Manure Removal Research Articles

Prevalence and risk factors for lameness in insulated free stall barns in Finland

Lameness is a painful condition that alters physiology and behavior of dairy cattle. The main objective of this study was to explore the prevalence of lameness in dairy cows, and its association with housing and herd management. Another aim was to identify poorly functioning structures and equipment that may contribute to increased lameness. Data on herd management, and barn design and functionality were collected in 87 herds, and the gait of 3459 cows was scored. Of the cows scored, 23% were lame (lameness scores 3–5; from slightly abnormal gait to severe lameness). The median within-herd lameness prevalence was 21%, ranging from 2 to 62%. The association between cow level lameness risk and cow specific risk factors was modeled with a logistic regression analysis. The odds ratio (OR) for lameness was for Holstein cows 1.6 (CI 1.3–1.9) times higher than for Ayrshire cows. Second and 3+parity cows were more likely to be lame than first lactation cows; OR 2.1 (CI 1.7–2.8) and 6.0 (CI 4.8–7.7), respectively. A herd level lameness prevalence estimate, accounting for the effects of cow’s breed and parity, was used as an outcome in modeling housing and management related risk factors. Lameness prevalence was lower in herds with a feed barrier divided to separate feeding places (0.17), compared to the ones with a post-and-rail (0.24). The lameness estimate was higher in herds with very slippery floors (0.31) than in herds with slightly slippery (0.16) or firm floors (0.16). The prevalence of lameness was associated with the width of a walking alley next to the feeding table, being 0.17 for herds that had alleys wider than 340cm, and 0.23 for herds with an alley narrower than 320cm. Lameness estimate (0.18) was lower if water was supplied from water cups only compared to water being supplied water from both cups and troughs (0.23). Most farmers had not adjusted neck and front rails properly in stalls, and had hard stall surfaces, compromising cow comfort. More than a half of the studied herds had problems with manure removal and urine drainage. Those findings suggest that there is a great need to educate dairy farmers and construction planners of the benefits and factors contributing to claw and leg health. Also, more emphasis should be placed to proper manure removal and urine drainage.

Effects of the cycle distribution on the performance of SBRs with aerobic granular biomass

The aerobic granular systems are mainly sequencing batch reactors where the biomass is submitted to feast–famine regimes to promote its aggregation in the form of granules. In these systems, different cycle distributions can be applied for the simultaneous removal of organic matter, nitrogen and phosphorus. In this work two strategies were followed in order to evaluate the effects of the cycle distribution. In the first experiment, the length of the operational cycle was decreased in order to maximize the treatment capacity and consequently the famine/feast ratio was also decreased. In the second experiment, an initial anoxic phase was implemented to improve nitrogen removal efficiency. The results obtained showed that to reduce the famine/feast ratio from 10 to 5 was possible by increasing the treated organic and nitrogen loading rates in the system to 33%, without affecting the removal efficiencies of organic matter (97%) and nitrogen (64%) and producing a slight detriment of the granules characteristics. On the other hand, the implementation of an anoxic phase of 30 min previous to the aerobic one with a pulse-fed mode increased the nitrogen removal of pig manure from 20 to 60%, while the cycle configuration comprising a continuous feeding simultaneous with an anoxic phase of 60 min did not enhance the nitrogen removal and even worsen the ammonia oxidation.

Agricultural zinc fluxes into soils and crops of central Iran at regional scale

Mass flux assessment can provide information that is essential for a sustainable management of elements in agricultural soils. In this article, we present an assessment of regional-scale averages of zinc (Zn) fluxes into agricultural soils and crops of central Iran for the period 1997–2011, using available databases such as regional agricultural statistics. The basic units of the balances were 15 townships of the provinces Qom, Isfahan and Fars. Averaged over the entire study region, the net Zn input into arable soil resulting from all fertilizer inputs – Zn removal with harvested crops was 1515 g ha−1 yr−1 across the entire region, with a range of 438–3009 g ha−1 yr−1 among townships. Estimated average Zn inputs with manure, mineral fertilizers, sewage sludge and compost were 1254, 531, 19 and 7 g ha−1 yr−1, respectively. The input-to-output ratio of these fluxes ranged from 1.8 to 12.9 among townships and averaged 6.1 for the entire study area. Considering that outputs other than with crop harvests are minor, Zn stocks are rapidly building up in the soils of the study region. Uncertainties in the manure and crop removal data were the main sources of estimation uncertainty in this study.

