Search

Nutrients excreted from animals affect the nutritive value of manure as a soil amendment as well as the composition of gases emitted from manure storage facilities. There is a dearth of information, however, on how diet type in combination with dietary particle size affects nutrients deposited into manure storage facilities and how this affects manure composition and gas emissions. To fill this knowledge gap, an animal feeding trial was performed to evaluate potential interactive effects between feed particle size and diet composition on manure characteristics and manure-derived gaseous emissions. Forty-eight finishing pigs housed in individual metabolism crates that allowed for daily collection of urine and feces were fed diets differing in fiber content and particle size. Urine and feces were collected and stored in 446-L stainless steel containers for 49 d. There were no interactive effects between diet composition and feed particle size on any manure or gas emission parameter measured. In general, diets higher in fiber content increased manure nitrogen (N), carbon (C), and total volatile fatty acid (VFA) concentrations and increased manure VFA emissions but decreased manure ammonia emissions. Decreasing the particle size of the diet lowered manure N, C, VFAs, phenolics, and indole concentrations and decreased manure emissions of total VFAs. Neither diet composition nor particle size affected manure greenhouse gas emissions.

An experiment was conducted to determine the effect of feeding finishing pigs a corn-soybean (CSBM) diet or a CSBM diet supplemented with 30% dried distillers grains with solubles (DDGS), in combination with or without a growth-promoting ionophore (0 or 30 mg narasin/kg of diet), has on manure composition, microbial ecology, and gas emissions. Two separate groups of 24 gilts (initial BW = 145.1 kg, SD = 7.8 kg) were allotted to individual metabolism crates that allowed for total but separate collection of feces and urine during the 48-d collection period. After each of the twice-daily feedings, feces and urine from each crate was collected and added to its assigned enclosed manure storage tank. Each tank contained an individual fan system that pulled a constant stream of air over the manure surface for 2 wk prior to air (day 52) and manure sampling (day 53). After manure sampling, the manure in the tanks was dumped and the tanks cleaned for the second group of pigs. Except for total manure Ca and P output as a percent of intake and for manure methane product rate and biochemical methane potential (P ≤ 0.08), there were no interactions between diet composition and narasin supplementation. Narasin supplementation resulted in increased manure C (P = 0.05), increased manure DM, C, S, Ca, and phosphorus as a percent of animal intake (P ≤ 0.07), and increased manure volatile solids and foaming capacity (P ≤ 0.09). No effect of narasin supplementation was noted on manure VFA concentrations or any of the gas emission parameters measured (P ≥ 0.29). In contrast, feeding finishing pigs a diet containing DDGS dramatically affected manure composition as indicated by increased concentration of DM, C, ammonia, N, and total and volatile solids (P = 0.01), increased manure DM, N, and C as a percent of animal intake (P = 0.01), increased manure total VFA and phenols (P ≤ 0.05), decreased gas emissions of ammonia and volatile sulfur compounds (VSC; P = 0.01), increased emissions of phenols and indoles (P ≤ 0.06), decreased methane production rate (P = 0.01), and slight differences in microbial ecology (R ≤ 0.47). In conclusion, feeding a diet which contains an elevated level of indigestible fiber (i.e., DDGS) resulted in more fiber in the manure which therefore dramatically affected manure composition, gas emissions, and microbial ecology, while narasin supplementation to the diet did not exhibit a significant effect on any of these parameters in the resultant swine manure.

During the twentieth century, U.S. agriculture strived to achieve increased food production in order to satisfy both local and export demands. In many cases, this led to increased farm sizes and an operational separation of crop and livestock production. The trend of increasing centralization and industrialization of agriculture, specifically animal agriculture, has resulted in the concentration of waste products associated with animal production (manures and wash-down water) over relatively small geographic areas that are spatially segregated from crop production areas. Because the distance that manure can be economically hauled for land application has practical limits, the public is concerned that this spatial separation of crop and animal production areas could lead to over-application of manures near animal feeding facilities, and thus potentially increase the transport of nutrients to ground and surface waters. An aggregated analysis (statewide) of crop and animal production in Iowa suggests that about 30% to 40% of current nitrogen and phosphorus requirements for crop production could be supplied from manures and litters generated from livestock production, while about 50% of potassium requirements could be supplied. However, neither livestock nor crop production in Iowa is uniformly distributed across all counties. This unequal distribution suggests that a more disaggregated analysis of crop nutrient requirements and manure nutrient supply is necessary to estimate the risks of excess nutrient loss to the environment. Thus, we evaluated crop nutrient demand and manure and litter production at the county level to determine if excess manure generation is of concern and to locate areas where additional manures could be used. Results showed that several counties are becoming manure rich, but most locations maintain sufficient capacity to use manure nutrients effectively. Keywords: Crop nutrient capacity, Manure management, Manure production, Nutrient balance, Nutrient management.

