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Bedding is used in livestock operations to facilitate manure management and provide comfort for the animal. Our research objective was to determine differences in ammonia (NH 3 ), carbon dioxide (CO 2 ), nitrous oxide (N 2 O), and methane (CH 4 ) concentrations from simulated beef cattle bedded manure packs (BP) related to storage length (0 to 3, 3 to 6, and 6 to 9 weeks), bedding material (corn stover (CS) or soybean stubble (SB)), and temperature (10°C or 40°C). Bedding, fecal material, and urine were added weekly to 24 laboratory-scale BP (n = 2 per treatment combination). Static flux chamber samples from BP headspace were analyzed for CO 2 , N 2 O, and CH 4 at 0, 24, 46, and 144 h and for NH 3 at 0, 5, 9, 23, 34, 46, and 144 h after weekly manure and bedding addition for three consecutive weeks using a doubly repeated measures design. Ammonia concentrations were three times higher above BP in the Hot chamber (1190 ppm, SE = 47) compared to the Cold chamber (400 ppm, SE = 9). Average concentrations for CO 2 (6033 ppm, SE = 211), CH 4 (42 ppm, SE = 4), and N 2 O (0.61 ppm, SE = 0.05) were approximately twice as high at 40°C as for CO 2 (3902 ppm, SE = 161), CH 4 (21 ppm, SE = 2), and N 2 O (0.39 ppm, SE = 0.03) at 10°C. At 40°C, NH 3 concentrations above CS treatments (1388 ppm, SE = 75) were higher than above SB treatments (992 ppm, SE = 51). Overall, a higher storage temperature increased all gas concentrations. Increases in concentrations with length of storage were detected for CH 4 and CO 2 , while bedding affected NH 3 at 40°C and impacted changes in increase for CH 4 concentrations. These data suggest that seasonal management decisions can impact gas production and release in barns using BP. During hot months, NH 3 , CO 2 , CH 4 , and N 2 O concentrations are expected to increase and when applying CS as the bedding, NH 3 concentrations will likely be higher with CS bedding compared with SB bedding. At temperatures around 10°C, CO 2 and CH 4 concentrations are anticipated to increase with longer storage lengths.

In conjunction with an emission monitoring study, long-term airflow and environmental data were collected from select pens in each of four regional producer owned and operated mono-slope beef cattle facilities in the Northern Great Plains. The barns were oriented east-west, with approximate depths of 30 m in the north-south dimension, 82 to 333 m widths in the east-west dimension, and south and north wall eave heights of 8 and 5 m, respectively. The north wall curtain openings were adjusted by the producers seasonally or daily, and classified as open (>1.5 m, mean ±SD = 2.1 m ±0.1 m) or closed ( -1 south wind, there were approximately 10 to 70 air changes per hour (ACH) for closed conditions in the four barns, and 160 ACH with open curtains. The average relationships between airflow through the pen volume and ambient wind velocity were 7 and 33 ACH (m s -1 ) -1 for closed and open conditions, respectively. These data assist producers in management decisions, and are required for aerial pollutant estimation for this type of beef cattle facility in the Northern Great Plains.

Increasing demand for seafood products and rising demand for fish meal for commercial fish feeds is driving the search for effective alternative protein sources. Twin-screw extrusion trials were conducted to study the production of nutritionally balanced feeds for rainbow trout fingerlings (Oncorhynchus mykiss). Six isocaloric (≈4.61 kcal/g) ingredient blends with a target protein content of >45% db were formulated with 0, 10, 20, 30, 40, and 50% distillers dried grains with solubles (DDGS) and other feed ingredients. The moisture contents of the diets were initially adjusted to 5–7% db, and then extruded at 250 rpm using dual 1.9 mm dies with varying amounts of steam (7.2–7.7 kg/hr) injected into the conditioner and water (4.3–6.5 kg/hr) into the extruder. Mass flow rates, moisture contents, and temperatures were measured during processing and moisture content, water activity, unit density, bulk density, expansion ratio, compressive strength, compressive modulus, pellet durability index, water s...