Seven years of repeated cattle manure addition to eroded Chinese Mollisols increase low-molecular-weight organic acids in soil solution

Organic amendments are an option in enhancing soil biological productivity. Limited research exists on the effects of long-term cattle manure addition on low-molecular-weight organic acids (LMWOAs) concentrations in corn (Zea mays L) and soybean (Glycine max L.) fields in the region of soil erosion. The purpose of this study was to investigate the potential influence of cattle manure on the LMWOAs concentration in erosion soil. A field experiment was established in Hailun city, Northeast China to determine the impact of long-term cattle manure addition on the total amounts of main LMWOAs in eroded Mollisol fields. There were three levels of simulated-erosion, which removed 0, 10 and 30 cm of topsoil. Two soil amendments were: (1) chemical fertilizer at the rate normally used by farmers in the region and (2) chemical fertilizer plus 15,000 kg ha−1 (dry weight basis) of cattle manure. Main LMWOAs in soil were assessed at the flowering stage of soybean and the jointing stage of corn. Compared to chemical fertilizer alone, 7-years of repeated cattle manure addition significantly increased total amounts of main LMWOAs in rhizosphere about 9–70 times and bulk soil about 6–62 times. The magnitude of increase by cattle manure was in the order of oxalate>malate>malonate>lactate>maleate in corn plots, and oxalate>malate>malonate>lactate in soybean plots. In comparison, cattle manure and topsoil removal had larger effect on LMWOAs concentrations in corn plot than soybean plot. The addition of cattle manure application and top soil removal had significant independent influence on main LMWOAs concentration in soil solution. This study suggested that addition of cattle manure would be an effective approach in modifying soil biological properties through the increases in low-molecular-weight organic acids to eroded Chinese Mollisols.

Brazilian beef cattle feedlot manure management: A country survey1

No information regarding the management of manure from beef cattle feedlots is available for Brazil. To fill this knowledge gap, a survey of 73 feedlots was conducted in 7 Brazilian states. In this survey, questions were asked regarding animal characteristics, their diets, and manure handling management from generation to disposal. These feedlots finished 831,450 animals in 2010. The predominant breed fed was Nellore, with average feeding periods of 60 to 135 d. Corn was the primary source of grain used in the feedlot diets (76% of surveyed animals) with concentrate inclusion levels ranging from 81 to 90% (38% of surveyed animals). The most representative manure management practice was the removal of manure from pens only at the end of the feeding period. Subsequently, the manure was stored in mounds before being applied to crop and pasture lands. Runoff, mainly from rainwater, was collected in retention ponds and used for agriculture. However, the quantity of runoff was not known. Manure was composted for only 20% of the animals in the survey and was treated in anaerobic digesters for only 1% of the animals. Manure from 59% of the cattle surveyed was used as fertilizer, providing a cost savings over the use of synthetic fertilizers. Overall, chemical analysis of the manure before application to fields was conducted for the manure of 56% of the surveyed animals, but the exact quantity applied (per hectare) was unknown for 48%. Feedlots representing 48% of the surveyed animals noted similar or greater crop and pasture yields when using manure, rather than synthetic fertilizers. In addition, 32% mentioned an increase in soil organic matter. Feedlots representing 88% of the surveyed cattle indicated that information concerning management practices that improve manure use efficiency is lacking. Feedlots representing 93% of the animals in the survey reported having basic information regarding the generation of energy and fertilizer with anaerobic digesters. However, only 1 feedlot implemented this technology. In conclusion, the manure management evaluated in this study represents an important indirect economic benefit that was represented by decreased use of synthetic fertilizers in crops. However, little attention was given to the specific treatments and environmental impacts of handling manure. This survey provides information that should assist in the development of better research practices and broader application of future models.