In recent years the corn grain ethanol industry has expanded and led to increased availability of dried distillers grains with solubles (DDGS), and feeding DDGS to swine is becoming more common in pork production. With feed being the primary cost in pork production and increasing interest in air emissions from animal feeding operations, it is important to understand the impacts of non-traditional dietary formulations on aerial emissions. The purpose of this study was to evaluate the impacts of feeding DDGS on ammonia (NH3), hydrogen sulfide (H2S) and greenhouse gas (GHG) emissions from deep-pit swine wean-to-finish (5.5 – 118 kg) facilities in Iowa, the leading swine producing state in the USA. To attain the study objectives, two commercial, co-located wean-to-finish barns were monitored: one barn received a traditional corn-soybean meal diet (designated as Non-DDGS regimen), while the other received a diet that included 22% DDGS (designated as DDGS regimen). Gaseous concentrations and barn ventilation rate (VR) were monitored or determined semi-continuously, and the corresponding emission rates 28 (ER) were derived from the concentration and VR data. Two turns of production were monitored for this study, covering the period of December 2009 to January 2011. The daily and cumulative emissions are expressed on the basis of per barn, per pig, and per animal unit (AU, 500 kg live body weight). Results from this project indicate that feeding 22% DDGS does not significantly affect aerial emissions of NH3, H2S, CO2, N2O or CH4 when compared to the Non-DDGS regimen in a deep-pit wean-to-finish swine facility (p-value = 0.10 for NH3, 0.13 for H2S, 0.55 for CO2, 0.58 for N2O, and 0.18 for CH4). ER for the Non-DDGS regimen, in g/d-pig, averaged 7.5 NH3, 0.37 H2S, 2127 CO2 and 72 CH4. In comparison, ER for the DDGS regimen, in g/d-pig, averaged 8.1 NH3, 0.4 H2S, 1849 CO2, and 48 CH4. On the basis of kg gas emission per AU marketed, the values were 8.7 NH3, 0.724 H2S, 2350 CO2 and 84 CH4 for the Non-DDGS regimen; and 12 NH3, 0.777 H2S, 2095 CO2, and 60 CH4 for the DDGS regimen. Results of this extended field-scale study help filling the knowledge gap of GHG emissions from modern swine production systems.

Methane emission is an important tool in the evaluation of manure management systems due to the potential impact it has on global climate change. Field procedures used for estimating methane emission rates require expensive equipment, are time consuming, and highly variable between farms. The purpose of this paper is to report a simple laboratory procedure for estimating methane emission from stored manure. The test developed was termed a methane production rate (MPR) assay as it provides a short-term biogas production measurement. The MPR assay incubation time is short (3d), requires no sample preparation in terms of inoculation or dilution of manure, is incubated at room temperature, and the manure is kept stationary. These conditions allow for high throughput of samples and were chosen to replicate the conditions within deep-pit manure storages. In brief, an unaltered aliquot of manure was incubated at room temperature for a three-days to assay the current rate of methane being generated by the manure. The results from this assay predict an average methane emission factor of 12.2 ± 8.1 kg CH4 head(-1) yr(-1) per year, or about 5.5 ± 3.7 kg CH4 per finished animal, both of which compare well to literature values of 5.5 ± 1.1 kg CH4 per finished pig for deep-pit systems (Liu et al., 2013). The average methane flux across all sites and months was estimated to be 22 ± 17 mg CH4 m(-2)-min(-1), which is within literature values for deep-pit systems ranging from 0.24 to 63 mg CH4 m(-2)-min(-1) (Park et al., 2006) and similar to the 15 mg CH4 m(-2)-min(-1) estimated by (Zahn et al., 2001).