Beef Cattle Feeding Operations Research Articles

USEPA CALPUFF validation and dispersion modeling of beef cattle feedlot PM10 and PM2.5 emissions factors

Beef cattle feedlots are major sources of criteria air pollutants in the United States. To aid stakeholders in air quality modeling, emissions factors for animal waste-producing facilities are under development by the U.S. Environmental Protection Agency (USEPA). However, beef cattle feeding operations (feedlots) are not among facilities surveyed under the associated USEPA National Air Emissions Monitoring Study (NAEMS). Authors aim to supplement NAEMS through development and validation of particulate matter (PM10 and PM2.5) emission factors from a previous sampling campaign of five large feedlots in the Southern High Plains of North America via USEPA's CALPUFF dispersion model. PM concentrations were higher overall during the warm season (March–August; PM10 = 692 ± 507, PM2.5 = 114 ± 110 μg/m3) relative to cool season (November–January; PM10 = 102 ± 105, PM2.5 = 12.2 ± 8.6 μg/m3), and overall median PM10 and PM2.5 emission factors were 48.2 (day = 33.8, night = 72.4) and 5.22 (day = 8.4, night = 3.1) mg/m2/hr, respectively. Validated emissions factors were then used to model diurnal peaks and long-range transport (100 km maximum extent). Peak concentrations were most frequently observed between 2000 and 0600 h (93.9%; mean 1-hr peak ± SD = 1119 ± 1240 μg/m3) for PM10 and 1600-0600 h (80.0%; mean 1-hr peak ± SD; 178 ± 174 μg/m3) for PM2.5. Four of five feedlots exceeded ≥1 primary PM National Ambient Air Quality Standard (NAAQS) at receptors (2-m height) over a 5-km spatial extent during the modeling period (November 2010–August 2011). Moreover, present estimates of feedlot-derived inhalable PM represent human and environmental exposure pathways currently exempt from Clean Air Act monitoring and reporting standards, and spatial interpolation of federal air quality monitors cannot adequately characterize inhalable PM concentrations in non-metropolitan municipalities and unincorporated rural communities.

Bee Pollinator Mortality Due to Pesticide-Laden Particulate Matter from Beef Cattle Feedyards.

Wild and managed bees are critical for the stability of trophic webs, angiosperm reproduction, and agricultural productivity. Unfortunately, as many as 40% of crop pollinators are in a steep decline due to habitat loss and exposure to agrochemicals. Pyrethroids, neonicotinoids, and macrocyclic lactones are among the many agrochemicals toxic to pollinating insects that are used extensively in industrial beef cattle feeding operations throughout the world. Fugitive feedyard particulate matter (PM) transports agrochemicals into the surrounding environs. To determine the impact of agrochemical-laden feedyard particulate matter on bee pollinators, we conducted in situ experiments wherein honeybees and mason bees were placed downwind and upwind of feedyards (N = 40). Concurrent, colocated total suspended particulate matter samples contained multiple insecticides and parasiticides including pyrethroids, neonicotinoids, and macrocyclic lactones, in significantly higher concentrations downwind of feedyards (bifenthrin, 8.45 ± 4.92; permethrin, 1032.34 ± 740.76; clothianidin, 3.61 ± 1.48; imidacloprid, 73.32 ± 47.52; thiamethoxam, 5.81 ± 3.16; abamectin, 0.45 ± 0.29; ivermectin, 8.88 ± 5.06 ng/g). Honeybees and mason bees sited downwind of feedyards always experienced higher mortality than those correspondingly sited upwind, and male mason bees experienced significantly higher mortality compared to females when both were sited downwind. Bees occurring downwind of beef cattle feedyards for 1 h are 232-260% more likely to die than those occurring upwind. Thus, agrochemicals used on and emitted from beef cattle feedyards are significant threats to bee pollinators.

Chronic Exposure to Two Gestagens Differentially Alters Morphology and Gene Expression in Silurana tropicalis.