Skúmanie vplyvu frekvencie odstraňovania hnoja na množstvo vyprodukovaných škodlivín v ustajnení HD

The aim of the experiment was to determine the concentrations of harmful gases production in the dairy housing and to compare the difference of measured data in terms of frequency of manure removal. Measuring the concentration of ammonia, methane and carbon dioxide was carried out in summer in three-day cycles when produced excrements were removed every day at 19:00 o'clock, and in three-day cycles when removing of excreta was carried out twice a day, in the morning and evening at 5:00 and 19:00 o'clock. Microclimatic conditions during the experiment were at a comparable level, ambient temperature was maintained at about 29 °C and relative humidity was 64 %. By comparing the obtained values of production in terms of frequency of waste removal, it has been shown that for removing twice a day, the production of ammonia, carbon dioxide, methane was higher than under manure removal only once a day.

Effect of Pond Ash on Pen Surface Properties

<abstract><title><italic>Abstract.</italic></title> The maintenance of feedlot pen surfaces, which includes removal of manure and replacement of fill soil, is a time-consuming and expensive process. Pond ash (PA), a by-product of coal-fired electrical generation, has been proposed as a feedlot pen surface amendment because of its foundational support characteristics. A study was conducted to compare the performance of PA-surfaced pens to traditional soil-surfaced (SS) pens. Four of eight SS pens (7.3 m × 20.7 m) were excavated to a depth of 0.5 m and resurfaced with PA. The remaining four pens were kept as SS. Eight heifers were housed in each pen (19 m² head^-1) for four feeding cycles that ranged from 73 to 172 days. Following each feeding cycle, the animals were removed and the pens were cleaned. A subsample of the accumulated manure was removed from each pen for analysis of total mass (TM), total solids (TS), volatile solids (VS), percent volatile solids (VS%), moisture, and ash content. Higher heating value (HHV) was estimated using the VS% and moisture content. As compared to the SS pens, surfacing pens with PA reduced TM by 34%, TS by 34%, and ash content by 46%. PA increased VS% by 70% and HHV by 75%. Restoring the PA-surfaced pens to the original grade required only 25% of the amount of fill material required for the SS pens. However, there were no differences in the total amount of VS removed. Harvested feedlot surface material (FSM) from the PA pens was more nutrient and energy dense, based on the increased VS% of the collected material. The increased density improved the economics of transport and handling, and allowed for greater energy recovery. In addition, the PA pens were less erodible than the SS pens.

RELATIONSHIP BETWEEN THE METHOD OF MANURE REMOVAL AND SOME REPRODUCTIVE PROBLEMS IN HOLSTEIN COWS

RELATIONSHIP BETWEEN THE METHOD OF MANURE REMOVAL AND SOME REPRODUCTIVE PROBLEMS IN HOLSTEIN COWS

Herd-level risk factors for lameness in freestall farms in the northeastern United States and California