Increases in global aquaculture production, com- pounded with limited availabilities of fish meal for fish feed, has created the need for alternative protein sources. Twin- screw extrusion studies were performed to investigate the production of nutritionally balanced feeds for juvenile yellow perch (Perca flavescens). Five isocaloric (~3.06 kcal/g) ingredient blends, adjusted to a target protein content of 36.7% db, were formulated with 0%, 10%, 20%, 30%, and 40% distillers dried grains with solubles (DDGS) at an initial moisture content of 5-7%db, with appropriate amounts of fish meal, fish oil, whole wheat flour, corn gluten meal, and vitamin and mineral premixes. During processing, varying amounts of steam (6.9-9.7 kg/h) were injected into the conditioner and water (6.7-13.1 kg/h) into the extruder to modulate the cohesiveness of the final extrudates. Extrusion cooking was performed at 226-298 rpm using a 1.9 mm die. Mass flow rate and processing temperatures generally decreased with progressively higher DDGS content. Mois- ture content, water activity, unit density, bulk density, expansion ratio, compressive strength and modulus, pellet durability index, water stability, angle of repose, and color were extensively analyzed to quantify the effects of varying DDGS content on the physical properties of the final extrudates. Significant differences (P

Due to tremendous increases in global aquaculture production, compounded with limited availabilities of fish meal for fish feed, the need for alternative protein sources cannot be disregarded. Toward that end, twin-screw extrusion studies were performed to investigate the production of nutritionally-balanced feeds for juvenile yellow perch (Perca flavescens). Five isocaloric (~ 3.06 kcal/g) ingredient blends, adjusted to a similar protein content of 36.7% db, were formulated with 0, 10, 20, 30, and 40% distillers dried grains with solubles (DDGS) at an initial moisture content of 5-7% db, with appropriate amounts of fish meal, fish oil, whole wheat flour, corn gluten meal, and vitamin and mineral mix. During processing, varying amounts of steam (6.9-9.7 kg/h) were injected into the conditioner and water (6.7-13.1 kg/h) into the extruder to modulate the cohesiveness of the final extrudates. Extrusion cooking was performed at 226-298 rpm using a 1.9 mm die. During processing, the mass flow rate and processing temperatures were determined (which generally decreased with progressively higher DDGS content). Additionally, moisture content, water activity, unit density, bulk density, expansion ratio, compressive strength and modulus, pellet durability index, water stability, angle of repose, and color were extensively analyzed to quantify the effects of varying DDGS content on the physical properties of the final extrudates. Significant differences (P

Besides significant nitrogen (N) losses through ammonia, N can also be lost as nitrous oxide (N 2 O) via microbial incomplete nitrification and denitrification in the manure. We conducted lab-scale experiments to determine N 2 O, denitrification enzyme activity (DEA) and nitrification activity potential (NAP) in simulated beef cattle bedded manure packs (BP) under different conditions. Thirty-six BP were stored in humidity-controlled chambers at 10°C or 40°C, contained either corn stover or soybean stubble as the bedding material, and were 0-3, 3-6 and 6-9 week old. The DEA and NAP were measured weekly before material addition. Samples were taken from varying depths based on BP age, and incubated at room temperature with different reagents and distilled water. For DEA, subsamples were analyzed for both nitrite N and combined nitrite-nitrate N consumption over 56 h of incubation. For NAP, samples were measured for nitrite production over 144 h. Results showed that NAP (1.22 nmol g bedpack -1 h -1 , SE = 0.10) was much lower (1000 fold) than DEA (1.93 mmol g bedpack -1 h -1 , SE = 0.14). The DEA was similar throughout BP depth, whereas NAP was higher in BP middle section. Nitrifiers are slow growing microorganisms which may explain low NAP in BP, whereas denitrifiers are fast growing communities that can survive in aerobic and anaerobic environments. Surface gas fluxes were measured with static flux chambers (n=2 per treatment). Nitrous oxide concentrations were on average 0.50 ppm (SE = 0.03) with peak concentrations occurring as high pulses right after material addition. Nitrous oxide production was most likely caused by incomplete denitrification from pulse nitrate concentrations available in the dried bedding material. However, future research using specific inhibitors or stable N isotopes should verify which process, nitrification or denitrification, is responsible for N 2 O production.