Gestagens are active ingredients in human and veterinary drugs with progestogenic activity. Two gestagens-progesterone (P4), and the synthetic P4 analogue, melengestrol acetate (MGA)-are approved for use in beef cattle agriculture in North America. Both P4 and MGA have been measured in surface water receiving runoff from animal agricultural operations. This project aimed to assess the morphometric and molecular consequences of chronic exposures to P4, MGA, and their mixture during Western clawed frog metamorphosis. Chronic exposure (from embryo to metamorphosis) to MGA (1.7µg/L) or P4 + MGA (0.22µg/L P4 + 1.5µg/L MGA) caused a considerable dysregulation of metamorphic timing, as evidenced by an inhibition of growth, narrower head, and lack of forelimb emergence in all animals. Molecular analysis revealed that chronic exposure to the mixture induced an additive upregulation of neurosteroid-related (GABAA receptor subunit α6 (gabra6) and steroid 5-alpha reductase 1 (srd5α1) gene expression in brain tissue. Chronic P4 exposure (0.26µg/L P4) induced a significant upregulation of the expression hypothalamic-pituitary-gonadal (HPG)-related genes (ipgr, erα) in the gonadal mesonephros complex (GMC). Our data suggest that exposure to P4, MGA, and their mixture induces multiple endocrine responses and adverse effects in larval Western clawed frogs. This study helps to better our understanding of the consequences of chronic gestagen exposure and suggests that the implications and risk of high gestagen use in beef cattle feeding operations may extend to the aquatic environment.

Urease Inhibitor for Reducing Ammonia Emissions from an Open-Lot Beef Cattle Feedyard in the Texas High Plains

<abstract> Abstract. Reducing ammonia (NH3) emissions from animal feeding operations is important from the perspective of environmental policy and its impact on agriculture. In laboratory studies, urease inhibitors have been effective in reducing NH3 emissions from beef cattle manure, however there has been little testing under field conditions. An experiment was conducted to evaluate the effectiveness of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) for reducing NH3 flux from the pen surface at a beef cattle feedyard. NBPT was applied to six feedyard pens for 42 d (April-June) at rates of 0, 1, 2, 4, 8, and 40 kg ha-1. NH3 flux was quantified using a flow-through flux chamber and chemiluminescence NH3 analyzer. Nutrient concentrations in the manure were monitored over the 42 d period. There was high spatial variability in NH3 emissions within individual pen, and NH3 flux was lognormally distributed (geo. mean=1,618 μg m&-2 min&-1; geo. std. dev. = 2.52 μg m&-2 min&-1; range 512 to 14,993 μg m&-2 min&-1). No statistical differences were observed in NH3 flux among the different NBPT application rates due to the high spatial variability in NH3 flux within pens. A post&-experiment power analysis revealed that more than 500 individual flux chamber measurements would be needed per pen in order to detect a 10% difference in treatment means, an impractical task given the time and labor required for flux chamber measurements. At the completion of the six-week experiment, the 2 and 40 kg ha-1 NBPT treatments retained 9% and 20% more total Kjeldahl nitrogen (TKN) in the manure than the control, respectively. In future research evaluating the long-term effectiveness of urease inhibitors for reducing NH3 emissions from open-lot beef cattle feeding operations, we recommend that micrometeorological methods would be more appropriate than small flux .