The objective was to investigate the association between herd-level management and facility design factors and the prevalence of lameness in high-producing dairy cows in freestall herds in the northeastern United States (NE; Vermont, New York, Pennsylvania) and California (CA). Housing and management measures such as pen space, stall design, bedding type, and milking routine were collected for the high-producing pen in 40 farms in NE and 39 farms in CA. All cows in the pen were gait scored using a 1-to-5 scale and classified as clinically lame (score ≥3) or severely lame (score ≥4). Measures associated with the (logit-transformed) proportion of clinically or severely lame cows at the univariable level were submitted to multivariable general linear models. In NE, lameness increased on farms that used sawdust bedding [odds ratio (OR)=1.71; 95% confidence interval (CI)=1.06–2.76] and decreased with herd size (OR=0.94; CI=0.90–0.97, for a 100-cow increase), use of deep bedding (OR=0.48; CI=0.29–0.79), and access to pasture (OR=0.52; CI=0.32–0.85). The multivariable model included herd size, access to pasture, and provision of deep bedding, and explained 50% of the variation in clinical lameness. Severe lameness increased with the percentage of stalls with fecal contamination (OR=1.15; CI=1.06–1.25, for a 10% increase) and with use of sawdust bedding (OR=2.13; CI=1.31–3.47), and decreased with use of deep bedding (OR=0.31; CI=0.19–0.50), sand bedding (OR=0.32; CI=0.19–0.53), herd size (OR=0.93; CI=−0.89–0.97, for a 100-cow increase), and rearing replacement heifers on site (OR=0.57; CI=0.32–0.99). The multivariable model included deep bedding and herd size, and explained 59% of the variation of severe lameness. In CA, clinical lameness increased with the percentage of stalls containing fecal contamination (OR=1.15; CI=1.05–1.26, for a 10% increase), and decreased with herd size (OR=0.96; CI=0.94–0.99, for a 100-cow increase), presence of rubber in the alley to the milking parlor (OR=0.46; CI=0.28–0.76), distance of the neck rail from the rear curb (OR=0.97; CI=0.95–0.99, for a 1-cm increase), water space per cow (OR=0.92; CI=0.85–0.99, for a 1-cm increase), and increased frequency of footbaths per week (OR=0.90; CI=081–0.99, for a 1-unit increase). The multivariable model included herd size, percentage of stalls containing fecal contamination, and presence of rubber in the alley to the milking parlor, and explained 44% of the variation of clinical lameness. Severe lameness increased with the percentage of stalls containing fecal contamination (OR=1.23; CI=1.06–1.42, for a 10% increase) and decreased with frequency of manure removal in the pen per day (OR=0.72; CI=0.53–0.97, for a 1-unit increase). The final model included both variables and explained 28% of the variation in severe lameness. In conclusion, changes in housing and management may help decrease the prevalence of lameness on dairy farms, but key risk factors vary across regions.

Increase of Soil pH in a Solar Greenhouse Vegetable Production System

Acidification of agricultural soil is attributed to excessive reduced nitrogen (N) fertilizer application and enhanced nitrate leaching. However, after an initial pH decrease, an increase in soil pH was observed in a solar greenhouse study. Within the vegetable planting areas in China, 3.3 million hectares of vegetables are planted in similar solar greenhouses. The objectives were to clarify the origin of this alkalinity. The results showed that, from February 2009 to January 2010, the total H+ production rate by base cation (BC) uptake of tomato plants and applied N fertilizer was 50.4 kmol ha−1 yr−1 for the control (CK), 68.3 kmol ha−1 yr−1 for recommended N treatment (RN), and 68.9 kmol ha−1 yr−1 for conventional N treatment (CN). However, the alkalinity inputs by irrigation were 96.1, 76.0, and 71.3 kmol ha−1 yr−1 for treatment CK, RN, and CN, respectively. Considering the alkalinity inputs generated by lime‐containing chicken manure (CM) and plant removal of phosphorus (P), the net residual alkalinity was 47.6 kmol ha−1 yr−1 for CK, 25.5 kmol ha−1 yr−1 for RN, and 20.4 kmol ha−1 yr−1 for CN and resulted in a rise in soil pH of 0.6, 0.5, and 0.2 units, respectively. In addition, net BC accumulation caused by irrigation, P and potassium (K) fertilizers, and chicken manure was 68.5 kmol ha−1 yr−1 for CK, 104.3 kmol ha−1 yr−1 for RN, and 103.5 kmol ha−1 yr−1 for CN. Results indicated alkaline factors from irrigation water (IW) alleviated the acidification of greenhouse soil but may eventually accelerate soil salinization. Groundwater table declines because of overwithdrawal in the region may be responsible for the increases in base cations brought to the greenhouse soil by irrigation. Therefore, a better water management has to be considered in the region.