Mono-slope beef cattle facilities are an increasingly common housing system in the Northern Great Plains region of the U.S. Producers may maintain a deep-bedded manure pack (pack system), remove all bedding and manure from the pens weekly (scrape system), or use a combination of management styles. The objectives of this research were to determine baseline particulate matter (PM) concentrations around the immediate barn perimeter and to identify relationships between management practices and PM concentrations. PM was measured over two five-day periods at one pack system barn to determine differences in PM concentration between routine operation and a bedding event. The overall mean concentration of total suspended particulates (TSP) in the pack barn was 58.6 ±3.9 I¼g m -3 during routine operation and 702.2 ±3.9 I¼g m -3 during bedding events. The mean concentrations of PM less than 10 I¼m in diameter (PM 10 ) and PM less than 2.5 I¼m in diameter (PM 2.5 ) were 4.9 ±3.0 I¼g m -3 and 17.5 ±12.1 I¼g m -3 , respectively, during routine operation and 29.7 ±4.6 I¼g m -3 and 141.7 ±18.9 I¼g m -3 , respectively, during a bedding event. The PM concentrations returned to baseline within 18 h following a bedding event. In two scrape system barns, 24 h collections of PM 10 and PM 2.5 occurred at least twice during each quarter during a 14-month period. Daily mean concentrations of PM 2.5 and PM 10 in the scrape barns ranged from 10 to 14 I¼g m -3 and from 25 to 28 I¼g m -3 , respectively, indicating relatively low PM concentrations from mono-slope beef facilities. Ambient air temperature affected PM concentration, while relative humidity, number of cattle, and wind speed were less influential on overall dust in the facilities.

Demands for seafood products are steadily increasing. Alternative protein sources are required to compensate for enormous amounts of fishmeal that is needed for global seafood production. Starch is a food polymer that can be added to fish feed formulations to enhance binding and expanding capabilities of extrudates. Floatability, a key factor for most aqua feeds, can be optimized by the addition of certain starch sources. Six ingredient blends with a similar protein content (~32.5%) containing two starch sources, Hylon VII (containing 70% amylose, 30% amylopectin) or Waxy I (containing 0% amylose, 100% amylopectin), 20% distillers dried grain with solubles (DDGS), and 15, 25, and 35% moisture content were used along with appropriate amounts of soybean meal, menhaden fishmeal, whey, vitamin and mineral mix to investigate nutritionally-balanced feeds for Nile tilapia (Oreochromis niloticus L.). The blends were processed using a laboratory single-screw extruder with varying temperature settings (90-90-90°C, 100-120-120°C, and 100-120-140°C), screw speeds (100, 120, and 140 rpm), and length/diameter ratio (3.4, 6.6, 9.2) of the die. Extensive analyses of expansion ratio (ER), unit density (UD), sinking velocity (SV), and pellet durability indices (PDI), water absorption (WAI) and water solubility indices (WSI) were conducted to evaluate the effects of the two starch sources on extrudate binding and floating capacity. By varying process conditions, significant differences (P>0.05) among the blends were detected for all extrudate physical properties. Significantly higher values for ER, UD, and PDI were achieved by using the Waxy I starch source, while values for SV and WAI decreased. For WSI no significant differences were detected. Increasing the moisture content from 15-35% resulted in a significant increase in ER, WAI, and PDI and a significant decrease in UD. WSI showed no clear pattern in changes. The impact of different amylopectin to amylose ratio, temperature and moisture content on extrudate stability, cohesion and physical properties was demonstrated in this study. All formulations yielded viable extrudates while the blends with the amylopectin as the sole source of starch resulted in higher quality extrudates.

A single-screw laboratory extruder was used to conduct an L18 (22 X 36) Taguchi fractional factorial study of aquafeed processing. The ingredients were based on a formulation for nutritionally-balanced Nile tilapia diets containing distillers dried grains with solubles (DDGS) and soybean meal as the main protein sources, in addition to constant amounts of corn flour, whey, and fish meal. The effects of three levels of DDGS (20, 30 and 40%), soybean meal (30, 40 and 50%), ingredient moisture content (20, 30 and 40% db), screw speed (100, 150 and 200 rpm), barrel temperatures (80-100-100°C, 80-120-120°C and 80-140-140°C), and die dimensions (L/D ratios of 5, 9 and 13), and two levels of screw configuration (compression ratios of 2:1 and 3:1) on extrudate physical properties (moisture content, water activity, color, bulk density, unit density, pellet durability index, expansion ratio, water stability, water absorption and solubility indices) and extruder processing parameters (resulting temperatures, extruder torque, die pressure, mass flow rate, and specific mechanical energy) were determined. Data from raw materials, processing conditions, and extrudate properties were used to develop surface response curves and equations. However, predominantly low R2 values (< 0.5) only permitted linear relationships between some independent parameters and response variables. Regarding main effects, die pressure significantly decreased with higher DDGS levels, moisture content, temperature, lower die L/D, and higher screw compression. Significant differences in color were caused by changes in DDGS levels and moisture content. Expansion ratio decreased significantly with higher moisture content and lower die L/D. In summary, DDGS, moisture content, die dimension, and the extruder had the biggest impact on most of the extrudate physical properties and processing conditions. Different combinations of these independent factors can be used to achieve desired extrudate physical properties and processing conditions.