Phosphorus downward movement in soil highly charged with cattle manure

In the rolling pampa region, the intensification of beef cattle feeding operations generates large volumes of solid organic manure which has high concentrations of phosphorus (P). This residue can be reused like organic fertilizer in agricultural practices, increasing crop production and closing the nutrients cycle. However, this practice can cause water pollution if not well managed. The aim was to study the vertical and temporal migration of P and its relations with edaphic properties in agricultural soil that has received a single heavy application of cattle manure. Three treatments were analyzed: (1) Zone 4 (Z4)—plot manured with 1600 tn ha−1 in 2004; (2) Zone 10 (Z10)—plot manured with 500 tn ha−1 in 2010 and (3) Zone control (ZC)—plot free of cattle manure. Water extractable phosphorus—WEP, soil test Bray and Kurtz P—Bray P, total phosphorus—TP, organic carbon—OC, pH and electrical conductivity were quantified. Results indicate high concentration of TP, Bray P and WEP in deeper horizons of impacted plots, showing the mobility of this nutrient. Correlation between TP and OC% were established for Z4 y Z10 in 88 and 84 %, demonstrating that the organic matter that moved in the profile presented high P content. An increase of salinity of 257 and 345 % for Z4 and Z10, respectively, was found in the deepest samples. The quantification of an empirical rate (EARP) showed the downward movement of P reaching 150 cm in Z4 and 90 cm in Z10. The results have shown that application of large volumes of solid manure saturated P retention capacity favoring its movement towards underlying water.

Use of Manure to Wheat Production in an Argentinean Hapludoll Soil

Beef cattle feeding operations or feedlots generate large amounts of manure that negatively affect the environment. In order to reach an integrated farming system, setting a final destiny for these wastes not to damage the environment, the use of cattle manure in partial or total replacement of inorganic fertilizers has been evaluated. The study was done in sub-humid, sandy pampas region, on an Entic Hapludoll soil. The field experiment was performed using wheat. Four treatments were carried out as follows: a control treatment on the one hand and other three treatments on the other, containing a 116 kg N ha-1 isodose: Inorganic Fertilization (IF), Manure (M) and a mixture of Manure and Inorganic Fertilizers (M-IF) in equal parts. Results show M-IF treatment as the most efficient one, because it had the highest yield with the least negative effects over the environment.

Uptake of 17β-trenbolone and subsequent metabolite trendione by the pinto bean plant (Phaseolus vulgaris)

Manure from livestock feeding operations is commonly applied to agricultural fields as an alternative to commercial fertilizers. Trenbolone acetate (TbA) is a synthetic growth promoter frequently utilized in beef cattle feeding operations. Metabolites of TbA can be present in manure and subsequently applied to fields. Fate ofTbA metabolites 17β-trenbolone (17βTb), 17α-trenbolone (17αTb), and trendione (TbO) have been assessed in manure and soils, but plant uptake in agricultural fields is not fully understood. The objective of this study was to investigate potential plant uptake and biotransformation of 17βTb using the pinto bean plant (Phaseolus vulgaris). Vegetated (n=20) and control sands (n=16) were amended with 17βTb at a level of 1μg/g once per week for a total of four weeks. Sand, above-ground plant portion and below-ground plant portion were collected each week and then analyzed for 17βTb, 17αTb, and TbO. By week four, low concentrations of 17βTb (10±4.9μg/g fresh weight) were taken up into the roots of plants and, to a much lesser extent, translocated throughout the plant (0.04±0.02μg/g fresh weight). Extensive transformation of 17βTb to the metabolite trendione (TbO) occurred in vegetated sand, while minimal TbO was detected in control sand. These results suggest the biotransformation of 17βTb to TbO is predominantly through microbial degradation. Trenbolone (Tb) metabolites can then be taken up into plants but remain concentrated in the roots with only slight translocation to above ground portions of the plant. After four weeks, maximum observed concentrations of total Tb (parent+metabolites) in fresh plant tissues were 33.0μg/g in roots and 0.25μg/g in leaves. No phytotoxicity was observed to pinto bean plants throughout the four week study.