Effects on Carbon and Nitrogen Emissions due to Swine Manure Removal for Biofuel Production

Methane (CH) and ammonia (NH) are emitted from swine-manure processing lagoons, contributing to global climate change and reducing air quality. Manure diverted to biofuel production is proposed as a means to reduce CH emissions. At a swine confined animal feeding operation in the U.S. Central Great Basin, animal manure was diverted from 12 farms to a biofuel facility and converted to methanol. Ammonia emissions were determined using the De Visscher Model from measured data of dissolved lagoon ammoniacal N concentrations, pH, temperature, and wind speed at the lagoon sites. Other lagoon gas emissions were measured with subsurface gas collection devices and gas chromatography analysis. During 2 yr of study, CO and CH emissions from the primary lagoons decreased 11 and 12%, respectfully, as a result of the biofuel process, compared with concurrently measured control lagoon emissions. Ammonia emissions increased 47% compared with control lagoons. The reduction of CH and increase in NH emissions agrees with a short-term study measured at this location by Lagrangian inverse dispersion analysis. The increase in NH emissions was primarily due to an increase in lagoon solution pH attributable to decreased methanogenesis. Also observed due to biofuel production was a 20% decrease in conversion of total ammoniacal N to N, a secondary process for the removal of N in anaerobic waste lagoons. The increase in NH emissions can be partially attributed to the decrease in N production by a proposed NH conversion to N mechanism. This mechanism predicts that a decrease in NH conversion to N increases ammoniacal N pH. Both effects increase NH emissions. It is unknown whether the decrease in NH conversion to N is a direct or physical result of the decrease in methanogenesis. Procedures and practices intended to reduce emissions of one pollutant can have an unintended consequence on the emissions of another pollutant.

The effect of cage and house design on egg production and egg weight of White Leghorn hens: An epidemiological study

Hen performance can be affected by many interacting variables related to cage design, such as floor area, height, tier arrangement, and feeder and drinker type and placement within the cage. Likewise, features of house design such as waste management and lighting can also affect hen productivity. The influence of these design aspects on hen performance has not been fully assessed. Determining the effects of numerous, interacting variables is impractical in a traditional experiment; therefore, an epidemiological approach, using variability in cage and house design among and within commercial producers, was employed to identify features that affect egg production and egg weight. A universal cage measurement system was created to calculate cage design variables. A database for recording information on cage design, resource location, waste management, environmental conditions, and hen productivity was developed. Production outcomes were assessed from placement to 60 wk of age in White Leghorns (n = 165-168 houses). Using GLM, a statistical model was identified that best described the variance in egg traits. Eggs/hen-housed increased with greater feeder space allocation (P = 0.031); taller cages (P = 0.029); rear (vs. front) drinker location in vertical cages (P = 0.026); and regular removal of manure from the house (P = 0.005). Case weight of eggs was greater in A-frame houses where manure was removed regularly instead of being left in the house (P < 0.001); with increasing cage floor slope (P = 0.001); in cages where drinkers were placed more toward the front or back of the cage as compared with the middle of the cage (P < 0.001); with more space/hen (P = 0.024); and with higher caloric intake (P < 0.001). Perhaps because of its negative correlation with egg production, case weight of eggs increased with less feeder space allocation (P = 0.004) and shorter cage heights (P < 0.001). These results reveal important effects of feeder space, floor space, cage height, drinker position, and waste management on hen productivity.

