Energy and Nutrient Recovery fromCattle Feedlots

Selective harvesting of manure can benefit cattle producers by creating a product of value. A tool that identifies locations of manure accumulation has been developed using a subsurface sensor (Dualem-1S, Milton, ON) and software designed for salt mapping (ESAP, Riverside, CA). The combination allowed the development of models to estimate higher heating value (HHV) of feedlot manure across a feedlot pen. Soil sample data from cattle feedlots in Texas and Nebraska were analyzed for volatile solids (VSs) then combined with the Dualem-1S apparent soil conductivity (ECa) data to produce models having correlations between associated ECa values and VS (r2 = 0.869, VS). A corresponding model is under development to estimate the moisture content of the collectable solids. The combined models allow real-time spatial estimates of HHV within a feedlot pen. These methods will allow direct harvesting of VS for use as a recoverable energy source through direct combustion or cocombustion

Energy and Nutrient Recovery fromCattle Feedlots

Selective harvesting of manure can benefit cattle producers by creating a product of value. A tool that identifies locations of manure accumulation has been developed using a subsurface sensor (Dualem-1S, Milton, ON) and software designed for salt mapping (ESAP, Riverside, CA). The combination allowed the development of models to estimate higher heating value (HHV) of feedlot manure across a feedlot pen. Soil sample data from cattle feedlots in Texas and Nebraska were analyzed for volatile solids (VSs) then combined with the Dualem-1S apparent soil conductivity (ECa) data to produce models having correlations between associated ECa values and VS (r2 = 0.869, VS). A corresponding model is under development to estimate the moisture content of the collectable solids. The combined models allow real-time spatial estimates of HHV within a feedlot pen. These methods will allow direct harvesting of VS for use as a recoverable energy source through direct combustion or cocombustion

Manure Harvesting Frequency: The Key to Feedyard Dust Control in a Summer Drought

4 pp., 4 photosSummer drought can make dust control in feedyards more challenging than usual. Supplemental water may not keep pace with daily evaporation. The key to dust control is managing the depth of dry manure in the pens by harvesting manure more frequently, and planning ahead when a drought is projected

High concentrations of coarse particles emitted from a cattle feeding operation

Housing roughly 10 million head of cattle in the United States alone, open air cattle feedlots represent a significant but poorly constrained source of atmospheric particles. Here we present a comprehensive characterization of physical and chemical properties of particles emitted from a large representative cattle feedlot in the Southwest United States. In the summer of 2008, measurements and samplings were conducted at the upwind and downwind edges of the facility. A series of far-field measurements and samplings was also conducted 3.5 km north of the facility. Two instruments, a GRIMM Sequential Mobility Particle Sizer (SMPS) and a GRIMM Portable Aerosol Spectrometer (PAS), were used to measure particle size distributions over the range of 0.01 to 25 μm diameter. Raman microspectroscopy was used to determine the chemical composition of particles on a single particle basis. Volume size distributions of dust were dominated by coarse mode particles. Twenty-four hour averaged concentrations of PM<sub>10</sub> (particulate matter with a diameter of 10 μm or less) were as high as 1200 μg m<sup>−3</sup> during the campaign. The primary constituents of the particulate matter were carbonaceous materials, such as humic acid, water soluble organics, and less soluble fatty acids, including stearic acid and tristearin. A significant fraction of the organic particles was present in internal mixtures with salts. Basic characteristics such as size distribution and composition of agricultural aerosols were found to be different than the properties of those found in urban and semi-urban aerosols. Failing to account for such differences may lead to errors in estimates of aerosol effects on local air quality, visibility, and public health

Laboratory and field studies of ice-nucleating particles from open-lot livestock facilities in Texas

In this work, an abundance of ice-nucleating particles (INPs) from livestock facilities was studied through laboratory measurements from cloud-simulation chamber experiments and field investigation in the Texas Panhandle. Surface materials from two livestock facilities, one in the Texas Panhandle and another from McGregor, Texas, were selected as dust proxies for laboratory analyses. These two samples possessed different chemical and biological properties. A combination of aerosol interaction and dynamics in the atmosphere (AIDA) measurements and offline ice spectrometry was used to assess the immersion freezing mode ice nucleation ability and efficiency of these proxy samples at temperatures above −29 ∘C. A dynamic filter processing chamber was also used to complement the freezing efficiencies of submicron and supermicron particles collected from the AIDA chamber. For the field survey, periodic ambient particle sampling took place at four commercial livestock facilities from July 2017 to July 2019. INP concentrations of collected particles were measured using an offline freezing test system, and the data were acquired for temperatures between −5 and −25 ∘C. Our AIDA laboratory results showed that the freezing spectra of two livestock dust proxies exhibited higher freezing efficiency than previously studied soil dust samples at temperatures below −25 ∘C. Despite their differences in composition, the freezing efficiencies of both proxy livestock dust samples were comparable to each other. Our dynamic filter processing chamber results showed on average approximately 50 % supermicron size dominance in the INPs of both dust proxies. Thus, our laboratory findings suggest the importance of particle size in immersion freezing for these samples and that the size might be a more important factor for immersion freezing of livestock dust than the composition. From a 3-year field survey, we measured a high concentration of ambient INPs of 1171.6 ± 691.6 L−1 (average ± standard error) at −25 ∘C for aerosol particles collected at the downwind edges of livestock facilities. An obvious seasonal variation in INP concentration, peaking in summer, was observed, with the maximum at the same temperature exceeding 10 000 L−1 on 23 July 2018. The observed high INP concentrations suggest that a livestock facility is a substantial source of INPs. The INP concentration values from our field survey showed a strong correlation with measured particulate matter mass concentration, which supports the importance of size in ice nucleation of particles from livestock facilities.</p

