock during the third year, was 9222 kg ha. Switchgrass yields on agricultural lands in this region averaged 12,000 kg ha. Although average switchgrass yields at Hampshire were about 50% lower than agricultural lands, they were greater than a target yield of 5000 kg ha, a threshold for economically feasible production. Yields during the fourth year from a two-harvest per year system were not significantly different from a single, end-of-year harvest at both sites. Reclaimed lands show promise for growing bioenergy crops such as switchgrass on areas where topsoil materials are replaced and amended like that at the Hampshire site.

Porcine and canine von Willebrand factor and von Willebrand disease: hemostasis, thrombosis, and atherosclerosis studies.

Use of animal models of inherited and induced von Willebrand factor (VWF) deficiency continues to advance the knowledge of VWF-related diseases: von Willebrand disease (VWD), thrombotic thrombocytopenic purpura (TTP), and coronary artery thrombosis. First, in humans, pigs, and dogs, VWF is essential for normal hemostasis; without VWF bleeding events are severe and can be fatal. Second, the ADAMTS13 cleavage site is preserved in all three species suggesting all use this mechanism for normal VWF multimer processing and that all are susceptible to TTP when ADAMTS13 function is reduced. Third, while the role of VWF in atherogenesis is debated, arterial thrombosis complicating atherosclerosis appears to be VWF-dependent. The differences in the VWF gene and protein between humans, pigs, and dogs are relatively few but important to consider in the design of VWF-focused experiments. These homologies and differences are reviewed in detail and their implications for research projects are discussed. The current status of porcine and canine VWD are also reviewed as well as their potential role in future studies of VWF-related disorders of hemostasis and thrombosis.

Intraarterial therapy for acute ischemic strokes.

PURPOSE: To determine the safety and feasibility of intraarterial stroke therapy for acute ischemic strokes at a community-based medical center. MATERIALS AND METHODS: This is a retrospective analysis of data gathered from consecutive stroke patients treated between June 2004 and April 2007. The following therapies were used to treat acute ischemic stroke within 6 hours of symptom onset: intraarterial thrombolytic drugs, intraarterial vasodilators, mechanical clot retrieval, intravascular stents, and angioplasty. The outcomes measured included posttherapy National Institutes of Health Stroke Score (NIHSS), neurologic function at 90 days graded according to the modified Rankin Scale (mRS), recanalization, symptomatic intracranial hemorrhage, and 90-day mortality. RESULTS: Eighty-three patients with a median baseline NIHSS of 17 (range, 3-30) were treated with intraarterial therapy. The median posttherapy NIHSS was 5 (range, 0-33). Forty-two patients (51%) [corrected] had an mRS score of 2 or less at 90 days. The recanalization rate was 76%. Five patients (6%) had symptomatic intracranial hemorrhage, and the 90-day mortality was 22%. CONCLUSIONS: The results of this review showed that an intraarterial therapeutic approach to acute ischemic stroke was feasible at a community-based heath center and demonstrated encouraging data for outcome and safety.

Effect of the September 11, 2001 terrorist attack on a state highway patrol trooper's heart rate variability.

BACKGROUND: On September 11, 2001, terrorists attacked the United States. By coincidence, a North Carolina highway patrol trooper was wearing an ambulatory ECG Holter monitor at this time as part of an air pollution study. METHODS: Heart rate variability parameters were analyzed: standard deviation of normal to normal beat intervals (SDNN) and percentage of interval differences >50 ms (PNN50). RESULTS: The trooper's heart rate variability changed immediately after learning about the terrorist attacks. Heart rate increased and PNN50 decreased, while SDNN increased strongly. CONCLUSIONS: These changes suggest strong emotional sympathetic stress associated with parasympathetic withdrawal in response to the news about the terrorist attack.

Particulate matter exposure in cars is associated with cardiovascular effects in healthy young men.