Effect of livestock manures on the fitness of house fly, Musca domestica L. (Diptera: Muscidae)

The house fly, Musca domestica L. (Diptera: Muscidae) is one of the major pests of confined and pastured livestock worldwide. Livestock manures play an important role in the development and spread of M. domestica. In the present study, we investigated the impact of different livestock manures on the fitness and relative growth rate of M. domestica and intrinsic rate of natural increase. We tested the hypotheses by studying life history parameters including developmental time from egg to adult's eclosion, fecundity, longevity, and survival on manures of buffalo, cow, nursing calf, dog, horse, poultry, sheep, and goat, which revealed significant differences that might be associated with fitness costs. The maggots reared on poultry manure developed faster compared to any other host manure. The total developmental time was the shortest on poultry manure and the longest on horse manure. The fecundity by females reared on poultry, nursing calf, and dog manures was greater than on any other host manures. Similarly, percent survival of immature stages, pupal weight, eggs viability, adults' eclosion, survival and longevity, intrinsic rate of natural increase, and biotic potential were significantly higher on poultry, nursing calf, and dog manures compared to any other livestock manures tested. However, the sex ratio of adult flies remained the same on all types of manures. The low survival on horse, buffalo, cow, sheep, and goat manures suggest unsuitability of these manures, while the higher pupal weight on poultry, nursing calf, and dog manures suggest that these may provide better food quality to M. domestica compared with any other host manures. Our results point to the role of livestock manures in increasing local M. domestica populations. Such results could help to design cultural management strategies which may include sanitation, moisture management, and manure removal.

Greenhouse Gas Emissions from Three Cage Layer Housing Systems.

Simple SummaryGreenhouse gas (GHG) emissions were measured from three different cage layer housing systems. A comparative study was conducted to identify the housing system with the least impact on the environment. The results showed that liquid manure from deep-pit housing systems produces greater emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) than natural and forced dried manure from belt housing systems. The influencing factors appeared to be the manure removal frequency and the dry matter content of the manure.Agriculture accounts for 10 to 12% of the World’s total greenhouse gas (GHG) emissions. Manure management alone is responsible for 13% of GHG emissions from the agricultural sector. During the last decade, Québec’s egg production systems have shifted from deep-pit housing systems to manure belt housing systems. The objective of this study was to measure and compare carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions from three different cage layer housing systems: a deep liquid manure pit and a manure belt with natural or forced air drying. Deep liquid manure pit housing systems consist of “A” frame layer cages located over a closed pit containing the hens’ droppings to which water is added to facilitate removal by pumping. Manure belt techniques imply that manure drops on a belt beneath each row of battery cages where it is either dried naturally or by forced air until it is removed. The experiment was replicated with 360 hens reared into twelve independent bench-scale rooms during eight weeks (19–27 weeks of age). The natural and forced air manure belt systems reduced CO2 (28.2 and 28.7 kg yr−1 hen−1, respectively), CH4 (25.3 and 27.7 g yr−1 hen−1, respectively) and N2O (2.60 and 2.48 g yr−1 hen−1, respectively) emissions by about 21, 16 and 9% in comparison with the deep-pit technique (36.0 kg CO2 yr−1 hen−1, 31.6 g CH4 yr−1 hen−1 and 2.78 g N2O yr−1 hen−1). The shift to manure belt systems needs to be encouraged since this housing system significantly decreases the production of GHG.

Influence of rearing conditions and manure management practices on ammonia and greenhouse gas emissions from poultry houses