Energy and Nutrient Recovery fromCattle Feedlots

Selective harvesting of manure can benefit cattle producers by creating a product of value. A tool that identifies locations of manure accumulation has been developed using a subsurface sensor (Dualem-1S, Milton, ON) and software designed for salt mapping (ESAP, Riverside, CA). The combination allowed the development of models to estimate higher heating value (HHV) of feedlot manure across a feedlot pen. Soil sample data from cattle feedlots in Texas and Nebraska were analyzed for volatile solids (VSs) then combined with the Dualem-1S apparent soil conductivity (ECa) data to produce models having correlations between associated ECa values and VS (r2 = 0.869, VS). A corresponding model is under development to estimate the moisture content of the collectable solids. The combined models allow real-time spatial estimates of HHV within a feedlot pen. These methods will allow direct harvesting of VS for use as a recoverable energy source through direct combustion or cocombustion

Proposed Beef Cattle Manure Excretion and Characteristics Standard for ASAE

A committee was formed consisting of both animal scientists and agricultural engineers to evaluate and update current ASAE standards. An intake minus retention model was developed to estimate nutrient excretion. This approach allows users (producers, engineers, etc.) to develop site specific information based on known variables such as protein or phosphorus content of diets and cattle performance. This approach illustrates the importance of nutrition on nutrient excretion in livestock operations. Our focus is for feedlot cattle and updates excretion of dry matter (DM or total solids), organic matter (OM or volatile solids), N, P, Ca, K, Na, Mg, S, Cu, Fe, Se, Zn, Mn, Co, and I. Based on survey data of 19 nutritionists that control formulation for approximately 50% of the cattle fed in the U.S., the average diet contains 13.3% crude protein (2.13% N) and 0.31% P. Based on performance of approximately 14 million cattle fed from 1996 to 2002, the average steer is fed 153 days. This steer weighs 338 kg at arrival, finishes at 554 kg, gains 1.42 kg per day and consumes 8.84 kg of DM each day. With the average diet concentrations and consumption amounts for feedlot steers fed in the U.S, we can accurately estimate nutrient intake. Retention of nutrients in the animal during growth is the other critical component to using an intake minus retention based model for excretion. Retention of nutrients was calculated from gains using the 1996 National Research Council Nutrient Requirements of Beef Cattle to calculate N, P, and Ca retention. Retention of other minerals was based on 10% of intake being retained when fed at requirements. Average excretion values for DM, OM, N, P, Ca, K, Na, Mg, S, Cu, Fe, Se, Zn, Mn, Co, and I expressed for the entire 153 day period or per finished steer are 270 kg, 220 kg, 24.8 kg, 3.2 kg, 7.8 kg, 9.2 kg, 1.8 kg, 2.7 kg, 2.4 kg, 19.4 g, 68.9 g, 0.27 g, 96.1 g, 49.1 g, 0.31 g, and 0.93 g, respectively. In some cases, the new values are much lower than current standards. For example, P excretion is 6.3 kg for the average steer weighing 446 kg (average live weight) fed 153 days based on the previous standard. The revised P excretion based on intake minus retention is 3.2 kg or 50.8% of the previous standard. The proposed excretion values should allow for more accurate planning and allow users to tailor excretion to site-specific situations by incorporating cattle performance, days on feed, weights, and nutrient content of diets. While the previous standard does not account for variation, considerable agreement was found between the current intake minus retention model for excretion and the previous standard. Excretion of DM, OM, P, and Ca were identical between the average excretion estimate using the current model and the previous standard for calves gaining 0.9 kg per day, weighing 295 kg

Ammonia Concentration and Modeled Emission Rates from a Beef Cattle Feedyard

The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect the official position of the American Society of Agricultural and Biological Engineers (ASABE), and its printing and distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not subject to the formal peer review process by ASABE editorial committees; therefore, they are not to be presented as refereed publications. Citation of this work should state that it i