Exposure to fine airborne particulate matter (PM(2.5)) is associated with cardiovascular events and mortality in older and cardiac patients. Potential physiologic effects of in-vehicle, roadside, and ambient PM(2.5) were investigated in young, healthy, nonsmoking, male North Carolina Highway Patrol troopers. Nine troopers (age 23 to 30) were monitored on 4 successive days while working a 3 P.M. to midnight shift. Each patrol car was equipped with air-quality monitors. Blood was drawn 14 hours after each shift, and ambulatory monitors recorded the electrocardiogram throughout the shift and until the next morning. Data were analyzed using mixed models. In-vehicle PM(2.5) (average of 24 microg/m(3)) was associated with decreased lymphocytes (-11% per 10 microg/m(3)) and increased red blood cell indices (1% mean corpuscular volume), neutrophils (6%), C-reactive protein (32%), von Willebrand factor (12%), next-morning heart beat cycle length (6%), next-morning heart rate variability parameters, and ectopic beats throughout the recording (20%). Controlling for potential confounders had little impact on the effect estimates. The associations of these health endpoints with ambient and roadside PM(2.5) were smaller and less significant. The observations in these healthy young men suggest that in-vehicle exposure to PM(2.5) may cause pathophysiologic changes that involve inflammation, coagulation, and cardiac rhythm.

Cardiovascular effects in patrol officers are associated with fine particulate matter from brake wear and engine emissions.

BACKGROUND: Exposure to fine particulate matter air pollutants (PM2.5) affects heart rate variability parameters, and levels of serum proteins associated with inflammation, hemostasis and thrombosis. This study investigated sources potentially responsible for cardiovascular and hematological effects in highway patrol troopers. RESULTS: Nine healthy young non-smoking male troopers working from 3 PM to midnight were studied on four consecutive days during their shift and the following night. Sources of in-vehicle PM2.5 were identified with variance-maximizing rotational principal factor analysis of PM2.5-components and associated pollutants. Two source models were calculated. Sources of in-vehicle PM2.5 identified were 1) crustal material, 2) wear of steel automotive components, 3) gasoline combustion, 4) speed-changing traffic with engine emissions and brake wear. In one model, sources 1 and 2 collapsed to a single source. Source factors scores were compared to cardiac and blood parameters measured ten and fifteen hours, respectively, after each shift. The "speed-change" factor was significantly associated with mean heart cycle length (MCL, +7% per standard deviation increase in the factor score), heart rate variability (+16%), supraventricular ectopic beats (+39%), % neutrophils (+7%), % lymphocytes (-10%), red blood cell volume MCV (+1%), von Willebrand Factor (+9%), blood urea nitrogen (+7%), and protein C (-11%). The "crustal" factor (but not the "collapsed" source) was associated with MCL (+3%) and serum uric acid concentrations (+5%). Controlling for potential confounders had little influence on the effect estimates. CONCLUSION: PM2.5 originating from speed-changing traffic modulates the autonomic control of the heart rhythm, increases the frequency of premature supraventricular beats and elicits pro-inflammatory and pro-thrombotic responses in healthy young men.

Exposure to particulate matter, volatile organic compounds, and other air pollutants inside patrol cars.

People driving in a vehicle might receive an enhanced dose of mobile source pollutants that are considered a potential risk for cardiovascular diseases. The exposure to components of air pollution in highway patrol vehicles, at an ambient, and a roadside location was determined during 25 work shifts (3 p.m. to midnight) in the autumn of 2001, each day with two cars. A global positioning system and a diary provided location and activity information. Average pollutant levels inside the cars were low compared to ambient air quality standards: carbon monoxide 2.7 ppm, nitrogen dioxide 41.7 microg/m3, ozone 11.7 ppb, particulate matter smaller 2.5 microm (PM2.5) 24 microg/m3. Volatile organic compounds inside the cars were in the ppb-range and showed the fingerprint of gasoline. PM2.5 was 24% lower than ambient and roadside levels, probably due to depositions associated with the recirculating air conditioning. Levels of carbon monoxide, aldehydes, hydrocarbons, and some metals (Al, Ca, Ti, V, Cr, Mn, Fe, Cu, and Sr) were highest in the cars, and roadside levels were higher than ambient levels. Elevated pollutant levels were related to locations with high traffic volumes. Our results point to combustion engine emissions from other vehicles as important sources of air pollutants inside the car.