Poultry production has been identified as a major producer of NH3 and, to a lesser extent, of greenhouse gases (GHGs) mainly by national emissions inventories. However, since most national inventories are based on average emission factors for each type of animal ('tier 1′ approach), the factors that influence these emissions (through breeding and manure-management practices) are not taken into account. The first step to improve inventories and propose mitigation options (e.g. best management practices, innovative systems) is a better understanding of the drivers of gaseous emissions and the identification of key factors for the mitigation of NH3 and GHG emissions. This paper presents a literature review of NH3 and GHG emissions from poultry housing, with a focus on the influence of practices and rearing conditions. It appears that flock-management practices (e.g. dietary practices, slaughtering age) and manure management (e.g. manure removal frequency, chemical treatment of litter) are presented as efficient ways to reduce emissions. Environmental conditions (e.g. ventilation rates, temperature) influence emissions; however, it was not possible to assess the effects of different combinations of these factors (compensatory or synergistic). Some factors, such as stocking density, which may play a significant role, were not studied. Modelling approaches that integrate these key factors with climate factors can be used to update emission factors in emissions inventories, consider national variability and uncertainties in mitigation scenarios, test synergistic and compensatory effects and avoid pollution swapping. Further research must be carried out to check the validity of emission factors and modelling parameters at a national scale.

Emissions of ammonia, nitrous oxide, and methane from aviaries with organic laying hen husbandry

The first objective of this study was to measure the year round emissions of ammonia (NH3), nitrous oxide (N2O), and methane (CH4) from three commercial aviary systems with organic laying hen husbandry. The second was to determine the effect on NH3, N2O and CH4 emissions of varying removal interval when using manure belts. Emissions were computed from the ventilation rate, calculated with the carbon dioxide (CO2) mass balance method, and gas concentrations of NH3, N2O, and CH4 inside and outside the hen house. Mean emission per hen for NH3 was 410 mg d−1, for N2O was 3.12 mg d−1, and for CH4 was 81.7 mg d−1. Mean predicted emission per hen for NH3 on the first day after manure removal was 298 mg d−1, and increased by 5.47% d−1. The presence of manure on the belt did not affect emissions of N2O and CH4. Emission of NH3 from aviary systems with organic laying hen husbandry was in the same range as emission of NH3 from aviary systems with non-organic laying hen husbandry. Using organic laying hen husbandry in aviary systems instead of single-tiered systems has the potential to reduce emissions of NH3, N2O, and CH4; further reductions might be realised by changes in litter management.

Comparison of shell bacteria from unwashed and washed table eggs harvested from caged laying hens and cage-free floor-housed laying hens

These studies evaluated the bacterial level of unwashed and washed shell eggs from caged and cage-free laying hens. Hy-Line W-36 White and Hy-Line Brown laying hens were housed on all wire slats or all shavings floor systems. On the sampling days for experiments 1, 2, and 3, 20 eggs were collected from each pen for bacterial analyses. Ten of the eggs collected from each pen were washed for 1 min with a commercial egg-washing solution, whereas the remaining 10 eggs were unwashed before sampling the eggshell and shell membranes for aerobic bacteria and coliforms (experiment 1 only). In experiment 1, the aerobic plate counts (APC) of unwashed eggs produced in the shavings, slats, and caged-housing systems were 4.0, 3.6, and 3.1 log(10) cfu/mL of rinsate, respectively. Washing eggs significantly (P < 0.05) reduced APC by 1.6 log(10) cfu/mL and reduced the prevalence of coliforms by 12%. In experiment 2, unwashed eggs produced by hens in triple-deck cages from 57 to 62 wk (previously housed on shavings, slats, and cages) did not differ, with APC ranging from 0.6 to 0.8 log(10) cfu/mL. Washing eggs continued to significantly reduce APC to below 0.2 log(10) cfu/mL. In experiment 3, the APC for unwashed eggs were within 0.4 log below the APC attained for unwashed eggs in experiment 1, although hen density was 28% of that used in experiment 1. Washing eggs further lowered the APC to 0.4 to 0.7 log(10) cfu/mL, a 2.7-log reduction. These results indicate that shell bacterial levels are similar after washing for eggs from hens housed in these caged and cage-free environments. However, housing hens in cages with manure removal belts resulted in lower APC for both unwashed and washed eggs (compared with eggs from hens housed in a room with shavings, slats, and cages).