Effect of Growth Promotants on the Occurrence of Endogenous and Synthetic Steroid Hormones on Feedlot Soils and in Runoff from Beef Cattle Feeding Operations

Supplements and growth promotants containing steroid hormones are routinely administered to beef cattle to improve feeding efficiency, reduce behavioral problems, and enhance production. As a result, beef cattle manure will contain both synthetic steroids as well as a range of endogenous steroids including androgens, estrogens, and progestogens. A two-year controlled study was conducted in which beef cattle were administered steroid hormones via subcutaneous implants and feed additives and the occurrence of 16 endogenous and synthetic steroid hormones and metabolites was evaluated in runoff from beef cattle feedlots and in manure and soil collected from feedlot surfaces. Samples were extracted and analyzed using liquid chromatography tandem mass spectrometryfor metabolites of the synthetic androgen trenbolone acetate, 17α-trenbolone, 17β-trenbolone, for the nonsteroidal semisynthetic estrogen agonist, α-zearalanol, and the synthetic progesterone melengesterol acetate, as well as a wide range of endogeneous estrogens, androgens, and fusarium metabolites. Synthetic steroids including trenbolone metabolites and melengestrol acetate were detected in fresh manure and in feedlot surface soils from cattle administered synthetic steroids at concentrations up to 55 ± 22 ng/g dry weight (dw) (17α-trenbolone) and 6.5 ± 0.4 ng/g dw (melengesterol acetate). Melengesterol acetate was detected in 6% of runoff samples from feedlots holding cattle administered synthetic steroids at concentrations ranging up to 115 ng/L. The presence of melengesterol acetate in runoff from beef cattle feeding operations has not been previously reported. Synthetic steroids were not detected in manure or runoff from control cattle. A wide range of endogenous hormones were detected in runoff and feedlot surface soils and manure from cattle given synthetic steroids and from control cattle, with no statistically significant differences in concentration. These results indicate that runoff from confined animal production facilities is of environmental and public health concern regardless of the use of growth promotants.

Liquid chromatography–tandem mass spectrometry analysis of 17α-trenbolone, 17β-trenbolone and trendione in airborne particulate matter

Trenbolone acetate (TbA) is a potent synthetic anabolic steroid that was approved by the FDA as a growth promoter in beef cattle in 1987. Given the endocrine-modulating activity of TbA and its metabolites in all vertebrates, a sensitive and reliable analytical method is needed to detect TbA and related residues in environmental matrices. We have developed a method that incorporates solid phase extraction and liquid chromatography–tandem mass spectrometry (LC–MS/MS) for the simultaneous determination of the three major TbA metabolites (trendione, 17β-trenbolone, 17α-trenbolone) in total suspended particulate matter (TSP) samples. Sample preparation involved pressurized liquid extraction followed by cleanup on solid-phase extraction cartridges. The procedure was optimized to obtain maximum recovery and minimum signal suppression/enhancement from matrix effects. Analytes were separated with a Phenomenex Gemini-NX C18 analytical column (150mm×2.0mm, 3μm particle size) using an aqueous methanol gradient at a flow rate of 0.2mL/min. Column effluent underwent positive electrospray ionization (ESI). Two or more diagnostic product ions were acquired from analyte specific precursor ions for unambiguous confirmation and quantification. The method detection limit was 3.27–4.87ng/g of particulate matter (PM). Method accuracy, determined with analyte recoveries, ranged between 68% and 117%, and method precision, expressed as relative standard deviation, was below 15% at spiked levels of 6.67, 33.3, and 167ng/g PM. Analysis of TSP samples demonstrated the presence of the target species associated with PM in the vicinity of beef cattle feeding operations.

Presence and Determination of Manure-borne Estrogens from Dairy and Beef Cattle Feeding Operations in Northeast China

Four estrogens in cattle feces collected from 24 dairy and beef feeding operations located in the northeast of China were investigated. The average concentration of 17α-estradiol, 17β-estradiol and estrone in dairy feces was 194.6, 104.4, and 262 μg/kg, respectively. While as to beef waste the mean content of 17α-estradiol, 17β-estradiol and estrone was 104.5, 67.7 and 216.4 μg/kg, respectively. Estriol was below the detection limit in all samples. The 17β-estradiol equivalents of all samples ranged from 45.8 to 926.1 μg/kg and dairy together with beef probably generated 16 times more estrogens than the human population in the study area.