The world’s increasing demand for seafood products has resulted in rising demands for fish meal for fish feed, which must be compensated for by searching for effective alternative protein sources. In this study, twin-screw extrusion trials were conducted to study the production of nutritionally-balanced feeds for rainbow trout fingerlings (Oncorhynchus mykiss). Six isocaloric (~ 4.61 kcal/g) ingredient blends with a similar protein content of 52.8% db were formulated with 0, 10, 20, 30, 40 and 50% distillers dried grains with solubles (DDGS) and other ingredients (i.e. fish meal, fish oil, whole wheat flour, corn gluten meal, and vitamin and mineral mix). The moisture contents of the diets were initially adjusted to 5-7% db, and then extruded at 250 rpm using dual dies of 1.9 mm die with varying amounts of steam (7.2-7.7 kg/h) injected into the conditioner and water (4.3-6.5 kg/h) into the extruder. The mass flow rates, moisture contents, and temperatures were measured during processing. Additionally, moisture content, water activity, unit density, bulk density, expansion ratio, compressive strength, compressive modulus, pellet durability index, water stability, angle of repose, and color were extensively analyzed to quantify the effects of varying DDGS content on the physical properties of the final extrudates. Significant differences (P

This study was conducted to investigate the production of balanced diets for juvenile yellow perch (Perca flavescens) feeds. Six isocaloric (~ 3.21 kcal/g), isonitrogenous (31.5% db) ingredient blends were formulated with 0, 10, 20, 30, 40, and 50% distillers dried grains with solubles (DDGS) at a feed moisture content of 60-65% db, with appropriate amounts of soybean meal, fish meal, vitamin and mineral mix. Extrusion cooking was performed using a laboratory-scale single screw extruder at a constant barrel temperature profile of 40oC-90oC-100oC, and a constant screw speed of 230 rpm (24.1 rad/s). During processing the mass flow rate was determined, which generally increased with progressively higher DDGS content. Additionally, moisture content, water activity, unit density, expansion ratio, compressive strength, compressive modulus, pellet durability index, water stability and color were extensively analyzed to quantify the effects of varying DDGS content on the physical properties of the final extrudates. Significant differences (P

A single-screw laboratory extruder was used to conduct an L18 (22 ´ 36) Taguchi fractional factorial study of aquafeed processing. The ingredients were based on a formulation for nutritionally-balanced Nile tilapia diets containing distillers dried grains with solubles (DDGS) and soybean meal as the main protein sources, in addition to constant amounts of corn flour, whey, and fishmeal. The effects of three levels of DDGS (20, 30 and 40%), soybean meal (30, 40 and 50%), ingredient moisture content (20, 30 and 40% db), screw speed (100, 150 and 200 rpm), die dimension (L/D ratios of 5, 9 and 13), barrel temperature (80-100-100°C, 80-120-120°C and 80-140-140°C) and two levels of screw configuration (compression ratios of 2:1 and 3:1) on extrudate physical properties (moisture content, water activity, bulk density, unit density, expansion ratio, pellet durability index, water absorption and solubility indices, water stability, color) and extruder processing parameters (resulting temperatures, die pressure, extruder torque, mass flow rate, apparent viscosity, and specific mechanical energy) were determined. Data from raw materials, processing conditions, and extrudate properties were used to develop surface response curves and equations. However, predominantly low R2 values (< 0.5) only permitted linear relationships between some independent parameters and response variables. Regarding main effects, die pressure significantly decreased with higher DDGS levels, moisture content, temperature, lower die L/D, and higher screw compression. Expansion ratio decreased significantly with higher moisture content and lower die L/D. Significant differences in color were caused by changes in DDGS levels and moisture content. In summary, DDGS, moisture content, die dimension, and extrusion conditions had the biggest impact on most of the extrudate physical properties and processing conditions. Different combinations of these independent factors can be used to achieve desired extrudate physical properties and processing conditions.