Ammonia and Greenhouse Gases Concentrations and Emissions of a Naturally Ventilated Laying Hen House in Northeast China

This study quantifies concentrations and emission rates (ER) of ammonia (NH3) and greenhouse gases (GHG) including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from a naturally ventilated cage layer (Hy-Line brown strain) house with daily manure removal, located in northeast China during four seasons of one year, with each monitoring episode lasting five consecutive days. Gaseous concentrations of background and exhaust air were measured using an infrared photoacoustic multi-gas monitor with a multi-channel sampler. Building ventilation rate (VR) was determined by CO2 mass balance using literature metabolic rate data for modern laying hens. Both gas concentrations and ER showed considerable diurnal and seasonal variations. Annual mean (±SD) ER of NH3, CO2, CH4, and N2O for the monitored layer house were, in mg d-1 bird-1, 129 ±40.3, 78,250 ±15,384, 112 ±56.5, and 9.4 ±2.5, respectively, or in g d-1 AU-1 (AU = 500 kg live body weight), 33.4 ±11.4, 19,975 ±3,071, 29.2 ±15.2, and 2.5 ±0.7, respectively. Ammonia ER from the current study was within the ranges of values reported for high-rise houses with annual manure removal and manure-belt houses with daily manure removal. Results of the study contribute to improving ammonia and GHG emissions inventory for animal feeding operations in China and worldwide.

The Effects of Dietary Protein Content and Manure Handling Technique on Ammonia Emissions During Short-Term Storage of Dairy Cow Manure

An improved understanding of the potential for dietary protein manipulation to reduce ammonia emissions from dairy farms during various stages of manure handling is needed for both modeling and policy-making efforts. The objective of this study was to assess the effects of dietary protein manipulation on ammonia emissions from relatively freshly voided dairy cow manure in three types of removal systems: scraped manure removal systems, flushed manure removal systems, and flushed manure removal systems with a solids separator. Emissions were measured using a dynamic flux chamber for 12 h or more. Ammonia fluxes and emission factors per mass of manure were not affected by dietary protein content because fluxes depended mainly on total ammoniacal nitrogen (TAN) concentration, which did not vary with diet. However, emissions on a per-cow basis were 12% lower with the diet containing 15.0% crude protein as compared to the one with 17.8% (a change in crude protein of 16%) due to reduced urine output. The largest absolute impact of dietary protein manipulation would be with separated liquids because their emission factor was approximately four times higher than for the other types of manure. While dietary protein manipulation can reduce ammonia emissions from manure during long-term storage, its effectiveness in the hours immediately after manure is excreted is limited because emissions are more sensitive to other factors, including temperature and extent of mixing of the manure, that vary widely under real operating conditions on a farm.

Performance of geotextile-gravel bed all-weather surfaces for cattle

A cost-effective way of producing all-weather surfaces for cattle is to use a combined geotextile-gravel pad construction, which allows pavement depth to be reduced. This study sought to determine the pavement construction that would offer the least runoff, best drainage effect and highest quality runoff and drainage effluent after exposure to heavy precipitation under different manure loads in high animal density areas. The study also examined whether any pavement construction gave acceptable sealing to the underlying soil surface. Three different combinations of non-woven and woven geotextile together with two gravel fractions of 200 mm were exposed to 50 mm precipitation for 30 min and 15 kg of cattle manure under two manure regimes (manure removal and manure accumulation). Runoff, drainage effluent and leachate flow were measured and sampled in buckets as they exited their respective pipes for both regimes. The pad surface layer reduced runoff flow rate and stabilised drain flow throughout the experiments, confirming pad stability. Manure removal reduced total N, total P, chemical oxygen demand (COD) and total solid (TS) concentrations in drainage effluent. One pad construction proved better at oxidising NO 2 –N and another at trapping TS. One pad construction met the sealing liner norm to the underlying soil. The drainage effluent produced was acceptable for wetland treatment. The results show that geotextile and gravel pad constructions not only have a supporting and draining function, but also a filtering, aerating and sealing effect.