Influence of oscillating dietary crude protein concentration on performance, acid-base balance, and nitrogen excretion of steers1,2,3

Decreasing dietary N inputs into beef cattle feeding operations could potentially decrease environmental concerns relating to air and water quality. Previous studies with sheep suggest that oscillating dietary CP concentrations may improve N use efficiency and thereby decrease dietary N requirements. Therefore, two studies were conducted to determine the effects of oscillating dietary CP concentrations on performance, acid-base balance, and manure characteristics of steers fed high-concentrate diets. Steers were fed to a constant backfat thickness in both studies. In the first trial, 92 steers (mean BW = 408 +/- 2.8 kg; four pens/treatment) were fed the following diets: 1) constant 12% CP, 2) constant 14% CP, and 3) 10 and 14% CP oscillated at 2-d intervals. Steer performance and carcass characteristics were measured. In the second trial, 27 steers were individually fed the same three experimental dietary regimens (nine steers/treatment). Animal performance, arterial acid-base balance, plasma metabolites, and fecal characteristics were measured. In both trials, steers fed the 14% CP diet tended (P < 0.10) to have greater ADG and gain:feed than steers fed the 12% CP diet. Steers fed the oscillating CP regimen had intermediate performance. In Trial 1, steers fed the 14% CP diet tended (P = 0.09) to have smaller longissimus area and higher quality grades than steers fed the oscillating CP regimen. Protein retentions (g/d) calculated from NRC (2000) equations were greater (P = 0.04) for steers fed the 14% CP diet than steers fed the 12% CP diet. Steers fed the oscillating CP regimen tended (P = 0.08) to have greater calculated protein retention (g/d) than steers fed the 12% CP diet. Steers fed the 14% CP diet had greater (P < 0.05) calculated urinary N excretion than steers fed the 12% CP or oscillating CP regimens. Venous plasma concentrations of urea N were greater (P < 0.001) in steers fed the 14% CP diet than in steers fed the 12% CP diet; steers fed the oscillating CP regimen were intermediate but fluctuated over days. Based on arterial blood gas concentrations, acid-base balance was not significantly affected by dietary CP regimen. Results of these trials suggest that the CP requirement of steers in these studies was greater than 12% of the diet DM, and/or that the degradable CP requirement was greater than 6.3% of diet DM. However, the effects of oscillating dietary CP were minimal.

PERFORMANCE OF A PASSIVE FEEDLOT RUNOFF CONTROL AND TREATMENT SYSTEM

The recent signing of the NPDES permit regulations and effluent limitations guidelines for CAFO has generated much interest from smaller beef cattle feeding operations for a more cost-effective solution for managing feedlot runoff. A passive runoff control and treatment system was constructed to reduce long-term liquid storage, provide solids separation, and evenly distribute the liquid discharge for grass hay production. The overall objective of this study was to evaluate the effectiveness of this passive system for reducing contaminant discharge. The system effectively reduced the cumulative mass of total and volatile suspended solids and reduced chemical oxygen demand by 80%, 67%, and 59%, respectively. Significant reductions of these constituents in the runoff water as it passed through the system were measured for most precipitation events. No water was measured exiting the vegetative filter strip during the three-year period of this study. Therefore, the discharge water was effectively contained and used for hay crop production. Estimated total nitrogen (TN) load in the discharge water entering the vegetative filter strip was equivalent to or less than the TN removed by the crop. System robustness was demonstrated during feedlot pen renovation when significant reductions in contaminant concentrations were measured for most all precipitation events during that period.

Environmental stewardship in the future: Nutrient management issues and options for beef cattle feeding operations

Environmental stewardship in the future: Nutrient management issues and options for beef cattle feeding operations